Infection rate used here is the daily infections (averaged over the previous 7 days to account for delayed reporting systems) divided by the number of millions of persons in a given population. Without social distancing and other mitigation efforts, the plots above would appear as a straight line crossing from bottom left to top right of the chart. States with successful prevention policies or social behaviors will have lines that plot lower and leftward in the chart compared to others. Washington appears to be the state having the most success deterring the spread of infection (by more than an order of magnitude!). South Korea followed by Germany in a distant second are the best examples of successful reduction in viral spread.
Note: Recoveries are factored into data for US, NY and DC. Other states tracked here do not report this regularly.
The WA plot is likely far closer to the real behavior of the virus in a population than all other plots. First thing to note is how different Washington's data is from the others. It starts much earlier than all other US data and shows a smoother arc. Washington, at times, displayed more cases than all of the US (which is of course impossible). The main reason for this is that, once broader testing began across the US in March, they reviewed past cases and back dated cases to their date of first symptom if able.
Identification of community spread infection was egregiously delayed. The early red flags of non-originating cases were not immediately followed up with wider community testing. For example, the first case in MA was actually Feb 2nd but it originated in China as the man traveled from there to MA. This non-originating case is not counted in the MA data above and any community testing to determine spread of contagion did not begin in earnest for over a month. Data illuminated by WA's back testing of nasal swabs show us that the virus was certainly in the MA population throughout February and perhaps earlier than that.
Date of public knowledge for first non-originating cases vs. originating (community spread) cases:
non-orig orig
US 1/16 (WA) 2/26 (CA)
CA 1/25 2/26
WA 1/16 2/28
MA 2/2 3/2
Measures taken in S. Korea were extremely effective. The S. Korea line bends much more sharply than the others and was the first to plateau.
Case-fatality risk (CFR) is normally use to describe the severity of a disease. Since covid-19 the true prevalence of the virus in populations is still unknown, I have created a new metric that will allow us to compare the diseases more readily. Once better testing is completed we can revert to better CFR comparisons.
Risks calculated below are total deaths (or hospitalized) over total number of people who sought a medical visit. The medical visit number may be a better number to compare to covid (rather than total symptomatic) at this time because most tests are being performed on patients seeking medical intervention.
The 1918 pandemic flu (pejoratively known as "Spanish" flu) is estimated to have killed somewhere between 1% and 7% of all humans at the time. Covid data used above is from Massachusetts cases (as of May 8, 2020). Other flu data used above describes the whole US population.
Data on 1918 flu comes from Wikipedia which references US Public Health Service house-to-house surveys. 2017 flu data comes from CDC and Covid data comes from MA's mass.gov.