This globetrotting doctor saves lives by diving headfirst into hot zones

When a virus strikes, epidemiologist Michael Callahan always seems to be in the thick of it. That's exactly how he likes it.

Photograph by Matt Nager, National Geographic
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Infectious disease expert Michael Callahan was embroiled in the fight against the COVID-19 pandemic even before news of the disease emerged in early January.

Photograph by Matt Nager, National Geographic

This globetrotting doctor saves lives by diving headfirst into hot zones

When a virus strikes, epidemiologist Michael Callahan always seems to be in the thick of it. That's exactly how he likes it.

In early January, when the first hazy reports of the new coronavirus outbreak were emerging from Wuhan, China, one American doctor had already been taking notes. Michael Callahan, an infectious disease expert, was working with Chinese colleagues on a longstanding avian flu collaboration in November when they mentioned the appearance of a strange new virus. Soon, he was jetting off to Singapore to see patients there who presented with symptoms of the same mysterious germ.

Name a major disease outbreak anywhere in the world in the last 20 years—SARS, Ebola, Zika—and chances are Callahan, 57, was there (in his biocontainment suit, of course). A stint working in a refugee camp in the Democratic Republic of the Congo during the 1990s convinced him to pursue work as a frontline infectious disease doctor. Since then, he has worked in remote Ebola clinics in Africa, helped retrain Russian bioweapons experts as infectious disease researchers, and led multimillion-dollar Department of Defense programs looking for ways to predict and preempt emerging diseases. (Find out more about how pandemics change us in National Geographic magazine.)

After Singapore, Callahan flew to Washington, D.C., where he briefed U.S. government officials on where the disease might occur next. By then, two cruise ships were stranded at sea with cases of coronavirus on board. Since Callahan was one of the few American doctors who’d seen the disease, the Department of Human and Health Services asked him to help evacuate American passengers from the Diamond Princess, off Yokohama, Japan, and the Grand Princess, off the coast of California.

Those missions completed, he returned to Boston—where he’s at based at Massachusetts General Hospital—and New York to help launch clinical trials and attend to Mass General’s own COVID-19 patients. “It’s an arms race between death and a cure,” he says. “Either the virus wins or our immune systems win.”

National Geographic caught up with Callahan while he was taking a break at his home in Boulder, Colorado. The following interview has been edited for length and clarity.

How did your background as a climbing bum at Yosemite prepare you for a life in infectious diseases?

I worked my way through college [at the University of Massachusetts Amherst] as a paramedic and got involved with mountain rescues, where I learned how to make the call when lives are at risk during emergencies. During medical school [at the University of Alabama], my interest shifted toward disaster operations overseas. I realized that it wasn’t the earthquake or tsunami that’s killing everybody, but it’s the malaria, the dengue, and waterborne diseases that come afterward. Infectious disease is a slow-rolling disaster. And it goes on forever.

Did you ever expect to see a pandemic like COVID-19 in your lifetime?

During planning exercises [at the Department of Health and Human Services] for outbreaks, we considered worst-case scenarios, but we always thought they were hypothetical. We were also certain that the next pandemic would be flu, even after the SARS outbreaks in 2002 and 2003. That was a bad virus, but it wasn’t that infectious. It goes to show how much humility you have to have.

What makes this new coronavirus so hard to fight?

Its magnificent infectivity. It sits there like a little silent smart bomb in your community, and then it finds a vulnerable person and just takes them out. I like to say the new coronavirus is all iceberg, no ice. It’s all beneath the surface of the water. We’re just mopping up the top of this thing right now.

How is this crisis changing the rules of medicine?

We have the most affluent, resource-rich medical system on the planet, but none of that richness is really helping us because our patients are dying at the same rates as they do in much less well-resourced nation. Our best weapon is knowledge.

Have you ever contracted an infectious disease in the field?

I consider it a professional failing to get infected. I’m supposed to be the best example. When we brought the disaster team [composed of doctors, nurse practitioners, nurses, and pharmacists sent by the DHHS] to the Diamond Princess cruise ship in Japan, they had never set foot in a hot zone in their entire life. These are earthquake people, hurricane people. They are learning new skills and we tell them the most important thing is to slow down if they are nervous or uncertain. If they get infected, the failure is on us, not them.

What keeps you returning to hot zones?

The last Americans to leave a hostile nation are doctors and nurses. We have a defective gene that makes us go to these outbreaks and put ourselves in harm’s way, because we are troubled by the inequality of health care access. During medical school, I volunteered at the Goma refugee camp on Congo’s border with Rwanda. I was back home when the genocide happened, but I became driven by the unfairness of it all. By going to these remote places and teaching one physician how to do something, I realized, I could affect a thousand lives and create lasting changes in a village or a community.

How do you think the coronavirus crisis will end?

The only way out of it is that everybody becomes immune because they’ve either got the infection or they got vaccinated. If I had to put my money down, one of the vaccines on the immediate horizon will give us transient immunity, and if it holds for four to six months, we’ll break the pandemic cycle. Then, we’ll do it again with another, better vaccine. So, we’ll live through it. We’re not going to knock it out of the park with the first vaccines.

Do you feel like there has been too much emphasis placed on the vaccine?

When you are faced with a mass casualty infection, there’s a priority list. First, protect the vulnerable. Second, break contagion. Third, treat the sick. And number four is make a vaccine, because it takes the longest and is the highest risk. But we haven’t broken contagion, quite obviously. And we’re not investing enough in coronavirus therapies. Developing a vaccine requires understanding the response of the human immune system to a virus we’ve never seen before. I would rather take the virus into the lab, and punch it out with a bunch of direct-acting antiviral drugs.

How can we prevent a pandemic like this from happening again?

Infectious disease outbreaks are becoming bigger, faster, and more frequent. Every Ebola outbreak [in Africa], people race to the capital cities, where there are direct flights to Europe and India and China. That means these diseases are instantly international, and we need to set aside politics and work together to fight them.