SARS

A changed world – scientific advances to combat covid-19

COVID‐19 is an emerging infectious disease caused by SARS‐ CoV‐2 virus. Since the first 4 cases reported in Wuhan on Dec 29, 2019, the COVID‐19 pandemic has spread to 191 countries, infecting over 18 million people, and causing over 690,000 deaths. The new virus spreads rapidly from person to person and causes serious illness in some patients. Since the virus and the disease it causes are still relatively unknown, the risks can only be assessed with great uncertainty.

This coronavirus is unprecedented in the combination of its easy transmissibility, a range of symptoms going from none at all to deadly, while targeting the weakness of the immune system. It survives on non‐living surfaces (remained active after 17 days on surface of Diamond Princess cruise ship). It can spread during incubation, without symptoms, post‐recovery, and through fecal matter. The virus has already mutated and is highly adaptable. Currently there is no definitive treatment and no vaccine against COVID‐19. It challenges care and treatment paradigms, and many healthcare workers are infected and traumatized.

The devastating global impact of SARS-CoV-2 has fueled extraordinary scientific discovery. This website highlights recent scientific and mathematical modeling advances that are driven by on-the-ground evidence and clinical findings. It includes timelines on policy recommendations along the disease journey since late December 2019.

January 2020

Recommending Community Testing in United States (Starting Jan 24)

Jan 24-Feb 7

• Global: Airlines reach out to cover all international travelers where their flight of origin is China and Europe, not just Wuhan. Individuals who are willing to provide nasal swab and sputum samples can report to the nearest health department. We can also give them a little form to do contact tracing themselves.

• Regional-based approach: Reach out to schools, religious organizations, private businesses, etc, to promote testing among those who have recently traveled out of the country to China or Europe. Workforce travel is common in this connected world.

Jan 17-Jan 24 cohort and so forth (reverse tracing, Jan 10-Jan 16, Jan 1-Jan 10 etc).

• Cascading effect: Clearly they may not have any viral activities if they have already shed and passed it onto someone else. But the contact tracing form will be useful.

2019-nCoV

SARS, MERS-like pneumonia, but distinct from SARS, MERS

• More infectious, suspected to be infections during last stage of incubation

• Confirmed asymptomatic cases and successful transmission (some debate)

  • e.g. Germany 1^st case, exposed on Jan 21/22, developed symptom on Jan 24, and recovered by Jan 27

  • Have few confirmed infected case of children under 15

  • Asymptomatic transmission or transmission before onset was rare in the SARS outbreak.

Confirmation

• In China: Ct-value< 37 positive at both local lab and national China CDC lab using real-time RT-PCR with 2019-nCoV–specific primers and probes. 37 < Ct-value <40, retesting via full genome sequencing

• Outside China: 3 confirmed positive tests

Human to Human Transmission

• Our early model predicted that 80-88% cases are human-to-human transmission. [[No data fitting, just model based on environment, human, viral behavior and disease patterns.]]

• Fits very well with data presented by a study on 425 cases (published in JAMA on Jan 29)

Graph is from JAMA article https://www.nejm.org/doi/10.1056/NEJMoa2001316

Quarantine, Protection, and Hospitalization

• Quarantine (strict isolation): Models show that individual isolated quarantine is critical within the military base to avoid cross-infection due to asymptomatic cases.

• Protection: All workers must be well-protected. (Note: PPE supply-chain disruption)

• Special Care: Models also suggest treating 2019-nCoV patients separately in a temp. wing/appendix outside hospitals. Most death reported have coexisting health conditions. Thus 2019-nCoV patients should stay far from hospital ED/ICU for obvious reason of cross infection (or absolute isolation must be ensured). Dedicated sites also facilitate rapid learning and sharing of treatment knowledge and symptoms among workers.

• Fact: Confirmed by a study with 133 patients, 41% of hospital patients and healthcare workers were infected in the clinic early on (before they realized it's a novel coronavirus). China set up mass temp. hospital tents and use of military medical personnel.

German cases

• Narrative: A Chinese subject with no apparent symptoms traveled to Germany for a conference. Upon return to China, the Chinese subject was tested positive on Jan 26 of 2019-nCoV.

• Index case: 33 year-old healthy German met the Chinese subject on Jan 21/22, began exhibited symptoms on Jan 24, recovered and resumed work by Jan 27, shedding of 2019-nCoV after recovery, tested positive on Jan 30

• One infected directly from the Chinese subject, two indirect from the 2 German.

• Fact: Rapid disease life-cycle among healthy individuals; evidence of potential post recovery infection.

2019-nCoV Disease Parameters

• Incubation: mean 5.2 days, 95^th percentile 12.5 days (10 confirmed cases), infectious later stage

• Infectious: Symptomatic and asymptomatic

• The serial interval: 7.5 days, defined as the delay between illness onset dates in successive cases in chains of transmission. (based on 6 pairs of cases)

• Testing sample: nasal swab and sputum work well (based on lab leaders on the ground)

• Within 2 days upon symptomatic, 27% seeks medical help, mean 4.5 days

• Take 8-9 days from showing symptoms to being hospitalized

• Average recovery rate of hospitalized individuals, is about 9 days.

• Asymptomatic patients may never be tested nor treated. Highly likely they will recover and may become immune. Potential post-recovery shedding. They are exporting diseases effectively across different regions

• Healthcare workers are at high-risk of contracting the disease

• Must prevent contact with healthy people: Infectivity and fatality rate will reduce

• Constrain by number of available beds: if there are no available beds, patients can only be treated at home.

Our Stochastic Compartmental Model for 2019-nCoV

Develop a novel computational framework that combines

• A stochastic 8-stage complex disease model: Susceptible, Expose, (P) Infectious, Asymptomatic, (I) symptomatic, (Q) Recovered still infectious, Recovered not infectious, Deceased

• An agent-based human-behavior and social environmental descriptor module

• A logistic resource (hospital + personnel) surge and operations module

• An optimizer to determine the best timing of action and resource allocation

Parameters: Wuhan China

• Intervention begins on January 23, 2020 (today), report results for 90 days and 180 days out

Effect of Extra Bed/Hospital Resources

• 20% of symptomatic patients are hospitalized

• Increase beds and medical personnel to take care of needed patients

• Number of available beds (from news) increases:

  • Day 0 to day 45: 100 beds

  • Dec 30, 2019: Day 45 to Day 68: 900 beds

  • Jan 23: Day 68 to Day 75: 3000 beds

  • Jan 30: Day 75 onward: 5000 beds (not completed yet)

Comments

• Model

  • • Account for asymptomatic cases (not tested and not reported)

    • Shift disease start date to Nov 15 2019 to account for reporting and testing delay

      • • I suspect this is the timeline for patient 0 – Nov 15 2019

    • Align reported cases to symptomatic cases

    • CFR used is 2.0%, should be lower to account for asymptomatic and unreported cases

    • Many more computational tests are still in the running, plus optimizing hospital resources for rapid containment

    • Incorporate human and social behavior and situation awareness

• Exportation of pre-symptomatic cases are unavoidable

• Global experience may be that of self-sustained outbreak,

• Infection closer to flu than SARS (much is still unknown)

• May not be as deadly as reported estimate, but definitely very infectious

Strategic Disease Containment

How to stop the disease spread?

Disease Containment:

1. Case Isolation: Prune the disease nodes (those red ones) so they cannot continue to spread.

2. Divide and Conquer: Separate the nodes as much as possible so there is no means to contact and thus cannot spread.

Aggressive Disease Containment

• Must test strategically

• Must perform case isolation

• Must perform contact tracing

• Must perform at the ports of entry – to prevent reaching to communities

• Timing is CRITICAL!

February 2020

Seasonal Influenza vs 2019-nCoV (Feb 7)

Seasonal Influenza in United States:

• Estimate to affect ~26 millions Americans (~8.1%)

• Resulted in ~200,000 hospitalizations (~0.7%)

• ~34,000 deaths (0.13%)

2019-nCoV in Wuhan (2018: 11 millions, a mixed of residents & workers, 2019: ~14 million)

• 16,902 Confirmed cases (0.18%, with total shutdown within a month)

  • Accounting for those asymptomatic cases: total estimate ~26,000 cases

  • Untested cases (very mild / short disease duration): ~40,000 cases [~0.18% - 0.44%]

• 3,340 (20%) severe/critical conditions, 1,017 cured and discharged

• 681 deaths (4%) [[~1.7% - 4%]]

• Public health Risk: Over 10 – 30 times more deadly than flu! More infectious than SARS! And we know very little about it!

• Rapid export: according to local news, by the time the city was lock down on Jan 23, 5 million have already left the city for holidays!

Diamond Princess Analysis (Feb 6-9 2020)

News and Opportunities

• Reported: Feb 10 2020, confirmed 174 cases among 389 selected/tested individuals

• Narrative: Index case - an 80-year old flew from China to board at Yokohama on Jan. 20 before disembarking back home on Jan. 25. No symptoms on board. Tested positive 6 days (Jan 31)

• Model findings: Use most aggressive virus spread parameters – infectious upon exposure, asymptomatic. or symptomatic infectious for 5 days, shedding upon recovery (remains infectious), R0=3, contact rate > 3.4. At most can generate 25 infections over a 10-day period; 140 over 21-day period.

• What happens? Super-spreader? This man was not the index case, multiple (unknown, asymptomatic) infected cases to begin with? airborne? Or just standard cruise environment?

• Opportunity: Largest outside China. A unique environment to screen (all or at least a good sample or mixed and no-symptoms ones) beyond the 336 identified individuals to study infectivity, symptoms, disease progression patterns, hospitalization needs, etc. Strategic testing is a MUST.

Comparing 3 diagnostic testing strategies

• Current action (select those with symptoms and elderly): Estimate R0 for current status, start day Jan 20, gradually select individuals for testing run it to 35 days

• Rapid mass testing on all individuals: Use the uncovered R0, start on Feb 4, perform tests on all individuals in 24 hours, obtain results by Feb 8 and disembark all to appropriate settings based on test results.

• Regulated quarantine with strategic testing: Use the uncovered R0, install proper isolated quarantine on Feb 6, perform strategic testing, and continue until all are tested

Must have: Proper Quarantine/Isolation, and Rapid Testing

• Regulated proper quarantine – strict isolation – can compensate for lack of rapid testing

• Must enforce high compliance in individual isolation

• Allow for strategic testing where mass testing is still currently lacking

  • Achieve 4-fold infection and mortality reduction (when compared to the non-sampling approach that Japan is currently doing)

• Mixed implementation across regions: some rapid mass testing, and some proper strict quarantine with strategic testing. Allow us to optimize limited testing capacities across different regions

Cruise situation reinforces the importance of strategic testing and timing for NPI

• Worry about schools, malls, workplaces, need implementation of NPI now!!

Timing and Effect of Non-Pharmaceutical Intervention

Distributed to King County, California, Maryland, New York, CDC

So Little is Known

• 2019-nCov is unprecedented in the combination of its easy transmissibility

• A range of symptoms going from none at all to deadly, while targeting the weakness of the immune system.

• Survives on non-living surfaces (remained active after 17 days on surface of Diamond Princess cruise).

• Can spread during incubation, without symptoms, after post-recovery, and through fecal matter (airborne? from Diamond Princess).

• The virus has already mutated and is highly adaptable.

• Currently there is no definitive treatment and no vaccine against COVID-19.

Challenges in US

• Insufficient diagnostic testing capabilities and capacities

• Vaccines do not exist and no definitive treatment

• Even with 1% population infected, the healthcare system will be overwhelmed. Doctors must treat patients via trial-and-error and provide supportive care

• Must implement community mitigation measure Non-pharmaceutical intervention (NPI): closing schools, wearing face-masks, social distancing, case isolation and quarantine, contact tracing, and avoiding large public gatherings

• Strategic is key: not one-size-fit-all

Objectives: Evaluate Intervention Effectiveness

• Analyze the disease spread of COVID-19 while incorporating human and social behavior and hospital resource and operations logistics

• Estimate the effect of NPI of school closure and business tele-work practice on disease spread and containment

• Evaluate hospital surge for effective containment

• Evaluate (community) testing effectiveness

Combination strategies is key

Decisions: When to do it, what to do, and how to do

Timing and Overall Effect

• Establish predictive models on NPI for various cities in January and February

• Analyze the overall effect of NPI

• Highlight difference across different sites and optimal timing for implementation

Saving Lives, Lessen Health Systems Burden

• Strategic testing: Aggressive case isolation, quarantine and contact tracing

• School closure

• 50% government telework

• Face masks in public (transit > 99% compliance)

• Social distancing at work

• No sports events

• Private business follows suit

  • • 50% telework

    • The rest staggering shifts

    • Separate workspace

    • Labor work poultry /meat farm workers wear PPE

    • Labor work garment factories (face-mask, farther distance)

    • Face-mask if distance is < 7 feet

• Environment (disinfect and personal hygiene)

Expected improvement: Timing and Scope of NPI

• Uniformly across the U.S., timely school closure can potentially reduce 32%-77% the total infection within 4 weeks, and 98% within 12 weeks. A delay of two weeks would render only 1-27% reduction in the initial month, and 94% by 14 weeks.

• Adding 50% tele-work workforce can reduce infection over 77% within 4 weeks and 97% within 8 weeks.

• Without NPI, and with 400 bed availability, about 48% -85% of population will be infected by the end of 150 days.

• Specifically, if NPI is put in place in United States by January 31, it will result in 4,199 – 6,796 infections and 106 - 125 deaths. A delay of one month (February 29) will increase the infection to 194,453 – 248,474, with deaths ranges from 4,668 - 6,005. Highly like we won't put NPI until mid or late March, by then the overall infection will increase to 2,406,043 – 4,349,246, with mortality ranges from 76,227 - 204,789.

Timing: Note the exponential growth in infectivity and mortality, as NPI implementation is delayed.

Decision makers: It seems difficult for them to act early. But acting early offers a better outcome with shorter shutdown period and economic downtime. Containment is always desirable in pandemic, since community spread is difficult to control.

Tradeoffs on Decision – Public Health and Emergency Response (February 14)

Virus adaptability: It seems that the virus is really rather adaptable to the human body, capable of exploiting the health conditions to assert different types of symptoms, thus making it hard to treat and to diagnose. In that case, it can come back with more power.

Public health strategy (and public perception): I understand there continues to be debates on if/when we should put in full throttle of effort. My feeling is -- Public health always faces such a dilemma.

a. Nothing bad will happen and we put too much resources and effort

b. Something bad really happens and that we mitigate and make it go away -- this is a good effort and result, but understandably it will be underappreciated because no one would know how it would play out without intervention and how bad it is. So successful mitigation is often under-valued. [[people will think it is just (a).]]

c. Something bad happens and we did not do enough -- that is a big fall out everyone knows.

I think it is very important we take path (b) and treat (a) as a real test of how good we can mount a full fight. The lab tests are the first bottleneck (besides all the biological and clinical understanding of the virus). We should lay it all out all sequences of effort and develop a full plan. It is not going to be like a flu plan-- because we don't know much about this virus. But we certainly can adapt it.

I incorporate the disease models within the network of critical infrastructures. This virus could disrupt many layers of the supply-chain networks, truly affecting the whole world. Consider it a real ugly test that we can blanket it and win it, it is a must.

Clinical cases: Please safeguard clinical data and treatment response. That will be invaluable. That will be invaluable and I would like to perform machine learning to uncover patterns and correlations.

Evidence of NPI from Hong Kong and Singapore (Feb 29)

• Validate if the model works for other countries’ on-the-ground situations.

• Input: 5 imported COVID-19 confirmed on Jan 25 2020. The city declared a state of emergency and decided to close schools and began home-office for government. This triggers private sectors to begin home-office practice also. Run our model with population in Hong Kong, school population and workforce statistics.

• Output: The predicted infectivity and mortality

• Validation: Plot the reported cases onto the predicted graph

The analysis shows remarkable positive impact of disease control via NPI! Timing is critical.

Trigger (to act)

• Hong Kong declared a state of emergency on Jan 25 when it has 5 confirmed cases, all from Wuhan travelers. No community spread yet.

This graph is as of February 29, a clear evidence of NPI working. The city did not close up, rather, only school closure, and encouragement of tele-work. Government engaged in tele-work as an example. Church service goes online. All other services remain open with no restrictions. Everyone is using face mask, but it is not a mandate.

• Washington and California - within the specific pockets -- should start closing schools and special facilities, apply NPI and all necessary actions to halt this initial stage of disease spread. We need to put a brake to buy us time and we need rapid screening.

• Singapore - not clear what triggers were used, but population is used to obey healthcare orders because they have regular orders and they execute immediately with everyone follows orders or else faces severe punishment. The difference between Singapore and Hong Kong is that Hong Kong does not have penalties like Singapore. Hong Kong relies on situation awareness and citizens take NPI guidelines seriously.

Hand Hygiene - Washing with Water vs Sanitizers

We have passionately debated hand washing with water or sanitizers and what's better and what's needed.

I urge grocery stores provide hand sanitizers and position them conveniently everywhere. This is extremely critical for both the workers and the customers. Also it is absolutely not feasible to use self-checkout unless such hygiene is being put in place. I was at Kroger, there're 6 self-checkout in one lane. Everyone touches everything and there's not a single thing to wipe or clean before each customer. You don't need a model, nonetheless, I did some time-motion study and then built a model to characterize the contact, unbelievable, the contact is over 90%!!

Please, sanitizers everywhere and self-checkout must be safeguard with all necessary cleaning. If there're hand sanitizers there, they can do magic. It is easy and a must-have.

March 2020

Even 1% is too much to bear (March 5)

1. The sustained and multiple level of demand: Yes, the whole idea of a sustained increase demand of ICU, ED, and outpatient access is what troubles me the most. Yes, I truly believe in timely intervention because the downstream effect will be magnified with every delay. And yes, I am fixated with 1%. [[and I will explain more why that is a critical % to me below]] Moreover, we have problem with outpatient access. This has been a huge problem for VA, but really it is a problem with other outpatient sites also. Have you ever called for an appointment? The earliest they can see you could be like 3 weeks from your call. We will be so overwhelmed in no time.

2. Systems-view: Ever since the "requirement" of last mile effort of dispensing antibiotics for an anthrax attack within 48 hours, some public health officials (and citizens alike) criticized the (Bush and Obama) administration's obsession with anthrax and think that this whole idea of 48 hours is absurd. In 2013-2015, I did a vaccine prioritization analysis to determine the percentage of high-risk groups we should vaccinate first before opening the dispensing to the general population. The objectives are to minimize the total infection and mortality. Not surprisingly, you don't always give the vaccines to all the high-risk groups first due to herd immunity effect. There is an optimal percentage that could be determined depending on inventory level and how they're shipped. I call that point the "prioritization trigger".

In this same study, I also analyzed the delay in vaccination and how it will affect the outcome. It shows even with a delay of 1 week, the total infection would increase by 0.5%. So 0.5% for the State of Georgia is about 50,000 people. Even if only 10% of them need medical care, it is still a lot of extra people. This underscores the importance of rapid dispensing -- regardless if it is for anthrax, or for any infectious diseases. We can't handle a huge bunch of sick people because we won't be able to figure out all the unknown that could happen simultaneously. Hence time is critical. When to act is critical, not just how to act. The key is that it is the whole system that is inter-connected. Hence, we need to see that not only one component gets disrupted, it is everything that gets disrupted. We are not being tested like this. Hence I also view this (now) as a perfect time to test our planning capability and to see how well the federal agencies and states/local are collaborating and communicating.

