In 1992, Marci Layton, an infectious disease fellow at Yale University, applied for an Epidemic Intelligence Service (EIS) position with the U.S. Centers for Disease Control and Prevention (CDC). “When I was trying to decide where I wanted to do my two-year fellowship, I happened to bump into the current EIS officer in New York City. He said that if I really enjoyed infectious diseases and didn’t want to specialize in just one, instead of traveling abroad—which reportedly gets old after a while—I could come to New York and work on a variety of things with the advantage of still sleeping in my own bed at night.”

Layton was dubious. “I couldn’t imagine living in New York City. It wasn’t my first choice for EIS—it was my third choice. The city intimidated me. I’m by nature quiet, and not a public person. I originally wanted to be in New England or someplace more rural.” Nevertheless, New York City is where she landed—just as a series of unprecedented infectious disease outbreaks was about to strike. In August 1994, she formally joined the department as Assistant Commissioner of Communicable Disease. Today, the EIS officer who had originally talked up New York City— Thomas Frieden, MD, MPH—is her Commissioner.

After ten years, more than a thousand outbreak investigations, a tuberculosis epidemic, the hemispheric debut of West Nile virus, the September 11 attacks, anthrax spores in the mail, the global SARS threat, a massive bioterrorism preparedness campaign, and countless other crises, Layton has more than adapted to the job. Her cool head, ferocious work ethic, and visionary approach to surveillance and communications have won her international respect.

After the 2001 terrorist attacks, Layton received numerous professional awards—honors that she insists belong to her entire department. “But the one that meant a lot to me was from the Council of State and Territorial Epidemiologists, the Pumphandle Award.” It was given, in part, for her department’s swift and fact-filled updates during the World Trade Center attacks and the city’s anthrax outbreak that were shared with other state and local health departments nationwide. “I used to say, when I got awards like that, ‘Wait a minute, you’re supposed to get these at the end of your career.’”

Only in her mid-40s, Layton acknowledges that she has already entered the annals of public health history—an area of scholarship that itself fascinates her. “My dream retirement job is getting a degree in the history of medicine and specializing in the history of public health in New York City. I give a lot of talks. If I had to talk about hypertension or diabetes management, I wouldn’t be able to give 30 talks a year—I would fall asleep while I was talking. But once I start talking about something we’ve been through here—whether it’s West Nile or anthrax or SARS—I get completely engaged. I happened to stumble into something that fits me perfectly.”

Layton spoke on November 6, 2004, with Madeline Drexler, a Boston-based journalist and author of Secret Agents: The Menace of Emerging Infections

Q: Just a month after you began your current job, plague broke out in Surat, India. Did that foreshadow the many global infection threats that you would face?

A: Yes. It was an immediate reminder that by being based in New York City, one of the largest ports of entry to the U.S., we needed to remain alert to outbreaks worldwide. Given the amount of air travel between India and New York City, it was a very real possibility that someone with plague could come here and become ill either en route or after disembarking. We needed to raise awareness about plague among medical providers in the city and think through how we would isolate and manage a suspect case. We had ten calls of suspect plague cases, and though none were confirmed, this experience laid the foundation for our future emergency response planning for other infectious disease issues, including bioterrorism. We started a broadcast fax system for blasting health alerts to all city hospitals—which has transitioned into the Health Alert Network—right before the plague outbreak in India was recognized. It was a very simple technology to start. We had a fax machine that sequentially was able to fax every infection control office, microbiology laboratory, and emergency department in the city. It was very slow—taking most of the night to reach everyone— but that was the technology at the time. It was before email. Now it’s evolved to an Internet-based network with the ability to send both fax and email alerts, similar to the Health Alert Networks that are in every other state.

Q: After that, New York City became known for its ability to quickly communicate with medical providers during an emergency.

A: My philosophy is that when a health issue is breaking, I do not want them to read about it in The New York Times or The New York Post the next day. I want them to get the detailed information that they need, and I want them to get it from us. At the same time as our press office is working on press releases, we’re working on health alerts. It’s not the last thing we do—it’s often the first thing we do.

Q: Those public press releases are something else your department is known for.

A: In New York City, we’ve learned that when breaking news happens, we go public quickly. We don’t want to keep secrets—and it’s hard to keep things quiet in a city like New York. When the inhalational anthrax case happened in 2001, we announced it around 11:30 at night, soon after the confirmation came in. We’ve had a couple of rule-out smallpox cases in recent years. We first heard about one from the hospital. As we were on our way out to investigate it, I got a call from CDC: They had just heard there was a smallpox case in New York City—from CNN.

