This past April, an unusual syndrome began to emerge among a small group of children in Europe. Previously healthy patients, ranging in age from four to 14, came down with stubborn fevers, aches, vomiting, and other serious symptoms that required hospitalization. Experts linked the illness to the novel coronavirus, another unexpected and puzzling twist in a pandemic where most of the focus has been on the devastating effects in adults.

The hyperinflammatory response to the virus in some children is just one of many mysteries Leora Feldstein ’08 is attempting to unravel as an epidemiologist at the Centers for Disease Control and Prevention (CDC) in Atlanta, Ga. Previously focused on influenza, she is now working marathon hours as part of the CDC’s pandemic response, collecting data about patients and trying to decipher what it can tell us about this outbreak.

Recently, she and colleagues published a study describing the coronavirus-related inflammatory syndrome in children in the United States. The illness is rare, but it can be serious and life-threatening. Feldstein is working on a follow-up study to explore why some children develop such a severe reaction to the virus while others have mild symptoms or none at all.

“We’re learning as fast as we possibly can,” Feldstein said, adding that the agency’s other outbreak responses tend to involve diseases that have been around a long time, with established experts to consult. “This is just completely unprecedented.”

Still, her previous work on influenza, which focuses mainly on vaccine effectiveness, has helped streamline parts of the CDC’s pandemic response. As part of earlier influenza research, her team has built a network of more than 70 healthcare facilities across the country, collecting in-depth medical chart data.

Having that network in place allowed Feldstein to respond quickly when, for example, reports of the severe response in children began to emerge. Within 10 days, her team had documented 213 potential cases in the U.S. “We worked round the clock to analyze it and write it up so that we could help clinicians recognize these cases and inform how they should treat them,” she said.

Feldstein first became interested in epidemiology while at Colby, where she majored in international studies and French. The turning point came during her senior year when she enrolled in a history of epidemiology course taught by James L.A. Webb Jr., now professor of history, emeritus. “I didn’t know what epidemiology was until I took that class, and I loved it,” she said. “I loved learning about infectious diseases and their impact on society and history.”

In 2010, after spending two years in healthcare consulting, focused mainly on chronic diseases such as asthma and diabetes, she embarked on a year volunteering as an English and science teacher in the Federated States of Micronesia. There, a mumps outbreak made her realize she wanted to go back to school. Helping with prevention tactics such as public education and vaccine access, she found she liked the challenges of determining where and how disease spreads, along with how to stop it.

“It really is like doing detective work,” she said. “You can propose, implement, and assess prevention and control measures, and that’s the piece I find incredibly fascinating and rewarding.”

She earned a master’s degree in control of infectious diseases at the London School of Hygiene and Tropical Medicine before completing her Ph.D. in epidemiology at the University of Washington in 2016. Her entry to the CDC followed soon afterward through the Epidemic Intelligence Service, a two-year fellowship within the agency that she credits with helping to launch her career.

In her early work at CDC, Feldstein investigated diverse outbreaks ranging from diphtheria in camps of Rohingya refugees from Myanmar to pneumococcal meningitis in an Alabama state prison. She thought studying influenza might be boring—until she joined CDC’s Influenza Division and realized the virus fascinated her. “It is constantly changing,” she said. “There are a million questions about it that will help us understand more about the [flu] virus and infectious diseases in general.” Unlike influenza, coronavirus can be transmitted asymptomatically, which makes it very tricky to control. “This virus differs from any other  respiratory virus we’ve seen before,” Feldstein said.

In addition to her work on coronavirus in children, she is examining infections and risk factors among healthcare workers. Eventually, she will be able to continue her research on influenza and incorporate coronavirus as well. When a vaccine for the latter is released, for example, she will adapt her research to evaluate vaccine effectiveness for both viruses.

In the meantime, she is absorbed in the current fight to understand and contain the pandemic, an exhausting endeavor with no end yet in sight. For balance, she tries to stay connected to family and friends, getting out into nature whenever she can and taking time on the weekends for herself.

If there is a silver lining in this moment, it might be the opportunity to grasp a concept epidemiologists have long tried to convey: that when you get a vaccine or wear a mask in public, you are participating in public health for the common good, protecting not just yourself but others as well.

“My personal opinion is it would be great if we could shift our perspective from that of the individual toward more of a community perspective,” she said. “This pandemic has taught us that we are very much all connected, and that what we do here matters all over the world.”