Perhaps our decision makers are better dealing with catastrophic events than this lingering disease breakout. But I challenge that notion that we can only act when it goes to the worst possible extreme. I think we must act in a timely manner because we're not the first country to get infected. We have seen enough around now (2 months). We have criticized enough. Now we have quite many pockets of fire, and perhaps we can't be too shy in making the decisions.

3. Contingency plan: The finance sectors in UK have asked me to help them design a contingency plan in the event of a pandemic or terrorist attack a few years ago. And they really follow it, not just in UK, but in other branches all over the world. This is true for some of the private sectors here in the US where they have to make decisions about big meetings and events. Perhaps companies have to act because there is financial and client interests that they must take into account.

4. The young population: Today a medical colleague called me. She wants me to do some predictive analysis on cardiovascular diseases. Then she started complaining about GT. So here's our little fire related to COVID-19: Lorraine campus in France has quarantine 1/3 of the students. Due to Spring break, they went to Italy and then they're all being exposed / contact-traced to some of the Italy's covid-19 patients. My colleague told me -- her son has asthma, not all that healthy. She said the university refuses to close campus. Instead, they quarantine everyone in the dormitory and feed them food. She just wants him to come home safe and sound. Yes, he should come home indeed. So I wrote to the Dean and complained about the Lorraine campus situation. I know nothing will be done because they will wait for local officials to tell them what to do. I am not sure local officials here will even know /think about the Lorraine campus. That is a mini-fire. But what about the young population who have chronic diseases? Are they safe from this covid-19? Do we know?

5. The covid-19 dog: Tracey asked about it. Here, finally some results

Officials first tested the dog on Feb. 26 and found low levels of coronavirus from its nasal and oral samples a day later. Two repeat tests earlier this week resulted in a “weak positive” for the virus, the department said.

How did they enter the US? (March 6)

I want to use our work on "Assessing Cybersecurity Threats on Critical Infrastructure: Uncover Hidden Vulnerabilities for Maximum Protection", a DHS-sponsored project that involves interdependencies and cascading effects of disasters on critical infrastructure to analyze COVID-19. It goes beyond pandemic since it involves analysis of multi-layer of critical infrastructure risk networks and influence analysis. One scenario I have completed involves the aviation network and maximum influence. Each node (think about airport, but it can be anything) carries different risks depending on many factors: e.g., physical, passengers, security, resource, and economics. You can also put different weights on the factors to guide the analysis. Below is one result from Feb 15 2019 when we did some runs based on various objectives. These are the airports that assert the maximum system impacts and hence most vulnerable.

- *LAS (Las Vegas), *PHX (Phoenix). *DEN (Denver), *ATL (Atlanta), *MCO (Orlando)

- *LAX (Los Angeles), *ORD (Chicago), *FLL (Fort Lauderdale, near Miami), DFW (Dallas), Kahului (Hawaii)

- *MSP (Minneapolis), DTW (Detroit), *SEA (Seattle), *BWI (Baltimore-Washington), SFO (San Francisco), *JFK (New York),

I am curious and wanted to see how many of these airports have travel-related COVID-19 cases. The pink stars are confirmed cases. The blue (just MSP) are travelers with direct contact to a confirmed covid-19 not allowed to board the plane back to US, self-quarantine, not tested. San Francisco does have covid-19 but not related to travel. Dallas, Hawaii don’t have any covid-19.

This illustrates interdependencies and connectivity provide a good system-risk framework for a broad spectrum of scenario predictions.

NPI, test kits, supply-chain for protective gears, hospital surge, the difference and time, and economy (March 7)

1. NPI accelerates and sustains containment: It looks like we can predict really well how NPI and other pre-emptive measures can truly slow down and help contain the spread. When I ran the intervention model for Hong Kong, as seen, the results match to perfection the on-the-ground situation, same for Singapore. You can also see very well how delay will affect the containment, as I showed the 1 week, 2 weeks delay etc. You can imagine that already on your head, just keep in mind disease spread without intervention is not linear, hence all the worries. California needs to act. They have too many fires and I don't really know what it takes (for them to act) [[See item 5 on multiple fires and attacks]]

2. Test kits: Back in January, we worry about not having enough testing kits. This is still unknown. The best scenario for us is to have sufficient test kits so that we can do community testing in an intelligent and strategic manner. E.g., we can't just test 100 people on Princess. That is unacceptable. I will write more as I am running some analysis and I want to show you the graphs.

3. Supply-chain disruption for protective equipment: Perhaps the president has solved this problem, I don't know, but this is true and it will get very bad when we have many patients who need hospitalization.

We are not counting supply-chain of daily necessary things for citizens. It will become more urgent as time goes.

4. Hospital surge and tele-health service: Remember the 1%. That is truly a test for us, and we must equip ourselves. I know Grady told me they could put out 100+ or even 200+ beds when needed, but these would be for what patients? If all the covid-19 patients need to be in isolation units, we really need make-shift medical tents. James and others are experts there. I think we need to think ahead. I can help with optimizing the logistics, but recall, 15,000 beds and 4000+ healthcare providers, that's how many China added, on top of their existing ones.

5. The difference and time to act Wuhan is one city. They acted slower than they should have. So a huge slam on the brake to slow everything. We are no longer contained in one city. We have multiple fires. Recall when I first learnt of CBRN from all of the experts here back in 2006, we talked about multiple sources of attacks. We are exactly in this situation now. It is the system and the inter-dependencies and cascading effects that are truly challenging and demand TIMELY action. By that, if we need 100 beds now and we don't have it, then next week, to get the same outcome, we will need 251 bed, etc. You can see those intervention curves. They are not just for NPI, they can be for any intervention. Putting out NPI immediately we can stop 59% infection, a week later, only 42%, and another week later 22%. You see it is totally NOT linear. So slow reaction means we have to pour even more resources and still may never achieve the same outcome. This is absolutely true about testing. So there is testing, there're NPI measures to put in place. And then hospitals, every level from top to bottom requires timely action.

6. Economy The longer this is dragged on, the harder it is for the economy. Everything is inter-connected and hence rippling effects.

Community Screening and Diagnostic Testing for COVID-19 Biosurveillance (March 10)

Distributed to CDC and local emergency responders

Rapid Screening and Testing: After Spread

Screening and testing are essentials for disease contentment and mitigation

• Screening: Rapid screening helps to identify at-risk individual, surveil community, and determine disease prevalence.

• Testing individuals for covid-19: are critical to confirm and determine the scope of spread of covid-19 within the community.

• Tracking and contact-tracing should be performed simultaneously during these procedures.

• Local should develop guidelines pertinent to their needs and current disease status.

• CDC guidelines

  • • “Screening” refers to “epidemiologic risk assessment” described here and informed by “documented COVID-19 infections in a jurisdiction and known community transmission”.

    • “Testing” refers to “initial diagnostic testing” defined here.

COVID-19 Testing Tents (initial diagnostic testing)

• Locations

  • • Next to hospitals: more manageable for PPE usage

    • Pharmacies: Ubiquitous

• Key Steps

  • • Workers doing the test: must wear PPE for full protection

    • Administrative/paperwork: register, paperwork

    • Tests: collect nasal swab and sputum samples

    • Discharge:

      • • Educational document

        • Contact information

• Please ensure proper PPE are used for all workers

Steps for Testing COVID-19

1. Registration (in a booth separating cars from staff)

• 1. PUI will be contacted, so all information is already in place. Registration time is minimal.

  2. Open POD drive-through. Register online, use QR information for smartphone to click, or paper form at site

• Explain the process: There is only one task-testing

• Give out information about testing: positive, negative, implications

2. COVID-19 testing (in PPE interacting with subject directly)

• Collected by a PPE-protected healthcare professional

• Caution: should go all the way through the nostril deep into the pharynx slowly and carefully trying to touch the mucus membranes that are being swabbed.

Screening Tents (“epidemiologic risk assessment”)

• Locations

  • • Ubiquitous so citizens can go easily: Grocery store parking lots, Walmart, Target, Walgreens, etc ?

    • Near COVID-19 test sites: pharmacies, hospitals, more manageable when PPE is used, and if sending high-risk cases directly to testing sites.

• Key Steps

  • • Administrative/paperwork: register, paperwork

    • Screening: based on age, symptoms, health conditions (co-existing conditions) and other criteria

    • Discharge:

      • • provide appropriate risk level and guidance on action

        • If needed, send for covid-19 test

• Please exercise appropriate social distancing

Medical and Personnel Surge (March 12)

Treating the Sick

• As we prune the disease nodes and breaking down the network connectivity, we must also treat covid-19 patients properly to minimize the mortality

• Need space/beds, personnel, equipment for these extra patients

3. Medical Surge: Personnel Procurement

• Include medical students in regular patient care.

• Engage private-practice physicians for regular hospital service. (Many private practice physicians cancel their clinical service and have minimal work engagement.)

• Enlist retired nurses and physicians

• Hire out-of-town private practice providers who have cancel their private practice (Licensing issue perhaps can be handled by EUA). Every State has to prepare.

• Enlist providers (those reside in US already) who have physician practice license outside US (e.g., UK and European providers).

• Utilize VA doctors (see below on tele-health)

These individuals can be used for regular patient care. Depending on their background, e.g. pulmonary physicians can be good for assistance in covid-19 patients, medical chief can decide on their assignment and training.

Medical Surge: Design of Care

• Regular patient zone: Separate regular hospital patients from covid-19 patients. This is to minimize cross-infection and for ease of transition of care by new/extra surge as above and also to minimize use of PPE.

• COVID-19 zone: Serve them in a manufacturing-type streamline-type design. Divide them by zone – by severity, by type, etc so that it’s easy for nurses/providers to come in to provide medication, take vitals, perform rounds, and take X-rays etc, Use notepad and stick them to wall next to patient indicating days since arrival. Big enough so you can see them from a distance. These numbers are important as these patients will be tested at strategic interval. Someone comes in and can walk through rapidly take a nasal swab or sputum. By zoning, you can also minimize the number of providers who will be there simultaneously. If you do it by zone, you can make the team lean at each shift.

• Lean approach: Understand that at each shift the providers will tend to a lot more patients than normal (by design), then you can make the shift to be 6 hours instead of 8. In doing so, you have fever personnel using PPE simultaneously, yet you see more patients, hence you are reducing the PPE usage. Stretching it to 4 shifts per day – 6 hours per shifts, the number of PPE can be reduced significantly. I did a few models and in all cases, we can save between 10%-20% of personnel.

• Utilize tele-health and video-health to manage patients who need routine medical care. We cannot overlook regular patients who need medical care. VA has good telehealth facilities and they can provide surge across states.

Care Operations

• Open floor ICU design / field hospitals

• Maximize care team coordination

• Minimize traffic

• Allow rapid knowledge sharing and collaboration

• Zone patients according to different symptoms/disease types to streamline clinical care, maximize throughput of clinical team.

• Think economies of scale

Surge Clinical Care

• Identify all personnel, resources you currently have

• Identify current utilization

• Identify layout and sites

• Surge will escalate from 15% increase to 50% increase rapidly (within a day or two), then go beyond (2-7 folds) depending on the epi curves of your region

• Make-shift beds in a large ICU can help with throughput and also for mass treatment.

• Set aside a dedicated staff for disinfection, use the ultraviolet system for disinfection if you have it

Bed Surge for New York City (March 15)

• Timeline

  • Day 1: Feb 20 2020

  • Week 4: Complete implementation of school closure and at least 50% business tele-work

• Medical Surge Analysis

  • How bed surge can help drastically reduce overall infection and mortality

  • Add surge on April 1: 10,000 beds (open-floor ICU) and 5,000 low-acuity beds (hotel/dorm)

  • Add daily covid-19 testing: Test at least 5000 suspected cases (NYC has many symptomatic cases that are turned away because of lack of testing kits and hospital beds).

• ICU: Reminder: must separate regular and covid-19 patients.

• Telehealth: Use it in regular and covid-19 ICU to help with the on-the-ground surge

Findings and Actions

• Bed surge is EXTREMELY important and essential in saving lives

  • • Reduce overall mortality by 89% - 95%!

    • Reduce overall infection by 87% - 94%!

• Contrasting Week 3 *(blue), Week 4 (green) and Week 5 (purple) NPI implementation shows significant difference in overall infection and mortality.

• Week 4/Week 5 results are what we will expect regarding NYC covid-19 situation with bed surge.

• Surge provided on April 1 is a MUST to blunt the rapid spread within NYC. Delay implementation will decrease the benefits and many more people will die.

Face Masks - Effectiveness in reducing infection (March 15)

Analyze face-mask usage in a macro level in terms of minimizing infection (just as the HAI that I have done for multiple hospitals that have reduced HAI successful by over 25%-78%). The analysis includes scenario of no masks, sparingly used, 50%, 70%, and 100%. It also optimizes the best coverage.

When community spread is minimal, If we can get 50% to 70% people to wear face-mask, we can potentially reduce the spread by about 15%. At 100% we can obtain a reduction of 20%. There is herd immunity -- once the asymptomatic ones covers their face, and a big group of healthy ones cover too, it provides a safer environment. It is true to say that those who don't wear one will put themselves and others at a greater risk.

The optimal compliance is 90%. At this rate, a 20% infection reduction will be achieved.

Requirement? I don't know how we can require citizens to wear N95, but at the minimum, some sort of face cover for protection should be good. I think face mask in grocery stores and service business is a must. I need that and I want that to happen -- because this is the first order of defense against the asymptomatic individuals. Washing hands frequently is good. Sanitizers are good to have in the stores and in business. There is secondary order of defense regarding cleaning clothes frequently after wearing them outside. I know I threw away all the clothes after my work in the Fukushima site. But if I had a washer, I would have washed them. This is personal hygiene. Basically remove everything sheds onto our body off by showering and washing.

When I analyze this in the model, face-mask does protect us against asymptomatic patients (recall 15-20% reduction in infection). Now, if there is no asymptomatic, then fine, we can go out without any physical barrier. But these individuals, even if they just talk to you, you know that saliva does fly quite far away. So absolutely as long as asymptomatic is around, you have to protect yourself. And they have to protect themselves from infecting others. So make it a two-way protection, not one way. I know there're advocates who think we can punish people if they infect others. Really what good does it do to punish them, our goal is to reduce infection, getting some penalties/monetary return don't really help us. Those fines can barely cover the healthcare expenses. And they clearly cannot buy-back the lives we lost.

I think proper usage of face mask and face covering is good and should be enforced. Let's not make it an option. Make it a requirement and see how well citizens can comply.

How do our models reflect the current on-the-ground situation? (March 24)

Plot the current infections and deaths onto the model graphs designed in February. We do this every month (a prospective analysis) to see how our prediction fares.

Observations: Uniformly for every city that we have analyzed, by the time the first positive case was confirmed, it is already 2-4 weeks behind. The challenges are multiple folds:

• Not enough testing kits

• Non-strategic testing: Only symptomatic individuals are tested, asymptomatic cases are entirely missing.

• Delay in results reporting

• High false negative rate

One case is one too many. One death means there are hundreds of positive cases in the community.

Warnings

On the ground: Malls are closed, so no one is in the mall. We will see pockets of outbreaks in apartment complexes. Lots of people gather as a group and they are 1 foot from each other with over 20 or so people, practicing "social distancing together". And they are drinking. So perhaps this will spark some local apartment-type outbreaks. Can be very serious.

New source of infection -- Please all the doctors here must take note and spread to everyone to ensure protection. Labor and postpartum patients who showed no symptoms of covid-19 at all developed symptoms during delivery or post delivery and were subsequently tested with covid-19. The entire provider team have to be placed on quarantine.

New guidelines immediately put in place:

• all labor patients will be tested before admission.

• all labor patients will be given and required to wear a facemask

• extra protection is given to the delivery team

• no partner/spouse is allowed to be in the delivery room.

• extra FTE will be used to care for all the babies.

Many covid-19 patients exhibit different symptoms than CDC guidelines and hence they were "discovered" too late and thus infected/exposed healthcare workers

Our staff is shrinking because of the continuous head-on infection. Please protect them.

The economics of scale care concept must be applied. Must re-arrange the care units for optimal access. And organize covid-19 patients so that it is easy to do rounds, provide medication, lab tests etc. This allows providers to keep the care team lean and thus reduce PPE usage and foot traffic. This also allows for rapid knowledge sharing and dissemination, since care team is going to be rather heterogeneous over time.

The epi curves: The curves for Italy, Spain, France, Germany, etc, all look rather similar though some are steeper than others. The US one looks a bit weird as it looks like an abrupt sharp increase with so little at the beginning. This is due to lack of testing at the beginning. Currently since we are still testing very limited number, we are seeing the delay effect. These patients are already in the hospitals when they are being tested, whereas on average, it takes 5 days before a patient with on-set convid-9 symptoms to be hospitalized.

Mild-Symptom Patients

There is debate as to where to put those patients with mild but obvious symptoms that need clinical care. It seems better to put them in isolation in either hospital or hotel for treatment, than to keep then at home. They will infect the entire household unless they can isolate. Putting them in a single zone along with similar type patients (in hotel or medical tents) allow for easy round of examination and advice to maintain their good health upon recovery.

Evidence has been shown regarding post recovery RNA shedding (German patient zero Jan 31 test). So these patients remain infections. So ideally recovered patients should be tested to confirm negative results and no shedding.

This little virus is too smart -- it infects rapidly and it is not letting go of the hosts even after they recover. Very very tricky. It is testing our ability (every one of us) to be patient and to isolate. We need lots of space, lots of medical equipment and personnel.

Next wave of worries is that people (the worry-well) will be depressed as they are staying at home.

What we can learn from the unknown

What we see in Wuhan is only a partial picture -- we truly have no idea what's happening there. However, the way the disease spread, we can immediately deduce that it rapidly becomes human-to-human, how else would it spread so fast. Further, even with such constraints, the spread was wide. Look closer to Wuhan's population -- it's 11 million then. One percentage of it is 110,000. And now they reported over 81,000 cases With so little that is known, this is the partial information we have. Here's an infection of "<1%" which demands +27000 beds and +42,330 extra medical doctors from all over the country, I think that explains a lot -- the severity of the patients, the unknown medical conditions and how they are presented in a diverse manner, the long duration of hospitalization, and everything else that you can imagine.

If I plug that 1% into Georgia, with over 140 hospitals -- and I have all the data on isolation units, medical personnel etc, it is frightening.

Italy is the first country where we can see the disease spread and the data is a bit better. The healthcare system is strained since they don't have as much support as in Germany, France, or UK, and perhaps they couldn't follow the social distancing as required.

Disease Gravity

I think models should not be data fitting. It should give us insight on what can be done / learnt from. Wuhan is a perfect example of how much we don't know. So I don't care about anything we don't know. I care about what implications these unknown provide us. Thus, I abandon the data points right at the beginning and just think about the environment of spread, their actions, and their inaccurate data reporting, plus everything we cannot tell from a distance. The graphs are supposed to tell us, beyond everything we don't know and what they didn't want us to know, this is what they are going to show us. Not bad as an estimate, because it shows the gravity on what we must do.