Q: What’s the key to good risk communication?

A: It’s trusting the public and providing honest information in a clear and effective way. One of the challenges we often face in public health is communicating uncertainty in a way that is understandable. If we tell them that this is a breaking story, we don’t know yet what is going on, this is what we’re doing to find out, this is when we’re going to get back to you—the public can accept that—as opposed to saying, “Oh, don’t worry about it, it will be OK.” Because it may not be OK a couple hours later. Once you have miscommunication and lose the public’s trust and the media’s trust, it’s really hard to regain.

Q: New York has had more than its share of public health emergencies in the past decade. What were the lessons learned after each—starting, say, with West Nile virus?

A: With West Nile, we began to think about emergency response. We recognized that when a citywide emergency happens, we need to mobilize the full resources of this department. We formalized our incident management system as a direct result of West Nile. With the delayed recognition that West Nile virus was the cause, partly due to the delays in recognizing the connection between the human outbreak and a simultaneous epizootic among birds in the city, we made animal diseases officially reportable to us. At the time, with the exception of rabies, there was no animal disease surveillance that we were directly responsible for. We didn’t just change the law—we built relationships and hired a public health veterinarian whose primary role is outreach to the veterinary and wildlife community, not just the clinical veterinarians in the city. So, if they saw something unusual they’d call us. We built a mosquito surveillance and control program—we had none prior to the ’99 outbreak. It’s become a model mosquito arboviral surveillance and control program.

Q: What did you learn after the 9/11 attacks?

A: The World Trade Center attack was—it’s beyond words. The department was activated 24 hours a day. We were doing 12-hour shifts each for the initial weeks after the response, dealing with a multitude of issues, including improving our surveillance for bioterrorism. It was an unprecedented emergency. The incident management system helped. The people who were assigned to the section that I’m the chief of—the surveillance and epi section—knew that they would be needed within minutes of the second plane hitting the towers, and they knew where to come. We had thought through the initial surveillance and epidemiologic response to any public health emergency and had developed a generic checklist. At the time, it seemed simplistic to do, but I can’t tell you how useful it was on 9/11. Looking out the window, seeing the buildings on fire, realizing the tragedy that was about to unfold, it helped to have something to guide our initial response.

Q: What about SARS? What would New York City have done if it had seen the same number of cases as Toronto?

A: It’s a fair question. Of all the major emergencies that we’ve gone through, we never went through anything like the SARS outbreaks in Toronto and other cities. We’ve not had a large contagious disease outbreak to test our emergency response plans. I’m very glad about that. With SARS, we did have a couple of close calls. The physician from Singapore who had been in New York City for an infectious disease conference, and who was recognized as having SARS after leaving the city and during a layover in Germany, easily could have been admitted to a New York City hospital. The woman who ended up being the index case in Toronto transited through the New York City area, and, since she became ill on the flight, she could have been taken off the plane and hospitalized locally. And the original index case in Vietnam was a New York City resident who could have decided to come home for his care; he was too sick to travel, however, and caused a large nosocomial outbreak in Vietnam. SARS, more than anything else, made us think through our plans for contact tracing, isolation, and quarantine. We triaged about 300 calls concerning potential SARS cases. There were only 20 or so that met the clinical case definition—none of them tested positive; it was a pretty broad case definition. But they all had close contacts. So we did experience the challenges in identifying and monitoring contacts for a 10-day period. It was a tremendous effort. We had two suspect cases who needed to be detained legally, because they were not able or willing to isolate themselves in a private residence once they were discharged from a hospital.

Q: New York had a close call. Still, what if the infection had silently broken out, as it did elsewhere? How would your department have handled it?

A: The index outbreak would have been difficult for any jurisdiction to have quickly prevented, because it happened so quickly and it was a newly recognized virus. The one thing that I walked away with, having observed the outbreak mostly from afar, was that SARS was relatively easily managed. The challenge was recognizing a suspect patient quickly so that the person could be immediately placed into isolation. Even countries that didn’t have the capacity to utilize airborne precautions were able to stop the outbreak, just by isolating patients and identifying and monitoring contacts, and isolating them if they became ill. With something like SARS, where there was no treatment and no vaccination, the only measures you have are strict adherence to infection control and quarantine precautions. Once patients were discharged home, we mainly monitored them by phone. But when there was a concerning case, there were people who actually went and spot-checked patients at home to make sure they were being compliant with isolation precautions. Especially in these days of cell phones, you never know where somebody is.

Q: How would your department respond to a smallpox case?

