Coronavirus: Why Did It Catch Us Off Guard?

Infectious disease expert Greg Gray, MD, MPH, FIDSA, discusses why COVID-19 spread so quickly, why it’s so deadly compared to other viruses, and what we should be doing to prevent another pandemic.

Dr. Gray is an infectious disease epidemiologist, professor of medicine in the Division of Infectious Diseases, and member of the Duke Global Health Institute.


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Lindsay Key: Welcome to HeadScratchers, a minicast from the Duke University School of Medicine. We ask Duke experts to help us understand the questions in science that have us scratching our heads. Today we're speaking with Dr. Greg Gray, an expert in infectious disease. 

Dr. Gray, the coronavirus has spread quickly around the globe. What makes this virus so special? Why did it catch us so off guard? 

Dr. Gray: Well, this virus is unique in that 100% of people, essentially, are susceptible to infection. And it is highly infectious. And it has a long incubation period. It's a real super challenge, if you will. It's difficult to control.

LK: As an infectious disease researcher, is this epidemic that we're experiencing? Is it something that you thought might happen one day or were you really surprised by it?

GG:  Yeah, I think those of us in infectious disease epidemiology recognize that in the last 25 years, we've had seven or so of these events. This is not the first one. And it's a repetitive issue: we see the emergence of a virus that causes an epidemic in man, we try to understand it, we mitigate it. And we do the best that we can to put out the fire. 

So what can we do when the next virus surfaces? We need to do a better job. What we need to really be doing is looking at the human-animal interface and monitoring for novel viruses that might emerge from that interface. Looking at people who have close contact with animals and seeing when they have evidence in their respiratory tract of a new virus that's emerged from the animals, and then making preparations way before the virus cycles over and over and becomes highly infectious to man. And we can do that -- and the way to do it is through something called One Health. Working together with human health, veterinary health, environmental health on specific problem areas like these, to get ahead of this, so we're not always responding to the latest threat. Often we've been to that in partnership with the animal industries, animal production industries. You might not know it, but there have been three emerging coronaviruses that really had a big negative impact on the swine industry, they've not affected humans. But we could help, and at the same time we're looking for novel viruses that would have an impact on humans, we could help them get a handle on the viruses that are going to only cause deaths in their animals. 

We talk about zoonosis as a pathogen that causes disease. And usually we talk about a pathogen that moves from animals to man. But we can also see zoonosis, sometimes called reverse zoonosis, where a pathogen that is normally affecting man moves to the animals. And that's another reason to do One Health -- because understanding zoonosis, we can help not only human health, but animal health and the animal industries. 

So, Duke has been a great place to do the research we do, because Duke is very forward thinking and we're very connected to the Global Health Institute. And we have studies right now in about 14 countries and many of these studies are looking for zoonosis. Right now we're doing big studies and northern Vietnam. We just wrapped up a study in Yangon, Myanmar. We're wrapping up a study that was conducted in South Africa. And over the last several years, we've done studies in many different places. 

Yeah, we’ve found some pretty unusual things right now that we're still working them up -- some viruses that shouldn't be in humans, and unless you look for them, you can't easily find them. But we're able with some of the technologies that we've adapted or developed here at Duke to do so.

LK: Thanks for listening. This podcast was produced by the Duke University School of Medicine. Music by Blue Dot Sessions. Visit us online at You can also find us on all your favorite podcast players. Don't forget to hit the Subscribe button -- and if you like us, leave us a review.

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