I do not believe anything coming out from China, but I take their shutdown seriously. They would do so when they have absolutely no choice. Hence, that should be our trigger of imminent danger.

Decision makers here cannot decide because they have a hard time making decisions that are so drastic with so much unknown. They will wait until they have absolutely no choice.

We do need a lot of space/beds and people in New York City

Here's what Wuhan used: 27,000 hospital beds, 13,348 new beds for mild symptom, ~70,000 quarantine beds

• The 27,000 beds included newly built ones for covid-19 and also re-organizing existing hospitals to setup covid-19 wings. [[include the 2 new medical buildings]]

• The 13,338 new beds for mild symptoms were established by using convention centers, or small stadiums of some type and setup for treating mild symptoms.

• The 70,000 quarantine beds - were setup using dormitories and hotels, these were contact-tracing at risk groups.

Recall in Hong Kong [[We know this already.]]

They utilized new public estates that were just recently completed but not yet occupied. The government took the step on Jan 25 to allow usage of these new buildings to quarantine all travelers from high-risk countries. Because it has all in-house facilities and brand-new, it worked very well.

Now, they are running out of space, and they have many more travelers to quarantine, hence they are using digital devices, wrist-bands and smartphone app. etc to help trace travelers, if they are not self-quarantining themselves properly.

These are not too invasive for us since we have apps in US already where people can sign on when they arrive at a certain city to find out whose around in the neighborhood that you can hang out with. It should work for us for contact tracing.

Grave Situations in New York City

I understand the extraordinary challenge that is faced by clinicians as they have to deal with such diverse disease symptoms.

• Many people came into the hospital with covid-19 symptoms. Too many are turned away because hospitals do not have enough testing kits and bed space. Doctors admit they realize these patients are probably covid-19, but simply no test-kits nor hospital beds. So all are turn away.

• They go home to do self-quarantine. But their home is in an apartment. This is their social distance and cluster. Recall all these apartments are going to be extremely critical.

• There is no way an infected individual would encounter noone in the apartment -- in the elevator when they go out to get food. You know how small those elevators are. You would be lucky to be 2 foot apart and you absolutely will be touching everything.

• NYC is spreading like fire. Please they MUST have many many testing kits and tons of beds!!!

Everyone here, your community -- you will see clusters of apartment-type outbreak because of gatherings of these people, they may not be intentionally (as seen in NYC because of tight living quarters), or perhaps some simply are not thinking about gathering. Your testing must cover A BIG circle to cover all the networks. You must do so to choke the disease node (a whole branch now) off to stop it from continue to spread. This is a must for every single place, because it is exponential. Remember, exponential in absolute no time.

• Lots of very sick patients with lots of different symptoms -- e.g., diarrhea, smell problem, pain somewhere, just all sort of symptoms outside CDC guidelines,

• Pregnant women who came in perfectly healthy looking but then developed all sort of symptoms during labor or post-partum. As it turns out, they are covid-19 too.

• Please it is extremely extremely important to separate covid-19 patients vs in-patient of non-covid-19 type inside the hospital care. That is a must to ensure no cross-infection, It is also important for healthcare workers to dedicate to one type, so we can ensure economies of scale and conserving PPE.

• Of all places, early closing schools and telework would mean so so much and so crazily important for NYC. I understand people are worrying about economy. There's no economy if the fire continues to rage on.

New York City needs:

• Test kits: everyone who goes to the hospitals for test MUST be tested, because they are all sick (as the doctors admitted that) and they need beds. Please make sure -- 10,000 -- if they can set up now They need all of them. And they will need more. Pull out all these individuals from the community.

• Ventilators: they need lots of ventilators. NYC is the heartbeat of US -- a symbol as in 911. So we must save them.

• Healthcare workers: these individuals cannot be tested (no kits) and they are extremely vulnerable. In some hospitals, providers go in to treat regular patients and then go back to treat covid-19 patients. No change in face mask and all. They CANNOT do that.

• Triage at ED: It is important to separate the patients right from the start. Since test is not real time, it means everyone comes in will be so uncertain. A temporary holding place with regular disinfection is a must.

We must fight for them. NYC has 1/2 of the covid-19 infection among the US statistics, at the very least, they should better get enough of what's in Stockpile.

Some very important observations:

• Separate the deaths : mortality in nursing home offers different aspect. The chance of those individuals spreading (to outside) like fire is low. Yes they do infect their family members. But since unfortunately they are weak and perish fast, it kills off the spread. Family members may not be as fast in spreading.

• Death among outside nursing home takes more note -- because they indicate a wider spread in the circle of that individual. A bigger branch needs to be pruned and harder to prune.

• The Spring break in Florida and the Mardi Gras in Louisiana help fueled the spread. Check out New Orleans to ensure it doesn't explode.

• San Diego (not at risk, I am just discussing the pattern), which I have looked at for Eric, has interesting pattern. The initial spread is totally non-linear and much faster than it should have been. The source looks more like 20 cases to start with. So lots of hidden cases not seen yet.

• And many healthcare workers will die, they are not being tested, they are sick, and they are overworked.

• And I want to know what happens to the 5 million test kits (according to the WH briefing). How come noone has enough and NYC has only 5% of what they need.

Case Discovery and Our Model Prediction

Look at this graph, the little death rate (real one) follows precisely what was predicted and it seems to start to follow the school closure curve.

Moreover, just as we all suspected, we discovered the first case too too too late. The first appearance means we are 2-3 weeks behind, Maybe even more, because some of these sites have traveler cases, and we assume they're all caught. But they're not. This one has 5 infected cases to begin with.

NYC is more like Lombardy and Wuhan because of the heavy foot traffic and dense population. But unfortunately NYC is more -- because the buildings are taller and hence denser number of people. Hence, please pour as much resources as possible. They are running on pretty empty tank. We must step on the brake really hard (test kits, beds, medical personnel, low-acuity-care). People die -- regardless of the age -- if they don't have sufficient supporting medical care.

New York City real data against the predicted ones. It shows delay in awareness and also in testing and confirming. Too late. School closure just happens last week, so there's no effect there yet. They are still in the discovery mode as the infected ones are everywhere. And it seems that they do see many symptomatic cases (even those being turned away have strong symptoms). So many more if we count the asymptomatic cases. But clinical prognosis seem more severe for some patients. I do not know how they can capture such diverse symptoms in a systematic way. But the data would be invaluable.

As I mention, the mathematical equations are established from one time point to another, moving along with the disease progression. Hence there is not a single set of equations to describe the entire horizon, rather, it is a set of equations through a time interval, and then it changes again in the next. It allows accurate robust prediction, but it is not a closed form (to write out in a pretty manner). I am going to estimate that function, so we can write it out easier to read and use.

A bit sadness from the CEO as he sees darkness, but he is hoping they will see sunshine soon. They remain very short on testing kits and do not have enough beds. They continue to reject lots of patients who need tests and who need hospitalization.

Yes, very sad. they are already depressed... and this is only the beginning. They are not peaking yet. I just want them to get appreciated. It's very hard since I can only optimize and I cannot do anything.

This is not looking good, not looking good at all. It is spreading and with much more fuel. In a sense, I expect the 2nd level of risk cities/states, they just come up faster and stronger. We must procure all local available personnel and truly getting the convention center, hotels, and drive-through in place. Truly if there's any extra, people will move themselves.

So, for school closure, immediately it means February 20. 1 week is Feb 27, and 2 weeks is March 5. That is also why I was so vocal that week making everyone closed schools and do tele-work. NYC was way ahead from others, and their local transmission was slow to pick up (tested and confirmed), even now. Now their infection rate is below because they don't have test kits. And the doctors on the ground acknowledge that they see many sick covid-19 patients being turned way. All the infection we are seeing now are many olds+new. The infection is much higher than reported now -- we are not testing fast enough to be able to record all these covid-19 cases. At this point, they still lack many many testing kits. And the doctors are getting depressed seeing so many patients being turned away.

The line for closing schools and telework was not on the graph since it happens just last week. I will add it back on.

Here's how it looks for New Orleans, exactly the same pattern as NYC. Let's hope buildings are shorter and community spread and clusters are smaller. Truly New Orleans and Louisiana MUST be very prepared! It started with 10 infected cases. You can see the delay awareness, and the escalated death, the same pattern as we have seen.

April 2020

1. ILI trend; NYP has stopped all respiratory tests for two weeks already. They have no resources to continue. They are testing only covid-19 on all admitted patients. So the ILI is going to be skewed and missing many. I suspect the spike would be very significant if you have all the tests.

2. Face masks: Some of you asked me about how I got the 15-20% reduction in infection with face-mask usage. It is a conservative estimate as I model the activities and risk factors of various groups of people. Since we can't see the asymptomatic patients, hence they will continue to infect. With face masks, we reduce their infectivity. So this is one source, may be a very significant source given that we still have no strategic testing in place and I don't know how the contacting tracing is working either. So anyone without symptoms won't be tested. So we are probably missing a lot of them.

3. Taiwan: Taiwan is not as busy a travel hub as Hong Kong or Singapore. Travel between Taiwan and mainland has always been strained. So they have very few imported case from China. Second, Taiwan people use face-masks all the time. Basically everyone is masked now. But even long before covid-19, people use face-masks if they are not feeling well or in congested areas where people wear it for precaution.

4.. Hong Kong: I learnt something new today. Recall in all models, I assume only 50% business do tele-work. That is reasonable to account for compliance, and since some business remains open and some are small and they can afford to be sparse. So today I learnt -- in Hong Kong they also interlace the working days. So for a business who cannot work at home due to the nature of work, they split working into MWF and TThu shifts and they interlace their hours also. So complicated. But it works beautifully. Everyone is safe and healthy. And business leaders have custodian disinfect properly after shifts.

Second, I also learnt about gatherings. Their gatherings now -- as they emerge a little bit from the peak in China -- is loosening a bit and is allowing 4 people in a gathering. E.g., For restaurant, every table is triangulated with maximum distance (8 feet). The further away the better. Also because of shedding of RNA, even those surface becomes a source of infection. Hence, it simply doesn't worth to be so close to each other. The servers always wear gloves.

For my own math interpretation, note the number 4 -- is not about if people get infected. Of course, if there's one infected person, those other 3 can also be infected. It is that the cluster is small enough and hence we can contact trace faster and thus can control faster. Again, all these math is about case isolation and divide and conquer.

Hong Kong has the ability to rapid test and do contact tracing. We must have this. We absolutely need these.

5. Singapore: Singapore does not enforce face mask usage in public. I think it works well for a while because the disease was still very much confined to Asia. But once it gets international, sources coming in through travel spikes so high and so rapidly. With asymptomatic lurking around, you have no choice but needs to put in certain public guidelines. I really don't know how penalties work.

6. Deaths in US: This is heartbreaking. We aren't the first country to have covid-19, we aren't even second country. This is just so tragic.

https://www.cnbc.com/2020/04/06/new-york-city-weighs-temporary-burials-as-coronavirus-deaths-overwhelm-mortuary-system.html

Diagnostic Testing

CVS is offering drive-through covid-19 testing and can test about 1000 per day (it said at max). They are using Georgia Tech campus.

Recall, dormitories are empty so you can use as low-acuity-bed sites. Campus is also empty too so it can be a very good drive-through sites.

The CVS uses the Abbott kits. Now it's testing about 190 pre-screened PUI people.

Recall this is our drive-through / walk-in "PODs" that we have been talking /exercising for the last 10-12 years. I have them all listed on RealOpt. If we can get many of these sites operational, that will take off the burden of the healthcare systems. Pharma can do a good job since they have proper medical training. PPE remains critical.

Registration becomes easier since Pharma has patient registering system links to various hospitals.

Strategies for Re-Opening: Optimal Testing Sample Size and Resource Requirement (April 7)

Some Critical Issues Regarding Re-opening

• Prevent SARS-CoV-2 virus from spreading again

  • • Measured business rollout and reopening

    • Advised personal and social behavior adaptation

    • Compliance

    • Strategic sample testing, Type I and Type II errors

• Strengthen health care system to sustain service for regular and covid-19 patients

• Address mental resilience of population (at all levels)

• Risk adaptive approach

Measured Business Roll-out

• Personal hygiene and behavior: face-mask, frequent handwash, more frequent laundry

• Business environment: Disinfect frequently and procure hand sanitizers

• Groceries: 6-feet markers at queues, hand sanitizers at each cashier stand, protective shield between customers and cashiers, frequent disinfect

• Restaurants: potential if we can reduce size to be 4 with table distance of 8 feet (people may enjoy such privacy in dining)

• Business: space out by staggering work hours (MWF, TTh) and work shift.

• Religion service: smaller size

• Large events: depends on location and risk posture (see results)

• School: remain close for summer. When open in Fall, can be smaller size

Strategic sample testing

• Sample across different sectors – groceries, service industries, prisons, nursing homes, hospitals, apartment complex, homeless, … [Universities and schools will be included once open.]

• Rapid daily drive-through covid-19 testing via pharma or setup by public health emergency responders. Will optimize throughput and locations of testing sites using RealOpt©.

• Determine who’s responsible to pay for testing kits and processing of lab results

• Systematic data collection and analysis. RealOpt© can collect all these as POD manager can login and transmit all files. It can become so easy to track and analyze everything.

Re-opening strategies

• Determine when to re-open

  • • At which risk posture should a city/jurisdiction reopen

    • How to re-open (business, daily services, religion groups, schools)

• Determine optimal testing sampling size for disease containment

  • • 1% to 3%

    • Testing accuracy

• Case isolation requirement

  • • Use dorm/hotel rooms

• COVID-19 Hospital bed capacity

Risk-based Adaptive Approach

Assess current scope of infection (infection per capita, mortality per capita) to determine its risk posture

• High risk: Sustained and widespread infection, 4 weeks within infection peak

• Medium risk: Reasonable community infection control, ability to test, at least 4 weeks outside the peak, decrease in daily infection counts

• Low risk: Community spread is minimum, good infection control throughout, sufficient testing capacity

We can start ranking different states/jurisdictions into different categories to allow for priority re-opening

Interpretation of graphs

• The analysis is for a city of one million

• Look ahead for 8 months, 5 months, 3 months to understand potential disease spread with re-opening and ability to contain

  • • Timeline is critical to match availability of vaccine or potential good treatment

• Each color corresponds to risk level + opening strategies

• Line type denotes amount of strategic sample testing and accuracy

  • • 1-3%, 100% accuracy, 80%, 50%

    • 20% of those infected sampled and with severe symptoms will be hospitalized

    • 50% of those infected sampled will be pulled into low acuity units

    • Account for potential Type II errors of false negatives

    • Account for sampling uncertainties (how many positives come in for tests)

• Assume 100 covid19 beds are available

The 7 lines for each of the color represents respectively:

No testing, test at 1% per day with accuracy 50%, 80%, 100%, test at 3% per day with accuracy 50%, 80% and 100%. These graphs show the new infection calculated from the day of re-opening.

Testing capacity: For high-risk re-opening, we can see a difference of 100,000 to 200,000 infections between 1% test versus 3% test within 4 months (10-20% of the population!). This underscores the importance of sufficient testing.

Timeline to re-open: Medium-risk re-opening (dark red) can reduce over 75 - 99% of infection within 150 days (when compared to high-risks). This showcases the danger of premature re-opening while the sites are still at high-risks. Cities must be vigilant in determining their re-opening schedule.

It is very important we DO NOT re-open while sites are still at high-risk. It will result many fire. The public and the citizens must be patient.

Medium-risk reopening while maintaining school closure offers a very viable and safe strategy to re-open, with schools gradually and strategically re-open in the Fall (September). To achieve medium risk, sites must have good testing capacity, good control of community spread, and can sustain local infection with decrease in number of daily infection, and 4 weeks outside the peak. Re-opening at such level can happen in July, but not earlier.

Medium-risk with school closure and some telework can offer a robust and safe re-opening environment. It is important policy makers are patient and do not re-open prematurely.

Comments

• Optimal diagnostic sampling size: 3%. Sampling 1-3% can make a huge difference in total number of infection.

• Reopen at "medium risk with school closure and 25% tele-work" (for those natural IT-type jobs) offers a cost-effective and safe disease-controlled environment.

• County/city-based approach: We should rank cities/states into each category and start roll-out for re-opening.

• Big cities with most vibrant service business will take a bit longer to re-open.

• Pre-mature reopening of major cities that are still on fire will lead to severe disease spread, potential second wave as in Spanish flu due to mutation. Must proceed with caution in those hard-hit cities. Too many infected individuals still. Cannot re-open, not in 4 weeks.

Important Info Everyone Must Know

On April 8, NYP has more discharged than admitted. Bad news is that number of patients require ventilators are on the rise.

Within 3 weeks, hospital beds surged to over 6-folds!

Personnel: The NYC hospitals are overwhelmed, and beds are pretty packed, and they are running short of staff also. They will have clinical teams from UCSF and Cleveland Clinic to add to their personnel.

N95 masks: Besides covid-19 providers, they’re now providing to ED and inpatients, since many may be covid-19 also. Still shortage and still are looking at ways to re-sterilize and re-process. They are also trying to re-sterilize the ventilator hoses.

Tests: start testing sick healthcare workers with symptoms. Please see attached. Worth reading and to be on alert for providers.

Treatment There continues to have no proven therapy for covid-19. Disease is in 3 stages:

• Viral infection

• inflammatory response where the immune system is essentially on overdrive

• if that continues that could lead to complications and tissue injury (recall I mentioned about the deep lung tissue scars)

Investigation al approaches

• Antiviral Remdesivir – interfere with virus, given to many patients – don’t know if it works yet.

• Immunomodulators – that change the way the immune response works

• hydroxychloroquine – for Malaria and some autoimmune diseases e.g., lupus and rheumatoid arthritis. In the test tube, it does have activities against the virus that causes covid-19. Available in the market. Without convincing data, doctors have been offered to patients on a case by case basis.

Testing Testing remains extremely important. Again what you are seeing in NYC in terms of infection is not because R0 is 6. R0 is not 6. On the ground, we are seeing many *sick* patients who are being turned away from testing because the hospitals run out of testing kits. So yes, you will see infection continue to rise (see below why) and you must test and take them out.

You must test, test and test more, isolate them and stop them from spreading into the community. Also, you must do strategic sampling testing, you cannot just test the ones who are sick/symptoms. Ok I know your hands are tied with limited resources. Find the testing kits and get enough for your region. You need them now and if you want to return to business, then you must have them beyond now. So get use to the tests and make as many as possible for availability and become really efficient in it.

Blood test – serology tests – looking for patients with immunity to covid-19. This may turn out to be the best possibility for vaccine development. Keep in mind SARS vaccine never works for human because it’s too toxic. So back to the basic may be our best way to beat the virus.

Saving lives Ventilators, personnel, and bed resources remain ESSENTIAL. Below is the infection trend of Germany and Italy – almost identical. The only difference – Germany’s hospitals are better equipped with ample number of ventilators. This remains seriously critical. Some of the poorest city hospitals in NYC remains totally under-staffed, not enough ventilators, have no PPE, use a single N95 masks for a whole week (with nothing to protect the N95) and simply they are losing their patients (and the healthcare workers too). So we must pump the resources into these places. Please do. So for all those at risks cities, that is what they need. And they must have as many testing kits as possible to test by sampling, not just on those with symptoms, and must be on those without. Please direct resources to the poorest neighborhood in NYC and to other at risk regions This is very very urgent.