A: One confirmed case of smallpox would be considered a bioterrorist outbreak, with the expectation that more cases were likely. If the outbreak were small enough, then our priority would be contact tracing and ring vaccination, because that’s how we’re going to control the outbreak. We would also begin mass vaccination— because once we have confirmed a smallpox outbreak, we know that somebody has the virus who shouldn’t, and we’d need to vaccinate, given the concerns of future attacks. If we had hundreds or thousands of cases, contact tracing would be very labor intensive, and it makes more sense to put all our effort into mass vaccination.

Q: What is the biggest challenge in conceptualizing such a mass vaccination campaign?

A: From a medical perspective, it’s realizing you can’t do business as usual. You can’t have a nurse or clinician at every step. Physicians and nurses tend to ask a lot of questions, and during a mass vaccine clinic, we need to use a triage protocol that optimizes our ability to move people through quickly; only people who have medical issues, such as underlying diseases, would be pulled offline to be seen by a medical provider. We will also need to address the public’s concern and expectations for immediate access to vaccine. There’s only going to be a small percentage of the public who will need the vaccine immediately, either because they were involved in the initial attack or exposed to a known case. We may not need to do everyone on Day One—but everyone is going to want it on Day One. Another issue is the tremendous need for staff to conduct these clinics citywide. Will staff come in to work at these clinics during a terrorist attack? We conduct drills every once in a while, so that our own staff and our volunteer corps understand their roles and buy into the fact that they would be needed and are comfortable with what they’d be doing.

Q: How would you handle public panic?

A: Preparing a community to be resilient to the mental health impact of terrorism is a challenge. In addition to pre-identifying and training the mental health resources that would need to be mobilized after an attack, there is a need to better educate the public regarding what steps to take after an attack to protect themselves. Israel has probably done a better job than any place in the United States. Many people in Israel know where they need to go for vaccine or antibiotics after a bioterrorism attack. In our emergency management materials to the public, this concept has been mentioned generally, but not in the detail that may be required for the public to know, “OK, this is where I go in my neighborhood.” There are positives and negatives about publicizing this level of detail in our response plans. Some people believe that there are things you should keep behind the scenes—because if the terrorists knew, they could interfere with your response. But I’ve been impressed when I’ve met people from Israel. Many know what to expect from the government when something happens, and they know what they’re supposed to do.

Q: Would mass vaccination be more difficult in New York today than it was during the smallpox outbreak of 1947?

A: I’ve done a lot of reading about the 1947 smallpox outbreak in New York City; I have a historical talk on the outbreak and how it unfolded from the perspective of my predecessors here at the department. It was a very different time. First, it wasn’t a terrorist attack, so it didn’t have that flavor on top of the outbreak itself. Second, it was actually a small outbreak, with only 12 cases in the third wave of the outbreak. In retrospect, mass vaccination probably wasn’t even needed; contact tracing and ring vaccination would have controlled the outbreak. But at the time the decision was made to vaccinate the whole city, the epidemiology of the outbreak was not yet clear. Third, it also occurred right after the war, at a time when there was trust in government and a sense of civic duty. There was the Civilian Defense Board and other community groups that were geared up for community service and could be leveraged.

Q: How is New York carrying out flu vaccination this year?

A: The primary goal is that we want to direct the vaccine to those who need it most, based on targeting those at highest risk for hospitalization or death due to influenza. We normally provide very little influenza vaccine to the city—most of it is given out by private providers or clinics. But because many private providers don’t have vaccine, our public health clinics are very busy in certain parts of the city. Our small immunization clinics weren’t meant to have hundreds of people waiting outside. To avoid that, we put in place our point of distribution (PODs) mass vaccination plan. They’re not full PODs; it’s not like what would happen during smallpox, where we would be attempting to provide vaccine for everyone. But we are using that model to move people through our clinics efficiently. We looked at the Disney model of moving people through lines.

Q: One of America’s unsolved public health mysteries is: Who mailed the anthrax letters in 2001? That October 31, a 61-year-old New York City woman died of inhalational anthrax. Did you ever pinpoint how she became infected?

