Scientists Cast Doubt On Theory Coronavirus Came From Wuhan Lab : Short Wave The Trump administration has advanced the theory the coronavirus began as a lab accident, but scientists who research bat-borne coronaviruses disagree. Speaking with NPR, ten virologists and epidemiologists say the far more likely culprit is zoonotic spillover⁠—transmission of the virus between animals and humans in nature. We explain how zoonotic spillover works and why it's more plausible than a lab accident.

Scientists Think The Coronavirus Transmitted Naturally, Not In A Lab. Here's Why.

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MADDIE SOFIA, BYLINE: You're listening to SHORT WAVE from NPR.


Hey, everybody. Emily Kwong here. And today, I'm joined by senior science editor and correspondent Geoff Brumfiel. Hey, Geoff.


KWONG: So a few weeks ago, I reported on how virus hunters were able to trace the coronavirus to bats. But there's still this big unanswered question, which is, how did the virus jump from bats or another intermediate animal to humans?

BRUMFIEL: Right. So you may remember, back in January, we heard many of the earliest COVID-19 patients were connected to a seafood market in the Chinese city of Wuhan. But there's no evidence confirming that's where the virus got started. And, in fact, some of the earliest clinical patients had no connection to the market at all.

KWONG: And last month, the Trump administration began exploring various theories.


PRESIDENT DONALD TRUMP: There's a lot of theories. But, yeah, we have people looking at it very, very strongly.

BRUMFIEL: And the theory that President Trump has really landed on is this idea that the virus was released through a laboratory accident - that somehow a virus sample collected in nature later infected a person in a lab in Wuhan and then got out to the general population. Now, there are a lot of problems with this theory, as we will discuss. But Trump, when asked about it last week, said he had high confidence that this virus came from a lab.


UNIDENTIFIED REPORTER: Have you seen anything at this point that gives you a high degree of confidence that the Wuhan Institute of Virology was the origin of this virus?

TRUMP: Yes, I have. Yes, I have.

BRUMFIEL: And over the weekend, Secretary of State Mike Pompeo said the same thing. But neither he nor Trump have provided direct evidence.

KWONG: And you and I had already been wondering about the likelihood that this is true.


KWONG: So we spoke with 10 scientists - virologists, epidemiologists - and we kept hearing the same thing.

RAINA PLOWRIGHT: I think it's very unlikely.

SIMON ANTHONY: Just thinking about the way that we do this type of work, it would be very unlikely that this would be a lab exposure.

PETER DASZAK: The real risk is in the wild and the way people interact with wildlife around the world. And that's where we need to be focused if we want to really do something about preventing the next pandemic.

BRUMFIEL: That's Raina Plowright at Montana State University, Simon Anthony at Columbia University Medical Center and Peter Daszak of the EcoHealth Alliance, who's actually worked with the Wuhan lab. We spoke to these scientists back in April.

KWONG: So today on the show, scientists cast doubt on the lab accident theory, which they say would take a remarkable series of coincidences and deviations from well-established experimental protocols.

BRUMFIEL: And we explore the far more likely scenario that humans caught the virus outside of a lab and why some worry the lab theory could harm the kind of international cooperation we need to get a grip on this pandemic.


KWONG: OK. Today we're talking about the theory that the coronavirus began to spread through a lab accident. And because it's a developing news story, just a note, we're taping this on Tuesday afternoon. All right. Geoff Brumfiel, let's start with the Chinese lab at the center of all of this.

BRUMFIEL: So most of the focus has been on a place called the Wuhan Institute of Virology, this big research facility internationally recognized for its work on emerging infectious diseases. And it's particularly known for studying coronaviruses and bats.

KWONG: Yeah. And bats are definitely the likely origin of this outbreak. We know that this virus is 96% similar to a coronavirus found in horseshoe bats. And that's not quite as close as it sounds, but it's close enough to suggest that bats were the original source.

BRUMFIEL: By the way, Kwong, your episode on the bat-COVID connection was fantastic. SHORT WAVE listeners should definitely go back through their feed and find it.

KWONG: Why, thank you, Geoff.

BRUMFIEL: That's all you got for me, thank you?

KWONG: (Laughter) I don't know. Search for, "Where Did The Virus Originate? Virus Hunters Find Genetic Clues In Bats" (ph).