How to sustain the low rate for those with NPI implemented early. I am very happy to know that early NPI implementation clearly shows evidence that it works to slow down the spread. You probably know we are in an extraordinary fragile position. So testing is your good friend. You must test fast enough to off-set any type of potential community outbreak.

I am also very curious how rapid testing can give you one step ahead of the game. Here’s Switzerland, they test the most and their infected graph is very much in control. That is, all of you in states that are doing well, test diligently. You have to sustain it and bring it down as low as possible. Then we will do the next phase.

Protection of healthcare workers So part of my distress yesterday was from calls from healthcare workers who wore PPE and still got infected (and seriously sick). They asked me why. Clearly the paper James and other have showed – surface they touch after they take off their PPE could be contaminated. Simply, the whole working environment they’re in is seriously contaminated. The shedding is so serious. So please do shower – after you take your PPE off and shower at home too. Yes, the water is good for you. But more importantly, the PPE worn –many of them – don’t really cover the face entirely. That’s why I like those ultralight face shields. Use them.

So please be very very careful as you treat your patients. Redundancy is good in the protection. But you must take great care as you shed your PPE off – because that’s when you are most vulnerable..

US Implementation of NPI: Validation (April 13)

Findings/Observations

• Across US, NPI was implemented after March 14, quickly follow by shelter-in-place

• Clear evidence of positive effect of NPI in suppressing the spread: reducing mortality and infection. Timing is extremely important!!

• Interdependencies and cascading effects from neighboring State/Counties reflects parallel scenarios in Europe among countries

• Hence coordinated effort is of paramount importance

• Compliance in contact tracing and quarantine is a must to prevent community outbreak

• Disease dynamic can be fragile when multiple community outbreaks are presence

• Testing remains critical in containing the disease and an important criteria for re-opening

• There is a clear indication that we’re under-tested (contrasting mortality against confirmed infected)

Plot red dots on April 13, June 13, and July 13. Clear suppression during the NPI phase. Most sites fail to contain because of premature re-opening.

A tale of 2 cities: Singapore vs Hong Kong -- Suppress and Lift Strategy

Hong Kong and Singapore succeeded in applying NPI at early stage. From January 26 to March `2, both cities were able to contain covid-19 to mostly imported cases. Note there is no mandatory requirement on business in Hong Kong. Basically, the government leads and every business follows with a sensible plan that works best for them. Singapore's business work plan is a requirement, and punishable by fine.

The two cities diverged when they both experienced imported cases from Europe in early March.

This showcases the challenges in containment and the importance of effective testing and a holistic approach. Community spread is difficult to contain. It takes Singapore 4 months to contain with increase of infection by 95% (from under 2000 to over 44,000 in 4 months).

In United States, New York City, within 3 weeks, bed surge increased by 5 folds

Diagnostic testing remains a serious challenge: very difficult to access sufficient testing kits. High false negatives mostly due to operators' skill. Healthcare workers returned to work after recover from symptoms for 7 days. No testing is available to confirm they are disease free. Many sick patients were turned away since they cannot be tested. Should have been hospitalized if there're sufficient tests and bed capacity.

Serological tests became available: conducted to covid-19 patients who are symptom-free for more than 14 days after a confirmed positive COVID-19 test or after a COVID-19-like illness.

Testing is the cornerstone to stem a pandemic (April 19)

It was critical at the very beginning in January as we tried to contain the virus from spreading, it remains critical throughout now as we try to treat the sick, and mitigate the scope of the spread, and it will forever be essential as we re-open the business and require monitoring and surveillance of the disease to minimize potential disease surge. We need and must have the capability and capacity to do testing effectively and efficiently so that we can perform case isolation, treatment, and contact tracing. And we must sample. While it is good to focus on certain population, we must not forget to sample the population.

I want to post 3 questions:

1. What type of tests do we have and what is the production capacity in producing each of these testing kits for United Stats?

2. What type of lab processing capacity do we have and what is the turnaround time from testing to reporting/receiving results?

3. Who is responsible for procuring testing kits for any given jurisdiction in US? If a site wants to do testing, who should they contact?

I understand local jurisdiction receives some testing kits from the State. Some receive so few that they are in very dire situation. We must solve this testing issue. It is of paramount importance.

Where are we heading? (April 19)

1.Viral survival vs robust transmission. Shortened survival times of C19 at higher RH (75%) and F (94. F) versus continued robust transmission rates in the tropics

We have seen very short incubation time and short disease progression (e.g., German patient 0) and we have seen excessive long incubation and even longer hospitalization and various combinations of such, with diverse disease manifestation and disease state transition. It seems that the virus is very adaptable. If this is the word to describe it, it will find its way to survive and continue its spread. Then, it will be hard to predict how summer will turn out. Each State is different to some extent as to the humidity and temperature. Moreover, the transmission environment varies among different cities. E.g., 2,200 NYC metro transit workers wee infected and 59 has died. We wouldn't think about this in Missoula Montana since people don’t walk bumper to bumper there nor is there any metro running through the city.

2. Public health tradeoffs. I think public health is a very difficult "business" to measure ROI. I am going back to the tradeoffs we discussed two months ago (Feb 14). I copy the exact words I wrote down and add our current situation:

a. Nothing bad will happen and we put too much resources and effort. This scenario in general did not happen. covid-19 did land in the United States and in general, every State felt its existence in different shapes and forms.

b.. Something bad really happens and that we mitigate and make it go away - this is a good effort and result, but understandably it will be underappreciated because noone would know how it would play out without intervention and how bad it is. So successful mitigation is often under-valued. [[people will think it is just (a).)]"

Some citizens (and hence protests) clearly feel this way that the NPI is unnecessary, there're extra beds lying around, extra ventilators, and hence, it is just an exaggeration by public health officials. That is because they themselves have benefited from NPI being put in place!! I truly admire everyone of you who are in public health arena. It is an extraordinary difficult business. For those States who actually did avert the catastrophic full-bloom covid-19 onslaught, now, public health officials are being "blamed" for wasting federal resources and suppressing people's freedom and hurting business.

These are tough choices to make -- let it go and let the hospital beds fill up and get out of control. So people can truly feel that effect, or you have to remain resolute, persevere and know your craft and suffer as a leader so that the citizens don't suffer and that the healthcare system will sustain.

c. Something bad happens and we did not do enough - that is a big fall out everyone knows.

I think NYC sustains the biggest blow. They implemented NPI a bit late. The virus has been circulated for 3-4 weeks before severe-enough symptoms first appears. The city fights back with all they can, with innovation from those large healthcare systems while the impoverished city hospitals suffer silently. Only they know if they have enough beds, PPE, N95, personnel, etc. Ok, we do know because they protest and because their healthcare workers die. So we do know that they don’t have PPE, no N95 and not enough personnel.

NYP has 13 hospitals with 70,000 employees. I understand it is not large by the definition, and it is not nationwide. It is very large to me and for NY State, it is a mighty powerful system. Yes, they innovate with protective shields, use one ventilator on two patients, renovate hospital spaces to increase surge capacities 5-6 times above normal, and they recruit a huge number of labor surge -- 2,800 added to their existing workforce and there will be more coming.

And the healthcare workers some do get thanks during their suffering. Because people realize the challenges of the healthcare workers and they show their gratitude for the hard work and high stress situations. While some may feel left out and being sent in without any protection.

I think it is very important we take path (b) and treat (a) as a real test of how good we can mount a full fight. The lab tests are the first bottleneck (besides all the biological and clinical understanding of the virus). We should lay it all out all sequences of effort and develop a full plan. It is not going to be like a flu plan- because we don't know much about this virus. But we certainly can adapt it.

Detection How do we detect and identify the first case? New York City confirmed the first case of a healthcare worker who came back from Iran. “The patient, a woman aged 39 years, was a healthcare worker and is believed to have contracted the infection while traveling in Iran. She returned from Iran a week before diagnosis with COVID-19 and began experiencing respiratory symptoms. The patient presented to an undisclosed hospital in New York City during which she was evaluated and provided a sputum sample, which was tested in a laboratory in Albany, NY. Although this test confirmed that the patient had SARS-CoV-2, the results will be reviewed by the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.”

So March 1 was her confirmed diagnosed in NYC and March 3 confirmed by CDC. And she came back from Iran a week ago, and she contracted the disease while there. So much time has been lapsed. She could have been tested in the airport a week before March 1, as in Hong Kong and Singapore. How about those who came back from China in January? February?

Without any tests, we don’t know. It doesn’t mean the disease is not here. Should we be concerned? Not if ALL patients have only mild symptoms and no one dies, and no one takes up so much healthcare resources.

But people do get sick, and get very sick which require healthcare resources. 1% of US population in which 20% requires hospitalization and out of that 20% requires ventilators, that would stress out our healthcare systems. Not just ours, but probably all healthcare systems in the world.

3. Sustained response and operations.

I think about the various infectious diseases. For seasonal flu, citizens are advised to wash their hands frequently, cough into the arms and take the preventive flu vaccine. It affects the young, the aged, and those with immune compromised.

For Zika, though can be widely spread, the disease burden is low, may include fever, red eyes, joint pain, headache, and a maculopapular rash. Infection during pregnancy can causes microcephaly and other brain malformations in some babies. Infection in adults has been linked to Guillain–Barré syndrome. And people protect themselves by avoiding mosquitoes. Now there’s Zika vaccine, I don’t know yet if and when it will become widely circulated.

We know very little about covid-19, It stays on the hosts for varying duration, it doesn't kill hosts (rapidly), it attacks hosts in different shapes and forms identifying the weakness of the immune system, it survives on non-living surfaces (remain active even after 17 days on surface of Diamond Princess), symptoms are diverse, and no symptoms at all, can spread during incubation, can spread after post-recovery, can spread without symptoms, already mutated, and patients shed seriously into their living environment. The challenges to the providers, they have to deal with all sort of symptoms. They have to try so many different treatment and combination drugs. It is so very potent in so many ways, yet newborns seem to be ok most of the time. And we don’t have definitive treatment yet, and we don’t have vaccine yet. Many patients have died (however way we want to count it, many lives are lost because of this little virus) and many healthcare workers are infected (and some perished too).

What should public health leaders do? So with all these unknowns about the virus and so much damage in human lives and stress on our healthcare system already, is it unreasonable for our public health leaders to optimize NPI in the best possible way so that they protect the lives of their local population? Absolutely not!! Isn’t that why public health is in place? That these are the individuals who protect the health of the public? So you (the public health leaders) have all the right to decide the best paths forward, because that’s your job and your duty. Everyone can complain as they want, but it is not their duty to protect the public.

I am copying 3 paragraphs below that’s written on the CDC website about 1918, it is very much describing the 2020 covid-19 situation.

4. Attacking those with co-existing conditions. We have talked about this for 3 months now. Just as what China saw, and confirmed by Italy and France, we see many patients with co-existing conditions suffer disproportionally. 324 of the NJ’s 375 nursing homes have confirmed cases of covid-19. When King County Seattle announced the first death on Feb 28, the man in the 50’s had underlying health conditions. The facility’s medical director of infection control, Frank Riedo, said that area hospitals are seeing more individuals with severe coronavirus symptoms. “This is the tip of the iceberg.”

So indeed maybe it’s really just the old who needs to worry? But I am worried about the young with serious co-existing conditions. Healthcare workers show symptoms too, some rather severe. So it is not an old-age disease. So NPI is not a selfish intervention to protect the aged, it is a wise implementation that protect lives.

Learning from the Past (1918 Spanish Flu)

…

"Besides the properties of the virus itself, many additional factors contributed to the virulence of the 1918 pandemic. In 1918, the world was still engaged in World War I. Movement and mobilization of troops placed large numbers of people in close contact and living spaces were overcrowded. Health services were limited, and up to 30% of U.S. physicians were deployed to military service.³

In addition, medical technology and countermeasures at the time were limited or non-existent. No diagnostic tests existed at the time that could test for influenza infection. In fact, doctors didn’t know influenza viruses existed. Many health experts at the time thought the 1918 pandemic was caused by a bacterium called “Pfeiffer’s bacillus,” which is now known as Haemophilus influenzae.

Influenza vaccines did not exist at the time, and even antibiotics had not been developed yet. For example, penicillin was not discovered until 1928. Likewise, no flu antiviral drugs were available. Critical care measures, such as intensive care support and mechanical ventilation also were not available in 1918.⁴ Without these medical countermeasures and treatment capabilities, doctors were left with few treatment options other than supportive care.³

In terms of national, state and local pandemic planning, no coordinated pandemic plans existed in 1918. Some cities managed to implement community mitigation measures, such as closing schools, banning public gatherings, and issuing isolation or quarantine orders, but the federal government had no centralized role in helping to plan or initiate these interventions during the 1918 pandemic.^3"

The Virus and Its Damage

This is not like a queue with a Poisson interval, where the death is spaced out over a reasonable period and the sick is coming in on a regular controllable fashion. This is an avalanche of infections and deaths, all jammed up at the very fat head (in distribution, we talk about the fat tails, this is the opposite),

I concatenate the 3 points from Carter with the 7 points I have - People must realize - (1) the extraordinary public health interventions (NPIs) that have been taken to reduce disease transmission; (2) the striking variation wrt to the impact (deaths per million population) of this outbreak on different areas across the US; and (3) the likely reasons for that variation. (4) the deaths occur rapidly within a short period of time, (5) the sick requires an extraordinary amount of healthcare resources and acquiring of outside field facilities and dorm/hotels, (6) and many healthcare workers are severely affected by it. It is impossible to compare it to seasonal flu since (7) we know so little still about covid-19. (8) We still cannot quantify the symptoms properly, nor how the disease manifests through various pathways. (9) nor there exists any definitive treatment, not to mention that (10) we don't have a formula for vaccine yet.

Reopening (April; 26 2020)

Reopening

Reopening in a complex subject since there is still no definitive treatment nor a vaccine to protect everyone. I have done some tradeoffs analysis, with lots of numbers and graphs again. … This is based on the hundreds of models I ran for different types of business and also on the ground observation.

The first class I taught at Columbia University was “Facility layout and design.” It focuses on the best layout which minimizes congestion, collision, travel distance, path crossing while maximizing efficiency and safety in loading and picking. This works well for many companies, even for hospitals because we can see lots of foot traffic in and out of various rooms that are unnecessary and paths crossing in ED where it creates confusion for patients. I analyze facilities for each of the business and determine how to minimize the infection risks for both clients and servers.

Tradeoffs: The key is to balance the number of infections it may occur (infection surge) versus the economic calamity that the pandemic has caused. In the absence of a definitive treatment and medical countermeasures for prophylactic measures, NPI of systematic social distancing succeeds to slow down the overall infection and allows our healthcare systems to treat patients and mitigate mass casualties in the first wave of covid-19.

As we design the re-opening plan, we must

(a) prepare for a potential second wave,

(b) maintain and sustain the overall infection at an acceptable and manageable level that our healthcare systems can take care of. [[Recall, you want demand < supply at all time. Granted, your supply may surge, but clearly you can’t afford 6 folds again.]]

(c) resume clinical care for the population in addition to dealing with only covid-19 patients.

I will first put down healthcare in terms of what’s needed. This will be followed by the various types of businesses, and then on-the-ground situation.

1. Healthcare

Agile workforce

• There is a need to cross-train healthcare workers so that the provider (skill) surge can be fulfilled in time of needs.

• This is critical given the diverse disease characteristics and manifestation of covid-19 patients (or for future pandemics)

• Care team knowing how to handle multiple co-existing health conditions is critical.

Agile hospital environment (physical)

• ·Advantageous to have an adaptive environment with ample number of isolation-ready wards. Agile design healthcare environment gives us rapid hospital surge and protection capability and capacity. [[think rapid re-configuration of clinic layout]]

• Need sustained covid-19 type wards to ensure timely suppress of any re-surgence of covid-19 patients

Local stockpile

• Must understand normal day-to-day utilization, and project surge needs and vendor options

• Local stockpile of PPE, N95 face masks, surgical masks. Safety-net and city hospitals still need federal SNS support, or stockpile at the state level.

• Re-use and sterilization are critical. Remember the environment, remember there is never enough resource, resources are not unlimited, so we can’t assume we can produce everything from scratch at any time. Conservation while maintaining good sterilization is critical.

• Think re-positioning, as in med-kits.

Strategic testing – cannot forget about sampling

• Critical: a significant ramp-up in testing is needed as we think about reopening.

• Optimal testing size: My analysis shows that a 3% per day strategic testing (with sampling) gives us a good/optimal surveillance knowledge and confidence in monitoring and re-opening.

• Optimal pooling size: Optimal pool size is under 10 (I have the optimal size for different disease prevalence). Must be smart in all these and cannot be ad-hoc nor guest-work.

• Sampling is a must: Must test beyond vulnerable population (nursing home, under-served population, and healthcare workers). Please we need sampling. You can come up with million scenarios why.

  • E.g., it is not the elderly who is spreading the disease since they are confirmed to the facility. It is the agile family members who are busy traveling with work and life and spreading everything around rapidly as they move around. So are the workers.

  • E.g., Italy’s spread to France, Germany, Spain etc was due in part to Spring break and all the university students. At the end, France universities had to quarantine 1/3 of the students, even though they didn’t close schools at that time. Recall, Germany was perfectly ok until the neighboring effect kicks in.

• Diagnostic tests: Diverse PCR tests are available, need to do comparison to better understand any difference among the different modules (production time, cycle time, throughput, reagents availability, accuracy, etc). Need to reduce false negatives (mostly operator dependent, too large pool size) and false positive? (what is the cause?) Need to optimize the testing kits so as to distribute accordingly to cover the US strategically.

• Home testkit: LapCorp take-home is available only to those eligible and have prescription for test from a provider.

• Serologic tests are used for post-recovery covid-19 patients to determine immunity, and for uncovering asymptomatic patients. How accurate are these tests? How do we compare? Only Mayo has the neutralizing antibody tests.

• Immunity to disease: Numerous studies and countries have reported re-infection, post-recovery shedding, etc. What does it mean to have antibodies?

• Hospital: For now, as precaution, test all inpatients in the hospital, ED patients, and all outpatients who are having procedures. Healthcare workers, test both PCR and serologic tests. Do we have enough resources to cover all these?

• Set up a standard surveillance program: as in seasonal influenza programs.

• Data analytics: We must analyze all the test results in a systematic way.

Patient care

• Rethink future (standard) patient care, more tele-health, remote patient monitoring, ability to share tele-resources across States. Perhaps finally successful take-off of tele-health overcoming the billing and licensing hurdles. Need to remember rural and under-served population.

• Measure outcome and cost savings. Telehealth is more timely, efficient, cost-effective, and equitable. Is it safer and is it of better quality?

• Visitation: remote chat, allow patients to “talk” to love ones late in the evening. Could make for happy patients, even if they cannot see family members physically. This can be extended to peaceful time. After hour chats.

• Face masks should be a must for all visitors for infection control (e.g. Hospital acquired infection), not only for covid-19. This can setup a good habit for citizens.