A: I never felt more like a medical detective than when we investigated that case. I took the initial phone report from a very good infectious disease doctor in the city. I suspect that many other physicians may not have thought of anthrax that quickly—in a patient who wasn’t in an obvious risk group given what was known about the outbreak up to that point: that is, being someone associated with a high-profile media site or government office. This was a woman who worked in a stock room in a very small hospital in New York City. The physician suspected anthrax based on her clinical presentation, even before the Gram stain came back. In that sense, it was even more impressive than Florida, where they suspected anthrax only after they saw Gram-positive rods in the spinal fluid. This case didn’t fit the epidemiology of other cases associated with this outbreak. So the question was: Did she have the same mode of exposure as the other known cases at that point of the investigation—contaminated mail—or was this the beginning of a new outbreak? We also needed to ask: Was she the terrorist? Did she know the terrorist? Or did she accidentally walk by where the terrorists were working? And that is one of our lessons learned: that you can’t necessarily predict risk exposures based on the current epidemiology of an intentional outbreak. The terrorists could change the mode or site of exposure. We can’t predict what the next attack will be. During this investigation, we needed to determine everywhere this woman had been in the four or more weeks prior to her onset of illness. What was really challenging was that—hers was not an atypical story for New York—she was an older woman who lived by herself, had very few friends and no family in the area. We knew when she was at work, but we could only account for a small percentage of her time outside of work. We very quickly ruled out the worksite as the place of exposure based on active case-finding and environmental testing. As we were ruling out the worksite, we also were trying to find her friends and family, interview people in her neighborhood. We went with pictures of her. We knew she spent time at church, though not just one church, as she seemed to have lots of information about many different churches in her apartment. We knew where she shopped, based on receipts that we found. So we tried to reconstruct her life, in order to focus our surveillance and environmental testing efforts, but we still could not account for most of her time. We are very confident that the exposure wasn’t in her home or work. We also tested the subways. Although we knew by that point that there hadn’t been a major release in the subway, it was possible there was a small release in the subway that was botched, and only one person got infected. And we recognized the importance of knowing if someone had tried this, especially to help focus the criminal investigation. We were able to test every station she went in, based on her subway card usage. All tests were negative. We didn’t find one spore—which was good. But we needed to think through how we would respond if we did. We actually didn’t start testing until we had a plan in place for how we would handle a positive finding, including risk communication to the public and media. At the end of our extensive investigation, we still did not know how she was exposed. She remains, by herself, an unsolved mystery. But then the Connecticut case happened, which led to this theory of cross-contaminated mail. Connecticut actually had an easier task than we did, as their patient’s family knew everywhere the patient had been, to help guide their testing. And they still couldn’t find a spore, except in the mail distribution center into the area. We knew we also had spores in our distribution center to the hospital and into the city. So in the end, I think that she was exposed to a letter that had been cross contaminated after passing through one of the affected postal distribution centers, but we’ll never know for sure.

Q: If you could sit down with President Bush and make three requests for the public health system, what would you ask for?

A: [Pauses.] It’s as if I’ve been given three wishes, and I want to use them effectively. First, there is a need to distribute funds based on risk. In public health, we always use risk-based strategies to target our prevention efforts, and we should do so when it comes to terrorism preparedness. In New York City, we always point out that we were the victims of two of the four planes that struck on September 11, and we received four of the seven known anthrax letters, but we receive a disproportionately small percentage of the federal preparedness dollars. Second, I’ve always been concerned about the sustainability of the federal bioterrorism funding. Most of what we do in public health isn’t done by equipment or supplies that we can buy once, with the costs declining year to year. Public health is a personnel-intensive profession. It requires being able to recruit and retain qualified, motivated staff. We are lucky in New York City that way. We have used our grant funding mostly to hire staff. A lot of health departments didn’t make that decision, because they were worried about the sustainability of this funding. The last thing you want to do is hire a lot of people for two to three years, build up a program, and then suddenly lose the funding so that all the efforts fall apart. We decided to take that risk, given the priority that emergency preparedness is in New York City. Third, we need to recognize that not all jurisdictions are the same and that preparedness plans are not “one size fits all.” Each jurisdiction needs to determine how best to do things locally. Some federal grant programs have restrictions that don’t allow for local capacities and priorities. One example is the City Readiness Initiative. It’s new money that is less flexible with respect to how we can use it. This program to plan for prophylaxing the city in a short period of time has come with a lot of oversight and expectations. We’ve done so much work here on this issue already. We’d like to be allowed to say, “These are our needs; we want to use the money for this.” Lastly (my extra wish), I also worry about our federal public health resources, especially the CDC, and hope that the necessary investments to maintain and enhance their capacities are sustained. The CDC has such a long and illustrious history in public health. What makes CDC such a valuable resource to local public health officials like me are the disease-specific experts they’ve been able to develop and nurture. No health department in the country is going to be able to maintain expertise in all these different diseases—we’re generalists. When anthrax happens, I don’t have time to pull out 20 journal articles and figure it out myself. I want to be able to call their expert or have access to their reference laboratory expertise. And the lab expertise at CDC is the best, bar none—the histopathologist there who helped us with West Nile and anthrax is one of my heroes, Dr. Sharif Zaki. They have some wonderful disease experts, like Keiji Fukuda for influenza.