Healthcare worker safety

• Add face shield as routine infection control.

• Routine requirement: no scrubs to be taken home. Scrub on shoes

• UV disinfect on a regular basis in hospital

• Hand washing – some healthcare workers especially those with eczema are having a hard time with frequent washing and use of sanitizers. Some doctors -- the skins on their hands are broken into pieces. And some are developing face mask dermatitis.

Emotional/ psychological / mental health of healthcare workers

• Extremely critical as healthcare workers were traumatized by the extent of sick and dying patients and the chaotic unexpected health conditions and events of covid-19 patients. 24/7 hotlines to advice from workplace emotion to personal issues must be provided.

• Auxiliary support of childcare and home care for elderly should be considered.

• Emotional/mental health of providers is one of the most critical issues related to our nation’s healthcare resilience.

[Citizens need this also, since the worried-well are very worried over many different types of issues.]

Clinical care and Data Collection, , identify vulnerable population and health disparity to optimize outcome success

• Intrinsic health disparity: covid-19 attacks patients with co-existing conditions. Uniformly under-served population and minorities are affected at higher proportion and also with higher mortality, along with the elderly. Closing the gap is a must.

• Diverse symptoms and conflicting treatment results. It is critical to perform treatment outcome prediction to analyze what treatment work best for what type of patients, demographics, disease characteristics, etc. It is also important to uncover the factors that can predict which patients have poor prognosis and hence provide early intervention to prevent death.

• Ventilators seems like numerous complaints about some new (rushed) ventilators that are not as high quality as expected. Not all ventilators are the same. Proper administering is critical. National statistics show more ventilated patients die (in New York, 20% of hospitalized patients vs 65% ventilated ones). These patients tend to be sicker also. Require detail analysis of all patients and the entire care process.

• Data wish list and critical analysis with the diverse disease symptoms and equal diverse medical care and treatment, it is of paramount important that we analyze treatment outcome to delineate what treatment works for what type of patients, demographics, co-existing conditions, care characteristics, and personalized genomic. I understand there are also contradicting argument regarding the lung and lack of oxygen, diverse blood clot throughout the body. We don’t have a lot of time since we have to prepare for the potential second wave. I am eager to perform the analysis whenever there is patient data and treatment cohort available. Recall you should not worry about the size of the patient population; we are ok with size. Many of the methods are not statistical-based and hence are not bothered by small size. The analysis should be continuous and be adaptive. With health disparity, it should also be incorporated along with health gaps and disparity data so as to have a fuller picture on the care discrepancies.

Part 2:

2. Social Distancing and Business Re-opening

I have completed hundreds of models and facility layout design to better understand how we can maintain good and safe distance from each other and for business to open.

Grocery stores: The grocery stores have been really busy here and it’s bumper to bumper already. Even last week the experience was not optimal – the social distancing does not work very well. Aggressive customers simply forget to keep a distance as they wait at the checkout stand. This man kept moving so close to me even as I kept moving away, and I see that I was not alone. This weekend is even worse. The lines were so long – it was not efficient. We can clearly help them optimize – that’s my job and I did a quick time-motion study while waiting in line to optimize their queues.

Nationally, dozens of grocery store workers have died and many more are infected and some dying too. Recall in Erie Buffalo one employee in a grocery store had hepatitis and it triggers 50,000 potentially exposed customers to go to a drive-through for the vaccine? [[two dosage, first one was a walk-in and was a disaster, too long waiting in the cold because of distancing requirement. We helped them with second dose with a drive-through design and optimize their resource and it worked quite beautifully.

Grocery workers are of high-risk. They have so little protection. We must protect them. Some stores feel that it’s time to ban the customers from coming inside.

My model shows that those small mom-and-pop ones really do not have enough space to allow customers to come in and move around, without exposing workers to higher health risk. They need to take order from customers and just pick out the grocery for the customers.

Strategically, the bigger ones can handle this logistically very well. But they are not currently. Even the Farmers’ Market in Atlanta, the one I go to, the customers appear to the rather aggressive. There has to be a way to manage. There is hardly 6-foot distance at the checkout lines. And since the lines curl back into the food aisles, they clash right into other shoppers.

Just as the fire code used to restrict the maximum number of people who can go into a place, we need to do that for the grocery stores. We must. I would say 36 square-foot for a family. [[But mathematically, clearly it needs a bigger circumference. You put yourself into the center, and then you draw a circle of 6 feet. That’s your comfort zone. It is a ball, a radial spacing, and not rectilinear.]]

Please be sensible and ensure this the space-distance density model is being implemented. Otherwise, the workers will be like those in the Tyson meat factories. Also please ensure workers have good protective gear – face masks, gloves, etc.

Citizens must use face masks. Some of them so weird, they wear gloves but no face masks. And those with face mask, over 50% use it wrong (covering below the nose).

And I see numerous litters of gloves, face masks and swipes in the parking lots.

Singapore allows only one household member to go out at one time. So there’s no more family-type activities. I will give you a summary on Singapore and Hong Kong in a separate email.

Restaurants: The 4-max model per table in Hong Kong seems to work rather well. We CANNOT afford to have 10 people in a table. Contact tracing is a 3-generation effort. So, 4x4x4 is a good size to track, but 10x10x10 is far too big. [[Please it is really easy to do contact tracing on the computer, but it’s the whole physical restriction of healthcare resources we need that we must safeguard.]] Recall, you need isolation and quarantine. So you will run out of space if you allow such big group size. It’s really hard to control infection.

In my model, the infection growth is so steep (for just one infected customer) that it is clear we cannot afford such large group size. Please advise your leaders to be prudent. I think restaurants are big businesses (consider 80% of Atlantans eat out), so if they can make the place safe, then it can be a very good experience with minimum infection to worry about. And it will help our economy. And of course there is always take-out.

We better try it now or else we may never know if it works or not.

Again, tables 6-8 feet apart.

You have seen the Air Force Academy graduation how they space out everyone in a 6-foot spacing grid. That’s the same as the car factory workers eating lunch in a grid. It does work, however odd it may look. For now, this is our best deal.

Other service like hardware stores, bakery, etc: They can play it very safe through 6-foot social distancing and follow all the hygiene. Bakery can have very dense traffic and they need to restrict how many customers can go in. Hardware stores have regular customers and they seem to spread out quite well during the day.

Big department stores Walmart, Target, etc. They are essential and they are doing their best with logistics. Many of our students work in these places and they know how to optimize.

I think line controllers are needed in grocery stores and these big department stores that people do shop regularly.

Outpatient clinics: primary care, urgent care, and some specialists can open. But dental, ophthalmology cannot. Some of these doctors have talked to me and they understand the specific risks and they agree they can’t open yet.

General Businesses I model the general business where people come in 5 days a week at a regular time like from 8-5pm, 9-6pm, 7-4pm, or 6-3pm. And I replace it with 20% telework, MWF and TTh schedule, and staggering to minimize contact and maximize social distance success, it’s a great saving of over 30-50% reduction in health risk. So people should be encouraged to work at home. And at work, optimize the cubicles to ensure those coming in will be at least 6-foot apart. General business will help restaurants, and hence a significant impact to our economy. [[Recall Carter put healthcare, schools, and food/restaurants as the top economy be impacted. But schools are fine in this digital age.]]

Malls is a hard one because the restaurants can certainly open, and probably the business too since the foot traffic is not so high. But it is hard to control and it is a very confined environment where people do stay inside long. So it becomes big group gatherings and the model suggests them to be closed for now. I wonder, how can we allow the food business to operate without the other parts open. I cannot tell how. But it is doable.

Food service -- it is important they use face-mask, gloves, and face shields. Plus all hygiene that must be in place. The protection is two-way for themselves and a good practice.

Soft goods -- clothes, etc. I don't know what the current practice is, but as I model it, 30 minutes from one person to the next is a very bad idea. It seems gross. It is bad even for regular time. I think this is how it should be done, just for hygiene purpose, even if ti is not covid-19.

- There should be a designated place where all the items that have been tried on should be hung and let the air out. And this holding area and materials should be screened by UV for disinfection. The clothings can then be returned to the racks after x-days (where x is the safe number), And then they can be accessible by future customers.

I think airing them out and disinfect areas (which they have to do anyway) is critical. And I need x > 1. [[2 is acceptable and reasonable.]]

Hotels some hotels are used by hospitals for contact tracing and isolation. Some use to house homeless population. Some housing foreign students who have no dormitories to go back. Hotels’ livelihood depends on travel, air transportation, business activities, conferences and big events. I have modeled many ways for conferences and big game events. We can’t control how people move around in these large events. So they cannot be opened yet. Any big groups of such will become source of community spread and intra/inter state spread also. Please hold off from resuming these activities.

Schools should remain close for the remainder of this academic year. They are essential in lowering the overall community risk. But we must keep the students busy (intellectually and physically). I think we can. Under-privileged population needs assistance in hardware and better internet access.

• Daily sewage tests for covid-19 for bio surveillance and early detection

• Daily randomized diagnostic tests on students

• Split students into two groups and stagger classes as follows: First group attends class on Day 1-3, off from 4-14. Second ground attends class on Day 8-10, off for 11 days.

• Plus all the other environmental and hygiene and safety precaution suggested by CDC.

• Kids are good spreaders! recall our discussion in February.

Non-essential services: hair salon, nail parlor, barber shops, tatoo parlor, gyms, bowling, etc.

Hair: I discover I have no idea how hairdressing business work since with my wild curls I have the fortune to never go to one. I asked my husband and he told me the simple barber shop he goes to takes about 20 minutes to cut his hair. And I ask some women about their hair – that’s much longer like 2 to 3 hours.

It’s unclear how to safeguard both parties in these places. Men apparently need to cut their hair very often, maybe once a month? and women do their hair often too(according to the little survey I did for just about 100+ people). With 20 minutes of very close contact, and there is very little ability to disinfect, the spread can be serious. But then for women with 2-3 hours in a salon, that’s even worse. This is a risky business. I deduce that the fume from chemicals can also accelerate spread of diseases. So in my model, no matter how I model is, it does not give me a very safe implementation. I do not like the results.

Nails, tattoo: I do not know why anyone needs to go there. I am probably the worst person to know since I again have never gone to these places. But youtube has them all. Apparently even the Texas mayor went to the nail salon during the stay-at-home order. Nails are the dirtiest with tons of stuff inside. Tattoo, blood and needles. They are very unsafe in many ways. And they are in such close contacts also.

These types of business contribute not so significantly to the economy. By allowing them to open, it means the employees can’t file unemployment if the employers choose to work, even if the paycheck is low. It’s a strategy to reduce unemployment claims, at least this is what my model shows and the model reveals that their opening is not a means to help with the economy. The tradeoffs in safety is significant. I would advise against it. I am bias clearly because natural is what I love. But with all these chemicals and fumes, it won’t help with their lungs if they really get infected.

I am all for opening restaurants, but not these types of places.

Nightclubs, bars, karaoke, vaping / cigarette parlor The risk is too high to open.

Theme parks Too large crowd gathering.

Movies & plays: drive through is good. The walk-in type should wait. In person theatre demand is in decline anyway. Broadway shows have to be closed too, the seats are so so packed.

Air Travel: This is a very sticky one, we can’t open now. Airlines need to figure out a way regarding air circulation. Require face-mask and more on air circulation from outside.

Conferences, games, churches, etc… they need to wait.

How should we response? April 29

1. Timing of intervention is of critical importance. When to apply NPI truly makes a huge difference in terms of the total number deaths and infections that we can reduce. If NYC closes schools and telework one week earlier, that would have reduced 22% of the infection and respective deaths. Timing is everything and hence this is the execution that must happen, decisively and timely. Perhaps politicians want to wait because they are hoping some magic would happen and all of a sudden, the virus would miraculously disappear. Viral biological phenomena do not work as such, and hence either they wait long enough to act (when they have no choice), or they act early to avert mass casualty and take charge. Furthermore the downstream of economic impact can only be better understood if they anticipate an early action so as to control the course of the pandemic. Once they miss that part, they are behind the virus and basically everything becomes responsive.

2. Accept the pandemic risk early on and test rapidly. The New York City first case (or you can use any first case anywhere) came back from Iran, became sick, and went in to request covid-19 test since she's a healthcare worker and acted sensibly. She could have been tested at the airport upon return and detected a week earlier. For one week, that would mean hundreds and thousands or tens of thousands of people she had interacted. You can imagine the disease tree how fast it grows. Testing was handicapped early on and we're still trying to catch up. Testing remains critical and you must test fast enough to suppress any community spread. [[Clearly she is NOT the first case. First case would be in early January, if not late December.]]

3. The severity of this pandemic cannot be overstated. The number of deaths occur within a very short period of time is huge, and everyone, whether they are scientists or politicians cannot deny this fact. This is a highly contagious infectious disease in which there is no definitive treatment, no vaccine, and is extremely health-resource intensive. It is extremely challenging in every aspect of the response effort. And hence, early intervention is important because we need the time to ensure the disease burden does not overwhelm our healthcare system max capability and capacity.

4. Letting covid-19 run its course without mitigation is not doable. If what happens in China and Italy did not give us some sense of severity, then perhaps nothing can. If we did nothing, many many people would have perished within a very short time. Herd immunity would not happen quickly many people would die. We must understand, or rather the public must understand, the NPI implemented have saved their communities, so they didn't become another NYC, another Lombardy. Yes, the results are remarkable. Yes, the attack rates speak volume! Even in rural areas, they need not be like NYC to feel the severe health burden. Remember I mentioned about 1% of the population infected. I mean really 1 percent is all that matters (sufficient worries and sufficient to overwhelm our healthcare system in any part of the country). A community of 100,000 where 1% is infected and 20% needs hospitalization. That's 200 and if 20% of them need ICU, then that 40 people. Do they have that resource? In a rural community, some may have 15 ICU beds? and we need 40. So the healthcare burden is felt acutely by every community, even though 200 patients would mean so few for NYC.

5. Re-opening. I urge the policy makers to think hard and long what to do now as everyone seems to feel the urge to go back to "normal" pre-covid-19 period. We must implement all social distancing steps to safeguard each of the communities. China Wuhan was locked down for 76 days. And now as they re-opened on April 8, they continue to resort back to quarantine of individuals (14 days and strict going-outside guidelines) who are exposed within a community spread. We truly need good social-distancing steps in place. And we truly need our testing capacity. We can't be short of testing kits, we absolutely cannot. We must be able to test rapidly whenever there is a known community case so that we can blanket it and extinguish it.

An interesting part the politicians can learn -- perhaps from Boris Johnson who becomes more appreciative of NPI after his own personal experience with covid-19. In the same token that one doesn't need to be poor to have empathy to the poor, hopefully our leaders can lead in such an unusual time. The next pandemic may come in another 100 years and we won't witness it ourselves. Let's hope we can do well with this one, prevent and suppress the second wave, succeed in finding a vaccine, and be able to mass dispense to prophylactic the population.

6. At risk population. Indeed, we absolutely cannot lock up the nursing home or LTC population and let the others without any protection. I think we can easily understand why that won't work.

Mathematically, I did model the activities of these individuals, they are not very mobile like the healthy and well, so they don't contribute a significant percentage of infection. No, we can't sequester the vulnerable population, it won't work. It is the non-vulnerable population that spreads and spreads very effectively.

It is the workers in TLC sites that spread the diseases rapidly. And it is the community-type living quarters that put a high risk on these elderly residents. If we make them into smaller dedicated PODs -- i.e., have a small team of workers take care of a small group of residents. So break them into small groups. Then we can reduce infection very effectively.

7. Herd immunity -- Indeed, we can't afford herd immunity. From my models, across the country, about 48% -85% will be infected before herd immunity can reach. And hence many will die from covid-19. You are not talking about covid-19 people dying, you are talking about 9.6% - 17% of Americans require hospitalization, that translates to 32 millions to 56 millions of Americans who need hospitalization. Remember, not a single city in the US can handle even 1% of infection, not to mention about these many! What it means -- you have even more people dying -- people who have no covid-19 also die too because their medical care is being compromised. More healthcare workers are going to die too, because they're totally overwhelmed by the avalanche of very sick people who need medical care. The rapid spread ensures a very fat head pouring into the healthcare system -- everywhere - either it collapses the systems rapidly, or he government is going to order no healthcare for any covid-19 patients, Don't even think about this route, there's no way out except a lose-lose situation and it will tear this country apart.

How to combat covid-10 effectively (May 5)

There are truly multiple challenges in fighting this pandemic. We do not have sufficient diagnostic tests, we do not have a definitive treatment, and we also do not have a vaccine to protect the population. Hence NPI is our best first layer of defense, allowing us to protect all citizens except those critical workers. We see a disproportional high infection among healthcare workers, subway workers, meat-packing workers, and just about anyone who works in large groups and exposed, from the best protected to the least protected. Noone is spared. This is text-book -- this is everything an infectious disease expert knows too well.

Back on March 13, we already know what would happen now. "The fact is, those States with NPI in place now won't have exponential disease spread and people would say, what a waste of all the effort because there's really no disease anyway. Being able to avert the disease spread is then being ignored and NPI effectiveness being minimized."

Let's look at what can be done with testing that is targeted and succeed to contain:

Hong Kong -- they test everyone who travels back from anywhere in the world. They isolate all positive cases and they quarantine and monitor all negative cases. They contact trace all these individuals. They finished testing 3,600 people+crew on World Dream cruise within 24 hours back in Feb 4, and upon disembark, they monitored them for 14 days and contacted trace everyone.

So they avoid/minimize any community spread by stopping everything from spilling into the community. And they added the NPI layer on top of it, closing schools, and having tele-office for government services. With Government service announcement in place, all business follows suit. People still eat out, people still go to business, but with 80%+ service being tele-office, those workers who must go to work can practice social distancing. And yes, > 95% of people wear face mask, in fact, everyone does. The curve you see below, those increases were due to returning citizens carrying the disease with them. And with one potential spread (in a local bar filled with visitors), the city asks citizens to only have 4 people for each gathering. This allows them to conduct effective and efficient contact-tracing.

South Korea - started a little differently. The major spread was from a church gathering that quickly ballooned the infection within a very short time. The remarkable part is the rapid testing they're able to mount - 10K per day within that very targeted location. Basically they're catching just about everyone who may be infected and isolated them. As you saw in the news, early on South Koreans were eager to get face masks, and the government stopped them (even made it a crime), for fear it would create shortage to protect healthcare workers. Now, the officials apologize, and they're allowed to use facemasks and clearly everyone is masked.

Systems approach We all know that fighting the pandemic effectively requires a systems approach. With NPI easing, we must shore up our ability to test.. Targeting testing doesn't work anymore because of the widespread of covid-19, and hence sampling becomes important. Social distancing, masks, and everything we have been discussing about how business must implement safety guidelines to minimize infection is critical and essential. If not for the citizens, it will be for workforce protection. Either way, they (the business leaders, and the political leaders too) want business continuity, yes, there're guidelines to make it happen, precisely protecting themselves from customers, protecting customers from customers and protecting customers from their own workers. It is a graph with all nodes connected. We can't dispute it, these are clear facts. Once they realize that, hopefully they have good incentive to make all safety process happen and follow with it with the best compliance. Everyone contributes to the effort, it is everyone's business, everyone is a dot in the system and every dot counts.

Yes, if we have sufficient testing kits, we can do sampling and that could serve as a biosurveillance layer beautifully. With that, it adds onto the syndromic surveillance, all the workforce protection steps, and citizen masking and social distancing, and we can protect better and in a more effective manner. Remember, every layer matters, and hence we must see that it happens in all jurisdictions.

Extraordinary Time (May 5)

This is an extraordinary difficult and trying time for this country -- emotions are running high for both the enforcers and the citizens.

This is such a strange contrast with my time in Japan for the Fukushima radiological disasters. I was with the people who're displaced by the nuclear disasters. I had to provide instructions to everyone on what needs to be done. Amazingly, they all followed the instructions. I was shocked and I thought for a moment, how would it work in US? I couldn't imagine because simply the cultural difference is stark. Because they're able to respond in a unison manner, it saves more lives and minimize the severe downstream health effect, even though over 25% people were already affected. Nonetheless, it stopped right there. But emotionally, the wounds are still painful and open.

Emotional wounds of the healthcare providers, the family of the loved ones who have perished because of covid-19 is going to be so high. So I hope citizens can do their share and realize it is part of their responsibility that they are protecting themselves and others by wearing a mask. It is just a simple piece of cloth, it's not like a metal armor. It will be good if they can see the good with a little inconvenience. The tradeoff is obvious and the time is now to act. There is no looking back. The little virus is not going to look back, but march forward. Either we are to win or level with the virus, or we can let the virus win.

People who refuse to wear masks do not know/care that they are affecting others, affecting the whole country. Do they consider we defeat the virus if we lose 65,000 lives? Or do they consider we defeat the virus if we could have achieved at 20,000? Or is it ok for 100,000+ to die? As long as it is not their very own lives?

What is happening to reopening (May 6)

State vs county-city approach: Looking at Georgia, on April 24, only one county in Georgia - Quitman -- satisfied the 14-day zero-nadir - 14-day no infection increase criteria. Although opening business appears to be a state-wide matter per governor, strategically, safe-opening risk-based approach seems to be better at a county-and-city level. Simply the disease spread is heterogeneous, so are the risk factors of human, environment, socio eoconomic, and behavior. Most importantly, the disease source (# and start-site) is very different to begin with.

As of today, there are only 4 counties in Georgia satisfying the 14-day zero-nadir requirement. Here are some facts to ponder. Please focus on death, since positive cases are dictated by testing and there's a severe shortage of tests plus and the results take too long to return (> 5 days) unfortunately. I am including only a few graphs. They are far from ready to re=open.

About 20 people contracted the virus at funerals held in the same funeral home on February 29 and March 7 in Albany. By April Albany Georgia, a city of 75,000, became one of the highest mortality per capita in the world.

City of Atlanta: To put things in perspective, patient 0 was declared on March 2 from a father and son returning to Atlanta from a trip to Milan Italy. However, the individual who died on March 12 in Atlanta contracted the virus in Albany's funeral home on Feb 29. Basically, community spread has occurred in Atlanta already before an imported case from Italy, yet the gentleman on March 2 is still listed as patient 0 index case.

Strategic re-opening: looking at the disease trend across different counties, it becomes clear that if one can open based on county performance, we can arrive at very safe re-opening level. So I advocate risk-based safe-opening approach based on performance of each county or city, taking into account the inter-dependencies and cascading effects of adjacent counties and cities and also business travels. I think it is a win-win strategy for us all. The governor clearly sees the danger of his action -

Kemp Warns Of Potential For Another GA Coronavirus Outbreak

https://patch.com/georgia/atlanta/coronavirus-update-atlanta-tuesday

Sequestering the aged and the medically fragile: This is happening to us here in Georgia, since there is a final push for all schools to re-open. There is a petition in place now that seeks input from various schools. At least, university is done for now. I don't see why they would risk getting students and faculty on campus for the summer. But one never knows.

Disinfection: Clearly disinfecting surface is one of the important steps we have advocated. I think the UV disinfection is great. At home or in business where they are not using UV approach, we need to advise them. There is already increase in volume to Poison Centers because people are using too much of toxic stuff at home. Simply natural things are much better than those highly toxic ones. When NAE sent us to India for extraordinary engineers interaction (that was 10 years ago), I recall sitting in the dining hall of this beautiful marble palace-like hotel, and as I ate my breakfast, they're spraying stuff right in front of me. Well, I got food poisoning right that night. I was told, 20 years ago, 1/2 of the US delegates(about 10) had food poisoning. For our group, I was the only "lucky" one.

As people start to clean and disinfect, we may see some problems since we expect people to know what to do. I think CDC can and should provide some guidelines as in combating Zika (on what to spray and how to spray).

Face-masks: I do believe it is easy to teach citizens how to use a face-mask properly. CDC teaches people how to wash their hands, can't they just put down a picture on how to use a face-mask? I found some very nice ones. But if one needs it to be official, that's what CDC needs to provide.

I believe CDC needs to put out all the recommendations in a clear manner. Individual governor can have his/her say regarding what to do and what steps to follow. But at least, they can refer to CDC website for these basic steps. It gives the public some comfort.

June 2020

Strategies for Vaccine Prioritization for Effective Pandemic Response

Mass Vaccination

• Critical for population protection

• Challenges:

  • • Time to design: Pharmacokinetics, safety, efficacy,

    • Limited amount: production pipeline and throughput, global demand

    • Who to dispense: risk level, effectiveness, potential ADE

• Mixed strategy

  • • Start with prioritized vaccination to the high-risk population

    • Switch to (non-prioritized) general population at some point

    • When to switch? Determine optimal switch trigger that results in minimum overall attack rates and mortality

Guide policy and operations

Challenges

• When to switch from prioritized to non-prioritized?

• How to incorporate realistic dispensing operations (vaccination / treatment operations) within a disease propagation framework?

• How to incorporate limited and interrupted resource (vaccine and time)?

Incorporate ALL within a single modeling-computational-decision framework

Methods

• Disease propagation model to characterize the pathogens, track infection and deaths

• Network dynamic to model individual inter-connectivity

• Stochastic queueing model to reflect dispensing/vaccination operations

• Math programming/optimization to model the switch trigger* based on vaccine inventory

Introduce and define switch trigger:

Definition: Switch trigger: % of vaccine dispensed to high-risk individuals first before general dispensing

Objectives: Minimize attack rate and mortality rate during the course of the pandemic

A City of 3.3 Million

• Contrast different vaccine supply levels: 10% to 50%

  • • [[will have all the levels in the final results to explore the break points.]]

• High Risks: 19.3%: 3.0% healthcare workers, 16% elderly with co-existing conditions, 0.3% patients with underlying disease conditions. [[Can include essential workers, e.g. nursing home workers, meat-packing workers, and more.]]

• Some Parameters:

  • • Course of potential wave pandemic: 90 - 120 days

    • R₀: 1.0 - 2.0 (vary over the course of pandemic)

    • Vaccination start time: no delay - 3-week wait until arrival of vaccines

    • Initial infection: 10 active infected individuals, or 1% of active-infected population

    • Number of dispensing sites: 40; operations efficiency; triage accuracy; finish vaccination in 10 days

• Vaccine Parameters:

  • • 2 doses per individual (21 days apart)

    • Efficacy is 95%

    • Dispensing is based on personalized prediction through vaccine immunogenicity study (hence high efficacy). In such an approach, we will take the DNA of an individual and determine in real-time if vaccine is beneficial to them or not.

    • Anyone with positive molecular tests or positive neutralizing antibodies will not receive the vaccine

    • Since it takes so long to induce immunity, regular strategic testing and isolation and quarantine continues during those periods when vaccines are dispensed.

Observations (only 10 active infection to begin with)

• Giving vaccines to > 80% of high-risk groups result in the highest attack and mortality rates

• For a given vaccine inventory, the optimal switch trigger significantly

  • • reduces 47%-55% infection (attack rate 2.52%-2.88% vs 5.58%!)

    • reduces 37%-47% mortality (0.077% - 0.09% vs 0.1444%)

• Virtually no difference between 40% and 50% vaccine inventory

  • • Herd immunity is achieved with overall attack rate of 2.52%. So 2.52% infection + 40% vaccinated = 42.52% gives the herd immunity. More vaccines (50%) does not change the attack rate.

• The switch trigger depends on vaccine inventory levels, disease prevalence and spread characteristics, time to dispense and efficiency of dispense operations.

Observations (1% active infection to begin with)

• When vaccine inventory level is > 10%, giving vaccines to > 80% high-risk groups result in the highest attack and mortality rates

• For a given vaccine inventory, the optimal switch trigger significantly

  • • reduces 9.3%-11.7% infection (attack rate 35%-40.3% vs 39.6-44.4%!)

    • reduces 6.2%-15.2% mortality (1.22% - 1.45% vs 1.15% - 1.23%)

• Virtually no difference among 30%, 40%, 50% inventory

  • • Herd immunity is achieved with overall attack rate of 35%. So 35% infection + 30% vaccinated = 65% gives the herd immunity. More vaccines (40%, 50%) does not change the attack rates.

• Herd immunity requires 65% protection vs 42.52% when only 10 active infection at the start of the pandemic

Findings

• Limited amount: When there is not sufficient vaccine to cover the entire population, strategic vaccination is a must for best population protection

• Severity: The more severe the pandemic, the earlier the general vaccination

• Timing: Vaccination must be done in a timely manner

• POD operations: Optimal dispensing performance is of paramount importance

Discussion

• Computational decision support environment, RealOpt-VacOpt©

• Given outbreak biological characteristics, supply level & timeline, treatment/prophylactic operations, and risk factors of population, determine the best vaccination strategies

• Evaluate trade-offs faster to save more lives and better utilize limited resources during a pandemic event

• Will run it for every community with specific demographics of high-risk groups and disease spread risk

  • we first optimize the allocation of vaccine across the entire country for best population protection; next

  • we optimize to determine the optimal switch trigger for each location.

July 2020

Determining optimal pool size (July 5)

I hope you enjoy a nice July 4th weekend. I want to share with you some discussion I have with Carter on pooling. You may recall China spent 280 million US dollars to test 11 million people in Wuhan in 10 days using a pool size of 10. I want to know what the optimal pool size is with respect to disease prevalence. Clearly the more wide-spread the disease is, the less the pooling is effective. Keep in mind as you test the community (via sampling), the percentage of positive cases should decrease. If it does not, then you are not taking any action with respect to mitigation after each test results.

In determining the optimal pool size with respect to disease prevalence, we want the pool size that gives the smallest percentage of laboratory testing effort. Here is the table and the associated graph corresponds to the effort of testing via pooling. A 0.19 testing effort means you only need to do 19% lab tests to cover the entire population. So for 1 million people, the total number of laboratory tests would be 190,000 in order to find out how many positives there are among the 1 million people. So the lower the fraction the testing effort, the better.

When disease prevalence is >= 30%, pooling has a negative effect (red curves on the graph). The effort is marginal already if prevalence is >= 25%.

With the table, it is easy to see the optimal pool size. For example, for 1% prevalence, a pool size of 9-12 is the best, whereas a 5% prevalence should use a pool size of 5, and 10% prevalence a pool of size 4. Wuhan identifies 206 positive cases.

The decision makers need to use their own judgement in terms of the prevalence. My feeling is that we can deduce it rather well from the pockets of fire at high-risk sites, and then sampling of tests allow for good pooling size to cover a broad group of people in the community.

FDA approved our optimized pool size! The first time!

Means of Transmission

Strategic testing, contact tracing, face-mask, social distancing, personal hygiene, all remain very critical elements as businesses are opening. Some indoor businesses such as bars should be closed. I will show you some data so you can be convinced.

Weather

One thing I want to mention, although it's probably obvious to everyone. Mike Callahan mentioned the environmental factors (bounds of temperature and humidity etc) in which SARS-CoV-2 stays active back in March and asked us to model how it affects the infection across different countries with different weather. It took me a couple of weeks to get the temperatures of countries/cities in the world to start analyzing it. I let the model run for months, it never identifies a place where hot and humid ensures that covid-19 virus does not spread. The virus seems to adapt so well to different places and to different human bodies. And we see more varieties of damages it is causing, including the brain. So much to learn about this virus.

Airborne Transmission

I don't know if the transmission is airborne or not. However, early on months ago, we all know the RNA shedding is severe and is over 70% surface indoor of an infected individual. So, it can transmit so readily regardless if it goes airborne or not. So much saliva droplets come out whenever people talk, so it is a must to wear a facemask. I would recommend face-shield in ALL service interaction activities, both servers and clients - e.g., hair salons, the planes, restaurants, car rides, etc to protect the eyes and the face also.

About face masks, in the farmers' market, almost 90% of people wear facemasks and I see improvement in compliance. There seems to be a renewed concern and belief that everyone has responsibility in this fight. I think that is very encouraging. Of course, I step into another store, Home Depot, and Kroger, barely a single individual uses a face mask, not even the server. I must say this Farmers' market has sanitized wipe, water tape for hand hygiene always (not special for covid-19), something other sites should emulate.

Economic Analysis

I did some economic analysis. Recall healthcare constitutes 17%-18% GDP. Using CMS 2018 data, I put down the breakdown of the various spending.

Counting only the top 3: hospital care, professional service, and long-term, nursing home, etc, this amounts to 72% of our healthcare expenditure.

Several facts and implications (from the models)

Facts:

1. Diagnostic lab results do not come back until 5-7 days later, leaving tested individuals in limbo -- since none of whom are advised to quarantine themselves while waiting. If the results come back positive, valuable time (days!) is lost, and the patient disease tree gets a lot bigger than necessary. Most states haven't been able to do effective contact-tracing. The longer wait leads to bigger disease trees, which require more resources to trace and thus adversely affecting disease containment capability and effectiveness.

2. While these infected individuals are not dying at the same rate as those in New York City, it does not mean that they do not use hospital resources. Indeed, currently the largest hospital in Houston has exceeded its hospital capacity in treating the sick. And Florida, Arizona, and California are experiencing hospital demand surge also. It is expected that they don't die so fast nor at high volume because they are in the age-groups where mortality is low. However, we have seen in many reports the seriousness of the illness and the prolonged hospitalization that these patients experience.

Please recall, for NYP among the 9000+ hospitalized covid-19 patients, 20% died. The death is indeed a tragic loss, furthermore hospital burden includes all patients, not just those who die.

3. The hospitals are running out of PPE (again!), endangering the healthcare providers. Recall, over 95,000 HCP have been infected.

4. The current US infections is over 3 million. There're over 300+ million more Americans whom we have to protect, and hence face-mask, hand hygiene, social distancing, and avoid large indoor crowds is a must.

5. From modeling analysis: If 10% of these infected individuals require hospitalization and the rest (asymptomatic) romp around, they will eventually infect many people, including essential workers, healthcare workers and these will endanger the entire healthcare chain, where elective procedures and other critically ill (non-covid) patients cannot receive care safely and timely in the hospital environment. Accounting for all the cascading effects, this will amount to over 50% of the healthcare GDP. Any way you look at it, this is a far bigger economy than the economy provided by the bar business.

6. Five percent of Americans accounted for half of all U.S. health-care spending in 2017 . These individuals have multiple co-existing conditions and are at extremely high risk. Either their health is at high risk due to the large infectivity around them, or their hospital service is affected due to the high covid-19 volume patients, or both. This endangers their life and also the healthcare GDP.

We need to use the economy to justify the actions we need citizens to take. If they don’t do what is being asked of them, they will endanger not only lives of high-risk individuals, they will also inflict serious blows to the fragile healthcare business, and thus a large GDP of this country. Hospitals in NYC are losing money, and they desperately need to serve the regular patients. The hospitals in these accelerated states have much to learn from.

I don't mean that this is the only way to look at it. I have always argued it from the public health and population protection angles, and I truly believe it dearly. However, the push back is always about the economy of this country. But without citizens engaging and taking their share of responsibilities, and politicians decide sensibly on what business to re-open, they are endangering the very factor (economy) that they want to recover.

7. Most outpatient clinic providers do not have N95 face masks. Their ability to serve patients and open business as usual have been limited.

Challenges in Contact-Tracing

We have designed powerful human-in-the-loop contact tracing tools. It's network, graph theory, and combinatories technologies (ok, I am biased, these are my thesis work). It's large-scale but manageable.

• What are the challenges?

The challenges are multiple folds:

- We need to test and contact-trace fast. With testing results come back in 5-7 days, each individual(who is positive) tree grows rapidly and hence increased burden both for human tracers and with the size of the networks. The longer it takes the results to come back, the bigger that positive tree will grow. And thus it s a huge network to test and to quarantine. (because you don't just trace these contacts, you test them too.) So test results must be returned fast so that the tree (for a positive individual) remains steady. Highly likely it is big to begin with already since there is time between people get infected to when they get tested.

Or between test and results return, advise the individuals to self-quarantine or isolate.

Recall that 1 case in S. Korea nightclub resulted in 80,000 individuals tested. This is a great opportunity to do pooling in this case. And pool size 10 is a good number.

- Europe and Asia utilize mobile technology to assist, triangulation, or the decentralized app. Note that all the European countries have given up on the centralized app because it is extraordinary slow. Germany was the last to hold out and they did give in. Please review the news I sent to you a couple months ago. They are now using API - Apple-Google exposure alert. There is clearly privacy issue and of course hackers and all.

- A key part is data design and clever purging (optimization), scalability, and extensibility. Very much like the SEIF/MIX designed that I have shared in November. And of course on top of it sits analytics decision tools, and visualization etc.

- Privacy and security remain critical, because at the minimum, you will store the cell number. You don't need to store a lot of things. But you need to be able to trigger level of alerts to people in a timely manner, and hence you need that level of communication. Now, it can be like Amber alert (like you don't know who is infected, just that you have been exposed to it). However, that can be bad -- not knowing clearly what risks they are, but yet just you are in the loop of risk may not be too helpful. It can scare people instead of making them feel being helped and protected.

Nonetheless, you can configure it the way you want it (i.e., local jurisdictions can dictate what they want, or should we not allow that, it's chaos now?). Anyway, in Germany local leaders do sit together and decide a national strategy. I think their plan is careful since they did hold out the longest before easing to decentralized approach.

• What is the state of the art?

It clearly goes way beyond the paper-and-pen approach or phone calls. Human-in-the-loop (I want human to be on it so it is automated yet provide interaction and human touch) does include human to call. Once being contact, you can immediately initiate the tree by either the user inputting it, or in the case with the app, it will propagate itself automatically.

Please be reminded that requiring a cell phone means that we will miss some people, little kids(cover by parents or other adults), under-served population, homeless, or elderly. In any case, nothing is perfect. So the API does not cover everything. Human is still there.

• What are the privacy/ security concerns?

If you don't use the API, you have a lot of capabilities to control / manage the type of information you want to store and how to protect it. Nonetheless, because you do need the contact information, minimal information will have to be stored. Furthermore, this is like a monitoring system, so you are tracking people's movement (to some extent), even though you can say you are not, only if there's a positive case will they be notified. But then you won't be able to notify unless you know where they are. So you see the catch.