Q: New York has invested heavily in syndromic surveillance. What do you see as its pros and cons?

A: We think it has value. Its ultimate worth—being able to identify an outbreak earlier than anything else, resulting in the ability to mobilize a response that significantly reduces morbidity and mortality—has yet to be proven. It may or may not be possible. And there are opportunity costs—depending on what threshold you use in your statistical analyses, you can generate a lot of signals that require investigation and use a lot of staff resources— resources that could be used for other things that are just as important. It’s not for everywhere. I came here from Alaska. If I lived in Anchorage, where there are only a few infectious disease physicians, I would likely invest my time in building strong relationships with every ID doc in town. I’m a firm believer in traditional surveillance, but I’m not naïve enough to think that every doctor in New York City knows to call us, cares to call us, wants to call us. There are definitely examples where they haven’t. So syndromic surveillance gives me at least a sense of what’s going on in the city. The inhalational anthrax case was called in on a Sunday night around 10 o’clock. The next day, we had an alarm in our emergency department syndromic surveillance system around the Upper East Side, where the hospital she worked at was located. We investigated that signal extremely aggressively, because we were worried that it was the beginning of a third terrorist attack—an aerosolized release of anthrax. Obviously, it wasn’t—and our signal investigation did not identify any other concerning cases. The signal didn’t continue, and every day that syndromic stayed quiet, I felt better that we weren’t missing an inhalational anthrax outbreak. The same during SARS: It was very quiet during SARS. I was worried that given the large amount of travel back and forth between here and Asia, we might be missing something. So with several syndromic systems in place by 2003 (emergency department visits, ambulance calls, pharmacy sales, and worker absenteeism), having an ability to keep your finger on the pulse of the city, even indirectly, is something I value. We’ve shown over the years that syndromic surveillance is really good for detecting citywide viral activity, whether it’s flu or norovirus. What it hasn’t been as useful for is detecting small outbreaks earlier than through traditional means. The one outbreak we detected that we would not have known about otherwise was a GI outbreak that occurred after the 2003 blackout, most likely caused by people eating food that was spoiled. The only evidence we had of this outbreak was through syndromic surveillance. No one called us. There’s an interest now at the federal level in investing in national syndromic surveillance systems. For jurisdictions that don’t have anything, there is some value in having it done for you. But I’m concerned about a perception— not necessarily at the federal public health level, but at the political level—that syndromic surveillance is better than traditional surveillance, that you don’t want to depend on public health to detect outbreaks, so let’s set up systems to do it for them. But syndromic surveillance systems are just smoke detectors—unless you have a public health infrastructure to investigate, it is impossible to determine if an actual outbreak is occurring and what the cause and routes of exposure are. We look at our data seven days a week. If we see anything, we have staff on call to investigate. It requires that commitment. If you don’t, it’s like placing smoke detectors all over the city but not investing in the fire departments needed to respond when they go off.

Q: Do you ever talk with old timers in public health and compare your job to theirs?

A: There are a lot of ways it’s changed. For the most part, public health has benefited from all these recent emergencies—we’re more visible. In New York, we’ve used these emergencies to promote the importance of reporting. The benefit of this is that people call us. But the disadvantage is that people call us—we’re busy. It’s amazing to me how busy we are compared to the way we used to be, even though we have five times the staff compared to when I first started. I average 200 emails a day. We have several new outbreaks each week. Taking an hour for lunch is a rare event. We are like the fire department within the NYC Department of Health. You have five things that are urgent to do. You walk in your office, and two new outbreaks happen. You have to put those five urgent things aside and deal with the acute outbreaks.

Q: What keeps you in this job?

A: I’ve accepted and take seriously the emergency preparedness aspects. But what I love about this job is the opportunity to work on and continue to learn about infectious disease epidemiology. New issues come up every week. Every week we do an outbreak review with the entire staff. I’ve got a very bright, opinionated staff, and we often disagree with each other. And these disagreements often lead to our developing better responses or plans than if we worked alone. Sometimes new people walk into one of our staff meetings, and they think we’re not getting along—but we actually get along wonderfully. That meeting is my favorite meeting of the entire week. I run it like resident rounds, where we go over the outbreaks and I ask folks questions. It’s just a fun time. Whenever I walk out of that meeting, I think: This is why I’m still here.