We have designed an app a few years ago (me and my student) to let people enjoy local arts and culture when they arrive to a place. So people can sign up for the app and they will be prompted things close to you that you can check out. So wherever they go, they can check in and it will pop up interested things, local arts, nature, etc that they can join or explore. Kind of cool, and people like it.

• How do we employ?

You mean deploying the system?

• Who should participate?

I think citizens need to opt-in, so they can be connected to the App or the system. That's one way to do it. Or, we can just initiate contact whenever their cell is close to an infected one.

We don't opt-in Amber alert. But odd, some people receive it automatically while others don't.

• What is the role of the government?

Clearly testing remains the tasks of local government, so they will need to engage in this effort because we can contact-trace if we don't test, and we can't quarantine without governors and mayors to make decisions on the public health strategies. And they might have to work with vendors who provide such systems..

Europe

It looks like some of the European countries actually go with centralized ones, e.g., France. Centralized approach is more a "big brother" approach and citizens may feel being monitored and controlled by the government. In any case, most European countries are using the decentralized approach, include UK (latest decision). Interesting how volatile the decisions are, since a few months ago, it was Germany who was holding out and not joining as they tried to build the centralized approach. Now UK tried and failed and will join the decentralized scheme.

https://venturebeat.com/2020/06/19/covid-19-tracing-apps-now-live-in-germany-france-and-italy-u-k-rethinks-its-plans/

Germany

Recall Germany and Hong Kong co-designed the testing kits early on with results on Jan 17 and being adopted as WHO standard by Jan 23.

The first test was designed in Berlin on Jan 10 by a group of Professor Dr. Christian Drosten (who became very popular in Germany).

There are no patents on the tests. And this has resulted in a boom of local small to medium sized companies (200+) that produce test sets.

Covid-19 testing is no problem. In fact, they have more capacity than needed and some test centers have already closed down. When some location becomes a sudden hotspot they are able to contact trace rapidly and “everybody around" is tested.

- testing takes 4-5 hours in the test lab

- the total time for obtaining results depends on the delivery time and possible queueing. The test centers guarantee an answer within 24 hours,

- in urgent cases, almost immediately.

An app for contact tracing has been introduced in Germany on June 16 and has become available in the beginning of July in all states of the European Union and some other countries. It is available in 20 different languages and can be downloaded for free from many app stores. The official "editor" of the app is the Robert Koch Institute in Berlin, but the app itself was developed by SAP and Deutsche Telekom with the support of 25 different companies, including Apple and Google because the interfaces of their operation systems had to be employed. It is impossible to figure out which type of person did what. The app is based on Bluetooth. Right now about 16 million Germans have downloaded the app.

The app was not really successful, since the infection numbers are very low and the number of warnings are minimal. It would be interesting to see the “reaction” of the app when there is a bigger outbreak or a second wave coming.

But still everybody believes that the app is an important additional tool in the toolbox for fighting the covid-19. People are sure that it will help in case of possible future outbreaks.

A Holistic Approach for US

Yes, actions are needed, and actions are very time-sensitive.

A holistic community-based strategy We truly need a national or regional strategy where everyone marches together. Within a community, if people are marching in various directions, it is very difficult for them to converge to a common goal of R0 < 1.. We have seen actions that have contradicting / conflicting effects.

If asking for a national strategy is too much, then at least each county, each city, each jurisdiction, or each state etc, they must have a strategy that is holistic where actions are all complementary to one another so that they can optimize the achievement of goals and the outcome. It's almost 7 months since we had the 1st imported case, so perhaps we are not asking too much from our leaders to have a holistic strategic plan of actions where everyone can march together and work together.

Contact trace and exponential growth

Contact-tracing by default is not automatic, it requires notification of a positive case and then actions from two sides: a) those exposed to quickly self-quarantine / isolate, and sign up for testing, and start recalling their daily journal of activities and contacts, and b) the public health official to optimize the entire testing process (schedule, test, result, notification) to minimize delay. The public health official's actions require multiple layers of resource and tasks by external vendors. We all know that sadly every layer has delays.

This relates back to the discussion we had a few months ago, is it voluntarily self-quarantine, or a required/mandated quarantine (similar to face masks). To quickly curb the disease spread (lower the R0), it is important to have sufficient compliance/cooperation. With such wide-spread of cases now (because of the mobility of healthy asymptomatic infected ones and non-compliance in face-covering and social distancing, we will need more than 50% to volunteer self-quarantine. (all the actions are inter-dependent and have cascading effects).

For each individual, the growth of contacts is exponential. It will stop faster if we break the network by self-isolation, closing things up, social distancing and face-masking and basically minimize the connectivity of spread. Combinations strategy of the right amount is important.

Turning all these into actions that will work, Each local jurisdiction (start with counties or cities) public health leaders can communicate with the public, with the help of community leaders/influencers to spread the message out, so that every citizen will start self-quarantine /isolate the moment they know they have been exposed to a positive case. I think this part is doable.

It is also possible, as in the local outbreak of Hepatitis, citizens can be notified of disease hotspots so they can self-quarantine (and sign up for tests) if they know they are in the vicinity. It is not for a lack of options, it is that all these have to turn into actions.

Reopening: Predicted vs Actual (July 20)

I want to share with you some recent analysis on re-opening and case escalation. This relates to the April 7 analysis I did to:

• Determine when to re-open

  • At which risk posture should a city/jurisdiction reopen

  • How to re-open (business, daily services, religion groups, schools)

• Determine optimal testing sampling size for disease containment

  • 1% to 5% (The optimal is 3%)

  • Testing accuracy

• Case isolation requirement

  • Use dorm/hotel rooms

• COVID-19 Hospital bed capacity

I want to overlay the current increase cases onto these curves for validation (3^rd and 4^th graph). This offers a means to validate and quantify the risk posture of each site at the time of re-opening.

Briefly, the first two graphs from April correspond to reopening while at various states of risk postures: high risk, medium risk, low risk, and within each, we have re-open all, maintain school closure, maintain school closure + 25% telework. The risk posture is defined based on the amount of community spread, current infection rate, and how far the epi curve is from the plateau.

This is for a city of a million: Different line types denote different levels of strategic sample testing and accuracy. The curve measures the infection escalation with respect to the date of re-opening.

When I sent around the counties that are ready to re-open (14 days 0-nadir)), they correspond to the low-risk posture group.

Below I first plot the current escalated cases with respect to the re-opening date for 11 cities (all normalized to per 1 million). You can see many of these cities re-opened prematurely (while they are still at high-risk).

Next, I plot 10 States. We can see Arizona, Florida, Arkansas, California, Delaware, Georgia, all correspond to high-risk re-opening. DC is escalating somewhat. I hope Connecticut, Alaska, Colorado can follow the Red lines, that’s medium risk with school closure.

It remains critical to look at city/county level to determine restrict-and-relax strategies, since they reflect the local situation better than looking at the entire state. E.g., Los Angeles vs San Diego / Santa Clara. However, always keep in mind the interdependencies and cascading effects: your neighbors are equally important.

As mentioned on May 13, it is very important we perform good biosurveillance as a way to inform decision/policy makers since decisive restriction MUST BE MADE in a timely manner as we start to relax. It is relax-and-restrict (strategic restriction at the earliest sign of potential community spread). If done right, and over time, it will be longer (period of) relax, shorter (period of) restrict for every single step. We see this in S. Korea, in Singapore, in Hong Kong. Mathematically, such a sequence will converge to a very nice result of the relaxation stage with not much restriction anymore.

I want to include all the states in the reopening risk-case prediction and the actual case escalation with respect to date reopen occurs. Recall the predicted re-opening curves were done in the first week of April. That idea was to figure out when is the best time to re-open and what's the optimal daily testing capacity to ensure good containment. In the two previous plots I sent for 11 cities and 10 States, you may recall that I included accuracy in testing and sampling size. For simplicity, for these, I only include the "no testing", and "3% daily testing with 100% accuracy." That way, you know everything else is between these two lines. Again purple, navy blue, sky blue correspond to reopening at high-risk, as defined in April. I summarize some findings below.

I group the States into 3 categories

Group 1 includes the States that have the lowest escalation. Nonetheless, they do have surges (under 5,000 per million). If you look at the States closely, you will notice that Group 1 appears to achieve the "medium-risk with school closure" case numbers, yet they achieve those numbers much earlier (by 30-35 days). This shows that the re-opening is a month too early. I know it is a test of the patience of the States/people, nonetheless the longer (the disease) is dragged out, the more negative health effects it poses and the more wide-spread the disease and that requires much more perseverance. So if only they can be patient for one more month, they can have the spread under total control. It is harder now.

To figure out when to suppress (restrain), we need to look at the shapes of the curves over a period of time. An acceleration is indicated by the rate of change of the slope in the graph. I use 7 days as a time period and prepare this for each State. In the table below, the last column is the rate of change in the slope. If it is > 1, you have acceleration, if it's less than 1, then you are decreasing the positive cases. Here's how Florida looks. You can see the effect of school closure and business telework. They truly worked and helped suppress the disease spread.

Florida reopened on May 4. The cases immediately increase even though it's slowly because there's not enough testing kits to do contact-tracing and test aggressively. But once you see the acceleration, it will become rapid. (yes, death will come next.)

This again underscores that actions must be executed in a timely manner. To truly clamp down the spread, multiple levels of actions must be carried out simultaneously. We are no longer in February where school closure + 50% telework would result in 4,000-6,000 deaths. We missed that opportunity of early containment. So it takes longer and much more resources to stop further spread. We did that too in mid/late March, yes, divide-and-conquer, separating all the big networks into tiny little ones and restricting people from getting into crowds. A reopening in mid / late June would offer a low-risk safe-opening, and offers a good chance of school reopening. But we’re one-month too early in re-opening. Too late in implementing action, and too early in lifting the restraints.

At the moment the decrease in daily cases is stalled – basically the amount of test+contact-tracing is outpaced by the generation of new cases. so we must act. We need rapid testing+contact tracing, social distancing, face-masks, personal hygiene, closing of all crowd generating events and business self-protecting, travel quarantine. Our contact-trace now is quite different from S. Korea contact-trace where they are able to contain the disease. We are not back to containment yet, we need to do massive mitigation of cases to scope the spread. That is a must.

Influenza vs covid-19

Analysis of the following implies that, the average overall hospitalization rate (hospital resource burden) of covid-19 is worse than the worst of all seasonal flu combined. It highlights the disease burden and hospital resources that are required to take care of these patients. Imagine we have to deal with both seasonal flu and covid-19 simultaneously. Furthermore, the age-groups 18-49 and 50-64 are most mobile, hence vectors for transmission, and it appears their disease burden is much higher too when compared to seasonal influenza.

Yes, the disproportionate hospitalization across different race groups is very significant. I like to know when (the disease severity status) they got admitted, are they in worse conditions when admitted?

Carter: Was curious and pulled the current COVID hospitalization rates for age groups from CDC. https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covidview/index.html I then went back to the EIP data for flu hospitalizations and pulled the maximum recorded flu hospitalization rates for each age group. The 2017-18 season was the most severe overall and for ages >18; 2003-4 was most severe for ages 0-4 and 2009-10 most severe for ages 5-17. COVID hospitalizations reported by CDC (thru July 11) are added for comparison. For context, the population distribution in the US by these age groups is provided below. The age group 18-64 has COVID hospitalization rates significantly higher than recorded maximum flu hospitalization rates. This demographic is also very large (200M).

But what is really striking in terms of hospitalization rates are the differences by race and ethnicity.

Is there still hope to control?

We have talked about this "hammer-and-dance" a few months ago. I was worried at that time -- what if people don't know how to dance? Truly, the hammer was lifted too early, and the dance is random.

South Korea, Hong Kong, Singapore call it "Suppress-and-lift". We can see that even South Korea tip-toed on their re-opening and delayed when they had a local outbreak. In the same way Singapore closed up everything and allowed only 1 person to go out at any time for grocery shopping when they have to deal with the community spread. Consider Singapore (5.6 million) a city in the US. They seem to have good control now (it's been a long time since they closed up in early April), and their suppress is still on. I call it "restrict-and-relax". Can't use a hammer now, but let's make it a localized restriction tailored to the local disease and risk posture.

My email from Germany's update is just an understanding on how we can reopen next time (when we have a chance) in terms of the testing and contact-trace and social distancing, and everything combined. We can't just test and contact-trace now to contain, it cannot be, because we are way beyond containment. We have wide-scale community spread and we will need to have NPI measures. Again, some counties/cities are ready to open schools and they are fine since they have no visible community spread. But majority sites have local community spreads. They will need:

1) Cost-effective evidence-based approach to treat covid-19 patients. If they do need field hospitals, they must ensure that those hospitals will accept patients so they won't repeat the same situation as in NYC where the field hospitals only accepted patients from private hospitals, while others did not coordinate well. Either the field hospitals are used to help treat patients, or they won't be needed.

[Separate covid-19 patients, protect healthcare workers, getting personnel surge from other places or outpatient providers, and optimize clinical environment and shift hours to improve safety. Everything we have shared in great detail back in March.]

We need to know what types of treatment work best for what types of patients and when to intervene, and when to hospitalize, etc. If we can have remote patient monitoring, then we can monitor people's vitals (oxygen level, etc) so it can help hospitalization at the right time for the best intervention and treatment success.

2) Determine the most cost-effective and safe way for businesses to open or close out to maintain business continuity and economics -- bars, theatres, malls, nail salons, gyms, should all be closed for those high-risk cities/counties. Make diners into a table of 4, or close after 6pm and allow only take-out. This minimizes the number of new cases and community spread.

One of the most essential businesses to open is healthcare for all Americans. So outpatient clinics and elective surgeries, there're reasons they need to reopen because some patients simply need all those medical care. We need to provide a very safe environment for them to operate.

Essential workers and factory workers: we must protect them with PPE and we must stagger work hours and minimize infection in their working environment. All issues must be taken care of.

Private sectors, same thing, they can open if they have good means on disease control and prevention. Clearly environment, personnel, timeline, and safety steps must all be optimized to get the safest operations.

There are many screening tools to self-check, as Art has pointed out Emory has one.

Leaders can look at the business lists w.r.t. tradeoffs, GDPs, and risk factors and determine which ones should re-open and which ones can be shut down temporarily to blunt the local community transmission.

Bars and nightclubs seem very popular, even for students, there're happy hours. I don't drink nor smoke, so sorry if I feel that it is so important to close them. But how can people practice social-distance when they are drunk? I did a little econ-tradeoff analysis on alcohol consumption, it actually has a 2-7% GDP burden (negative consequence).

3) Early detention/monitoring, and test, isolate, and contact-trace.

I think every business can do waste-water/sewage testing as a means to monitor their environment. It is cheap and easy to do, and it should give us results even for asymptomatic transmission. I have suggested every business do that -- this is another MUST do.

I actually did a study on how mass dispensing of cipro and doxycycline (after responding to anthrax events) would affect our waste water, the level of antibiotics in it and how it goes to the main streams and gets back to the food chain. So tracking water is a very good idea.

We will need to test regardless if we can contain or not. Testing is the cornerstone for pandemic response, so we better optimize the process. If isolation beds/low acuity beds are needed for those positive patients, get them.

I know I am 200 years-old and a broken record because I keep asking about testing. But we can't avoid it and we can't push it aside. We must confront it head-on and continue to fix the testing and delay along the entire process. They are not the only means, but they are one of the means as part of the holistic system approach to combat covid-19 or any pandemic.

Pooling is good, and optimal pool size is important since it offers efficiency and accuracy. But truly, I fear that even with pooling, we are still running out of time and testing kits.

4) Safe space and safe actions: Individual actions regarding wearing face-mask, practicing social distancing, avoiding crowns, working in staggered shifts, disinfect and all, those we need every citizen to take part in and contribute. It is everyone's responsibility. Their incentive -- the more people buy-in and practice social distancing and wearing masks, the more business we can open and the faster we can get back to :"normal".

School re-open is a local issue, because every local has its own (covid-19) risk posture, so it is clearly not one-size-fit-all.

Take Harvard as an example, it is going to conduct all classes online. Freshman will live in dormitories. They will live in their own single cell or multiple people in a cell, and they take-out and dine together in that same quarter, and they all do things with the same group and they will sign a contract to agree that they will not venture out of all the requirements. This can work for some students, but not for others who will feel very restrictive. There are a lot of restrictions. Among students who are depressed in university (about 52% across US), 8% of them are freshmen due to adjusting to a new life, new school, new friends, etc. So we don't know how it will work for these new students. They can be happy or they may have other issues, all these waiting for us to discover.

There're workers who will serve them (physically working on campus), and so the layers of protections go far beyond lectures. We also need to keep in mind many workers are under-served minorities so their health risk is higher. It's a ton of things students do on campus, off campus, and all those have to be considered as a system to make it work.

This is what we have talked about for school re-opening: a) we test the waste water to monitor the school environment, b) we test by sampling to see how the people's risk factors are to establish the disease prevalence in the school setting, and c) we have 1/2 students take 3 days of classes, and ioff the rest and the next week, and another group take 3 days next week and off (alternating week). The wait is good for two purposes: the test takes so long to get results, so we may as well test and just send them home, like quarantine, and of course the time will be 14 days - 3, and so 11 days, maybe that will be sufficient for an asymptomatic individual to cool off. Ok, these 3 steps, plus many other steps and measures.

Now you go to nursing homes. Current nursing homes run as large-scale manufacturing systems. The process is streamlined to take advantage of economies of scale. E.g., You streamline so that a group of workers are dedicated to provide baths, and other groups are dedicated to cleaning the rooms, etc. By doing so, every resident is exposed to a list of workers that serve a large number of residents. Hence, easy transmission across the site, because nursing homes are like community living. Now, add PPE on all workers ,ok, we can reduce that cross containment. Better yet, make it into dedicated service -- assign a set of workers to take care of a small set of residents. Break them into groups, now, the residents no longer are exposed to so many workers, but just the few dedicated ones who take care of more tasks for a smaller set of clients.

It may not be the best way for mass production (service), but it can reduce as much as 54% interaction. And that directly reduces intra-facility infection.

By doing so, workers may not need to do the same tasks across multiple sites, and thus reduce inter-facility infection also.

Basically you reduce the circle of interactions to a traceable and manageable size. Now this is kind of like those cozy small family practice businesses. In the old days, that is how it's run. And people do enjoy those types of interactions. Large-scale is created to streamline for bigger profit and more efficiency. In both cases, regulations have to be placed. It is harder to inspect 150 small businesses of nursing homes, instead of 40 large-scale ones. However, if we separate the large-scale ones now into separate wings, then we can get back the small framework that is needed for the best disease control.

I run a model to analyze this and it doesn't deplete the efficiency while at the same time improving the quality and reducing the infection probability (54%-69%).

Prisons close quarters with so little space.. and they are going to spread, can't avoid it. Look, even if they don't have high mortality, they will in turn infect the wardens and someone old,naturally. But the mortality can be high because of the demographics.

I have no doubt transmission in China was spread within Wuhan and out of Wuhan (to other parts of China) by some younger asymptomatic patients. That's January. We (In US) catch some through testing, and we miss some and they interact (just like Seattle patient 0) and somehow infects someone who works in LTC, and then the aged population is infected rapidly again.

Germany's major community spread is nursing homes and slaughter farms, Hong Kong has now it's community spread and first nursing home infection.

The population is aging, and many live in communities with services. As such, the disease is brought to them.

An early widespread: Confirming my analysis and assumption that covid-19 was here in January

High Schools: Anecdotally, a high school girl, may be one of the Links. There were a couple of new Chinese exchange students in her school in early January, and seeing that they were socially isolated, she befriended them. By the end of the month the entire high school was in the grip of what was then called flu. At one point, only 1000 of the 3000+ school community were actually in attendance. That is Wachusetts Regional High School in Holden, Massachusetts, if you want to do some preliminary research. She says no-one died from the infection. Her own progress closely matched the “hypoxic injury/tissue damage/proceeding rot respiratory infection" model: first symptoms were shortness of breath, followed by fever and flu-like symptoms. She recovered in about 3.5 weeks, she said; others took longer. I suspect we have a clear, undocumented case of a significant Covid eruptiion at least six weeks before its presence in the US was officially acknowledged.

I modeled Patient 0 in New York City starting early January. So, all these timelines seem to be very accurate. We might even have some in late December, since people were traveling back to the States for winter break. It's just a perfect travel time!

These students were made aware that they're exposed to covid-19 when they're tested positive on the serologic tests.

This also gives us an idea what to expect when schools re-open. Clearly we can't afford to have so many kids get sick, so every countermeasures must be established to protect them, and that in turns, protect everyone they come in contact with.

August 2020

What strains do you target if you have a year with very low flu prevalence?

WHO often selects virus strains with small variation from year to year and learns slowly and recovers once coverage(efficacy) dips very low. It seems that the human experts are not inclined to select different virus strains from year-to-year. I cannot tell how they select, but perhaps they use some sort of algorithms of their own. I am attaching the paper on Antigenicity prediction and vaccine recommendation of human influenza virus A (H3N2) using convolutional neural networks. You can see using a system-approach, the influenza strains selected via our artificial intelligence / machine learning model can differ quite drastically from year to year and exhibit consistently good coverage. That’s because the algorithms use global information, and not just the last few years’ information. It is also we include combinatorial point-mutation, hence the influence is non-linear and in inter-connected sense. To the best of my knowledge, ours is the best system and state-of-the-art currently existing and the first to use AI and also the first to analyze and evaluate the combinatorial effect of point mutations of Influenza A virus. The results show only up to 2011 because CDC/WHO did not provide us with the data to use (if you have them, would be grateful if you would contact me!). The computational platform is very powerful and the learning ability is rapid. It is generalizable beyond flu, can be used to learn other recurring infectious diseases also. Furthermore, I can analyze all types of mutations – creating synthetic ones. I briefed you (Duane) about this a year or two ago on the synthetic ones. Not publishing those for security reason.

Interaction between influenza and COVID-19

1. Flu vaccine vs competition among viruses

Since the young and the aged are the high-risk groups for influenza, along with healthcare workers and those with underlying health conditions, there is clearly an overlap with the covid-19 high risk groups. There is a real concern how these viruses may interact – either weaken one another or strengthen to do even more harm. Either way, social distancing and face masks and personal hygiene and disinfecting environments should have the dual purpose of reducing infection even for flu. People who always take flu shots probably will continue, and those who don’t, I can’t tell if covid-19 would drive them to take flu shots.

I wonder how the two vaccines may interact and the consequences on effectiveness and health.

2. Vaccine prioritization

Some of you asked me about the various parameters used on the vaccine prioritization analysis. There are so many combinations to show. Those two I sent involve the following: a) I assume it’s 2 doses per individual, b) efficacy is 95%, c) dispensing is based on personalized prediction through vaccine immunogenicity study (hence high efficacy). In such an approach, we will get the DNA of an individual and determine in real-time if the vaccine is beneficial to them or not. d) Anyone who has positive molecular tests will not receive the vaccine, e) since it takes so long to receive immunity, I assume regular strategic testing and isolation and quarantine continues during those periods when vaccines are dispensed. f) some eagle-eyes among you notice that for the analysis with 1% active infection, “yes” herd immunity is achieved at around 64% -- with 30% vaccinated population and optimal attack rate about 34.2%. Thus, even when vaccine inventory increases, there is no difference in the overall attack rates.

There are so many issues related to vaccines, I am working along a long list of items (thanks to Jim L. I got a very nice list) and I will continue the analysis.

3. Resurgence and importance of the testing and contact-tracing

Some of you asked me about the case resurgence graphs against re-opening risk posture. Those graphs were modeled and optimized where testing and contact-tracing is performed effectively and efficiently, with testing accuracy of 50%, 80%, and 100%, and testing sampling size of 1-3%. Testing and contact-tracing remains very critical. Carter summarizes the findings reported by NPR. On the ground, I have discussed with a dozen sites these two weeks. It is so chaotic, it is either there’re not enough contact-tracers, when there’s enough, over 50% of those contacted won’t respond, or if response, and those reached refused to come in for tests, or contact-tracer never contacts those tested at all for tracing. And no one is isolating. Clearly we can’t make people isolate and quarantine for 14 days without tests or results. The breakdown is systematic. Understand that CDC is not designed to contact-trace in a pandemic situation, now it is August, we (local/state) got to finally mastered it. S Korea shows the importance of strategic comprehensive rapid contact-tracing. One can think of vaccines being an invasive intervention, then test and contact-trace is cheap and non-invasive and it can work quite beautifully. But it must be done in a timely manner and a systematic manner. Treatment and hospitalizations are intervention too, but they are later stage and so much more resource intensive with potential serious health consequences.

Public health preparedness relies on early strike, so we can contain. Now, it is not possible to contain, it is only to mitigate, but it remains crucial. If we can’t test, trace, and isolate and quarantine, the fire will sustain so much longer with many more infected people. For some reason, people think we count mortality only (item 5 – how to measure severity). What good does it do us if lots of people get sick and require hospitalization and end up requiring long-time health support because of chronic conditions from covid-19? It is a non-sustainable system. Hence, we must act, and we remain need to act, even though the whole mission now is different from February, March, … and all these months. But the goal remains the same – protect the population's health and to halt the pandemic. We lost all that time, and we can’t afford to lose more.

4. School reopening and steps to take to suppress re-surgency

Israel shows how schools re-opening can help fuel wide-spread resurgence.Across the globe, many places look similar.

Israel - infection related to school re-opening

Israel - infection related to school re-opening: Hot-spot only vs the entire state. The curves show that Israel opened school 40 days too early.

Europe is also experiencing resurgence due to re-opening.

Germany has setup a very comprehensive and effective contact-tracers, as I summarized to this group a month ago. At the start of this pandemic, unlike the United States or UK, both of which allowed their public health agencies to keep tight control over standards for tests and discouraged private clinics, labs or companies from developing their own, Germany disseminated a blueprint for a test as soon as it had one – in mid January. They quickly made it available to the country’s public hospitals and research laboratories, as well as a nationwide network of about 200 privately owned labs. Everyone focused on making test kits. This is similar to the National Laboratory Consortium that I have proposed for us to have for early detection and biosurveillance.

Whether we like it or not, universities must step up in testing as schools re-open. We must have surveillance in place to pre-empt any potential disease outbreak and smother it. Israel has given us a very loud warning and we MUST NOT repeat their mistakes as they have advised us.

We must test the sewage daily for traces of covid-19, we must test strategically (via sampling at least 3% per day), and we must spread out class meetings. Factoring into the delay in everything in the testing process, it is most beneficials to split the students into 2 groups. First group has lectures on Day 1,2,3, and off Day 4-14, and the second group has lecure on Day 8,9,10, and off for 11 days. I know I have repeated this maybe 4 times already to this group like a broken record. In the model that I have analyzed, this allows some cool-off period. If indeed there is infection, you break the cycle immediately. If they can make it meeting for 2 days per two weeks, that’s even better.

Remember small and very spread out is good, and absolutely off period to cool-off is good. You can imagine the scenario – Day 1 class meeting and tests, and Day 2 results back and confirms 4 infections. So it already involves many students/staff being exposed. So cooling off is ok because you cut off the spread immediately.

Screening symptoms itself really doesn’t do the same thing as in testing, so sample testing is a must. By testing, it means test and contact-trace.

There are of course many other things we have to do for schools, the list is long, and it will get longer.

5. How to measure the severity of the disease, and covid-19 chronic conditions

Singapore shows it took 4 months to stop a very tiny local community outbreak (domestic workers, mass dwellings) that ultimately resulted in over 0.8% of the country population. Hong Kong shows how vulnerable TLC is even when the infection is so extraordinarily low, yet, one service worker can infect across multiple sites – exactly the same as Seattle’s first case. This shows that the spread is so effective through highly mobile individuals and that it takes a lot of effort to mitigate, even for what seems to be a tiny little fire and yes, testing and contact-tracing is so crazily important and time is so critical and so essential. Community living and working environment – as in TLC, prisons, factories, etc, fuel the spread and increase the mortality. You will expect the majority of the people in these communities to be infected once it starts. And hence TLC remains at very high risks because of their intrinsic high mortality rates. However, we must not only measure death as severity.

Many of you have now seen long-hauler covid-19 patients. Before they’re in the news, I have already collected a few dozens of them. Many are healthcare workers. Many were tested negative repeatedly, yet they have many symptoms of covid-19. More importantly, they have not healed even now (that’s since March)!!! This is really serious. “Slow burn” as I label it, has a large number of people getting infected, not too sick to die rapidly. Yet, some remain hospitalized for a long time, and ultimately, may sustain some form of disability – permanent damage to the lung, heart, kidney, or neurological functioning. Those who are not that sick, odd, they never really made it to the hospital stage, yet they suffer uniformly long sustained symptoms that are debilitating. Ultimately, covid-19 may be declared a chronic condition, or it should be declared now, since there are so many healthy yet long-haulers who clearly are not getting back to their normal self health-wise. This truly frightens me, because these were our very healthy population!

Our health burden, even without covid-19 is already so high and so expensive. This situation worries me a great deal and hence I proposed in late April on re-opening strategies about re-thinking, adapting and advancing the healthcare systems so that we can be very effective in handling covid-19 and regular patients. One may think of this as short-term just for now with an active infection stage. I fear the disease burden is much more long-term and hence it will truly require a different smarter way to deliver healthcare.

So we have the younger kids carry 10-100 times viral load, the older kids are the best disease carriers, the adults (not old ones) stay in hospital long and suffer permanent lung/heart damaged, but they don’t perish, and the aged and those with co-existing conditions, they are at high risk of mortality. And the minorities carry the blunt blow due to health disparity and poor health with co-existing conditions, hence suffer disproportionately. Is there anyone there to spare? This is the worst healthcare nightmare for us; hence we MUST preempt and we must mitigate in the best possible way we can.

Healthcare GDP is nearly 18%. Now, with the slow burn across so many cities in the US, including rural areas, the entire population is feeling the squeeze – those in need of healthcare service (not possible via tele-health) will suffer. Those need surgery will be delayed and face possible emergency surgeries which dampen the outcome. Even as simple as dental care, that cannot happen, but dental care remains vital to the basic health of individuals. This justifies every non-invasive measure – face-mask, social-distance, smaller groups, etc, because these simple actions by the mass population can bring back so much more “normalcy” and businesses, and allow our healthcare to serve the general population again and our service sectors to open safely.

6. Disease timeline

Attached is a disease timeline process from about 400+ patients that I have generated. It is ad-hoc and not comprehensive. Once I get full clinical data, I will automate it to run through all clinical processes to identify practice variance and uncover best practice.

So we are right in February: healthy asymptomatic people are carrying the disease everywhere!

Here's a "new" piece of information, which we have argued to be the case back in late January and early Feb. Now, WHO accepts it:

The coronavirus pandemic is being driven by people in their 20s, 30s, and 40s who don't know they're infected, according to WHO

I maintain, as I have mentioned many times (as a broken record), these healthy individuals are not immune from the damage/harm from the disease.

There is clear evidence of damages to lungs, heart, kidney, and neuro, and some are having chronic symptoms. This is really really serious.

I remain very concerned with some universities not following clear guidelines and not doing enough to protect..

Vaccine and Point of Dispensing (POD)

1. Vaccination - point-of-dispensing. In the vaccine prioritization, I incorporated efficient POD operations within the model. If you ever want to optimize your dispensing locations and throughput and best dynamic resource allocation for the region you are in charge of, I am happy to do it for each of your site since I do have powerful tools for mass dispensing operations, walk-through, drive-through, mobile, closed POD, open POD and those with various language operators. It also minimizes disease spread in the layout design, in addition to on-the-fly dynamic resource allocation of scarce resources (e.g. personnel, equipment) The RealOpt system was designed since 2005, with CBRN and contingency capabilities, and it’s been advanced continuously.]]

Some of you asked me if 40 PODs are sufficient for a population of 3.3 million and also the POD processes. The POD includes enter POD, greet and paperwork, medication consultation (very small percentage of people need this), vaccination, observation and followup signup, and exit. They are pretty much what the local public health have been doing in setting up the POD operations for MCM dispensing that requires medical personnel. I have done hundreds of mass dispensing time-motion studies for the last 17 years, and have many real-data to use. So I use the real-data to establish the service distribution for each of the processes. For observation (that’s to observe if there’s any rapid negative effect), I put down 15-25 minutes. During this time, we can use it for education, sign up for follow-up boost, and also health effects.

Here’s the solution for San Diego County. I am using 10 days to do the first dose and 10 days for the boost 21 days later. During this time, testing and contact-tracing continues. Some of these sites have very high Hispanic population (> 75%), so the PODs are manned by Spanish-speaking staff.

The optimal solution contains 40 open PODs operating an 8-hour shift every day. They have different hourly throughput in each site depending on the physical constructs and fire code. And each POD location includes socioeconomic data, demographics, education, age, etc, so you can prepare if there’re many children, or it should be drive-through or walk-in.

Clearly engaging local businesses to vaccinate their own people may seem a good idea to lower the public health burden, but with covid-19, we probably cannot do that due to it being so new. However, prisons, universities, healthcare workers etc, should have closed PODs with teams of public health personnel inside doing the work. I have a ton of materials here (literally 2 full bookcases filled with stuff on this), so I am happy to discuss and provide assistance.

And within each POD, there’s the optimized minimum number of workers needed to carry out the operations. This covers about 2.8 million individuals. The rest of the population is served by one of those closed PODs.

In reality, we won’t vaccinate the entire county since (a) there may not be sufficient vaccine to cover each citizen, (b) herd immunity would be achieved before 100% individuals are vaccinated, (c) some citizens simply don’t want the vaccines, and (d) there are individuals who cannot take the vaccine. Also, high-risk can include many different groups of people – essential workers as healthcare workers, nursing home staff, those who work in transits, under-served population, meat-packing/factories etc. One should try to define them the best they can within the region.

It is easy to setup a closed POD inside these organizations and carry out the vaccination. There is no reason to have people in nursing home to go to open POD, or essential factory workers to go to open POD, if we can setup closed PODs and have the team of public health personnel operate there. This allows for better monitoring of MCM effects and in education and communication of follow-up boost and collection of MCM effect.

Here’s a glimpse of the first POD with 1,335 per hour throughput. On average, people spend 26 minutes inside. You can see vaccination has a queue of 71 and it’s busy at 94% utilization rate. If you add an extra worker there, you can reduce the queue to 12 only. Keep in mind – it’s not good to do manual resource allocation because dynamic resource allocation is one of the hardest problems. So the optimal solution is optimal – the best use and distribution of resources. And human usually is functioning at 15%-40% efficiency (even within highly trained staff, it is the allocation that is the bottleneck, not the human workers themselves). But if you have one extra worker, then you like to know what is best to use him/her.

I paste part of the report here. It has more detailed information.

RealOpt 8.1, Lee et al, Georgia Tech Copyright 2003-2019

--------------------------------------------------------------

Optimization and simulation results summary

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Model: Covid-19-POD-SanDiego.mod

Simulation time: 8.0 hour

Function: minimize resource allocation

Minimum required throughput: 10680 Individuals (1335 Individuals per hour)

Last entity exit time = (8 hr 32 min 14 sec) +/- (1 min 37 sec)

Actual throughput = 10680 Individuals

Flow time = (26 min 17 sec) +/- (1 min 18 sec)

Optimal "Personnel" allocation:

Total Nurse Doctors Staff volunteers

Greet and Direct 1 0 0 0 1

Medical Consultation 1 0 1 0 0

Vaccination 31 31 0 0 0

Checkout / ID verification 11 0 0 11 0

Detail statistics for individual stations:

Greet and Direct

..Queue length = 0 +/- 0

..Waiting time = (0 sec) +/- (0 sec)

..Num of resources = 1

..Utilization = 6.3% +/- 0.0%

Medical Consultation

..Queue length = 0 +/- 0

..Waiting time = (2 min 7 sec) +/- (30 sec)

..Num of resources = 1

..Utilization = 46.8% +/- 4.6%

Vaccination

..Queue length = 71 +/- 25

..Waiting time = (3 min 25 sec) +/- (1 min 13 sec)

..Num of resources = 31

..Utilization = 94.0% +/- 0.3%

Checkout / ID verification

..Queue length = 28 +/- 8

..Waiting time = (1 min 21 sec) +/- (23 sec)

..Num of resources = 11

..Utilization = 94.7% +/- 0.2%

2. Herd Immunity

The herd immunity, no matter how I ran it (since January all the way to now), remains pretty stable – 45% - 85%. It truly is not the same across everywhere. You can see in the vaccine prioritization analysis that I have. If we are at low-risk posture with only 10 active infected cases, we could reach herd immunity at 42.52%. Whereas, at 1% active infection, it will require 65%. So the range depends on our risk posture at the time of vaccination. I hope we can maintain a good control and not escalating.

On May 17, we discussed how U.S. would fare if we acted like Sweden and I ran the model on multiple key sectors. It’s interesting how the model reflects school’s infection, some of these fit perfectly to the situation that is happening around the world now (including US). If you stare at the little kids – K12 – a high percentage of them will be infected, but only a small percentage will require hospitalization. The 3-day class and 2-week staggering, it works for K12, but it won’t work well for university students since they’ll have big gathering and won’t be able to adhere to social distancing off-class.

3. Singing and talking

https://www.bbc.com/news/health-53853961 interesting small study

I do believe depending on how people talk (the way the use their throat and voice projection), some people spit out more droplets than others. I have taken some measurements in the past, ok, you know I am obsessed with hygiene and I measure everything. I don’t think the parotid glands secretion (amount) is identical among people. You can tell some people have more saliva than others while they talk. So it’s best to protect one another by wearing a mask. I learn that many people actually do not know how to use the mask, they can’t figure out which side should face outwards, even some of the healthcare workers don’t know.

4. Something we’ve talked about back in February / March about little kids

https://www.news.harvard.edu/gazette/story/2020/08/looking-at-children-as-the-silent-spreaders-of-sars-cov-2/

Many studies have supported this now, everything we’ve worried about 6 months ago. China is an outliner since they don’t have many little kids. S Korea has very low birth rate. France has the highest among European country.

5. Everywhere in Europe: covid-19 cases are escalating

Hot and humid summer and covid-19 is spreading. Cold and dry and it’s spreading too. In any case, there’re so many means to spread that it is testing us (human) to be “perfect” in our protection. And that is not an easy test to pass.