BRUMFIEL: There you go - all in the title, really useful. Anyway, this is where the theory basically comes from. The Wuhan Institute of Virology had a bunch of bat coronaviruses in storage. They're located, obviously, in Wuhan. And, you know, safety issues have happened in these high-containment laboratories with dangerous viruses in many parts of the world, including labs in China.

So U.S. intel agencies have been probing the connection. Now, they've ruled out the idea that this was some sort of laboratory-manufactured virus, that it was a bioweapon, that, you know, this is anything that's been genetically engineered. But what they haven't ruled out is the possibility that the virus came from nature, was collected by scientists and then subsequently escaped from a lab.

KWONG: And you and I started asking scientists whether this was plausible. And we found that most of them were actually quite skeptical.

BRUMFIEL: Right. And I think a good person to start with is Simon Anthony. He's one of the people you heard at the top there from Columbia. He and his colleagues estimate that, globally, bats are carrying around 3,700 coronaviruses.

KWONG: Holy bats. That's a lot of (laughter) coronaviruses.

BRUMFIEL: It is. It is. But what's important to understand before you freak out is that Simon told me very few of those viruses can actually make people sick.

ANTHONY: Most of the viruses, actually, probably don't even have the capacity to infect humans.

KWONG: Well, that eases my mind a little bit.

BRUMFIEL: Good, good. Well, I'm glad. But here's the thing. So this is coincidence No. 1 for a lab accident to be true. A researcher would have had to find a coronavirus in the wild that had already evolved in a way that was highly infectious to people.

KWONG: Which sounds, to me, pretty unlikely.

BRUMFIEL: Yes. Scientists collecting field samples from bats would sort of have to win the lottery. Although, I don't know that's entirely appropriate under circumstances. But basically, there's a small chance that you would just happen to collect this one coronavirus that makes people really sick. And it's also probably worth saying here that researchers at the Wuhan Institute of Virology explicitly say they did not have a coronavirus like this in their library.

KWONG: And that's important to mention because this gave them confidence the virus didn't come from their lab.

BRUMFIEL: Yeah. The first time they claimed to have ever seen this coronavirus is when hospitals in Wuhan sent them samples from patients trying to understand what was happening.

KWONG: OK. Geoff, what's coincidence No. 2?

BRUMFIEL: That scientists would have put themselves at risk of infection. Maybe it's not quite coincidence. But researchers are very, very careful when they go collect these samples. So I spoke to Jonna Mazet, a UC Davis professor who leads a global project on emerging diseases called PREDICT. And here's how she described what they do to get ready to go out.

JONNA MAZET: So we wear boots, Tyvek, N95 masks, eye protection, covered heads. And everything is also duct taped to make sure that, you know, that there is no gap between the gloves and the Tyvek suit.

BRUMFIEL: So they're all suited and booted. And they go to swab these bats. They're wearing really heavy leather gloves when they do so they can't get bitten or scratched. And they immediately plunge these samples that they get into liquid nitrogen. They freeze the virus. And when they get back to the lab, they actually only work with a virus sample that they've already killed.

KWONG: Yeah. They inactivate the virus, which is this chemical process where you basically break the virus apart but you preserve its genetic material for study.

BRUMFIEL: Right. It can't be brought back. Now, they do keep a tiny amount of live sample that they sort of have on file for reference. But it's kept on ice. It's almost never taken out of the fridge. And, you know, even on the rare occasions over the years that scientists have tried to take it out and grow it, it doesn't always work because there's so little virus in the sample. These rigorous protocols were used in Wuhan, at least according to the scientists that we spoke to who have worked directly with the lab.

KWONG: So assuming all these protocols were followed, the lab accident theory is kind of on thin ice. But what if there was a mistake, because lab accidents have happened in the past, right?

BRUMFIEL: They have. In fact, in the 2000s, there were several cases of the original SARS virus escaping from a laboratory environment in China, in Taiwan and in Singapore. But as far as I understand it, those escapes tended to happen when there were much larger quantities of virus being grown or when there was some sort of serious shortcoming in the biosecurity protocols or both. Now, there are some even more unusual scenarios that have been floated, but there's no public evidence backing those theories, so we're going to leave them aside for now.

KWONG: So bottom line, scientists think the odds are really slim.

BRUMFIEL: Yes. And I think it's important to just say here that intelligence agencies do employ people with scientific backgrounds. But they think about the world differently. I mean, the job of an intelligence service is to pursue a lot of different theories, even remote theories, so that the government isn't caught by surprise.

KWONG: Right. But the scientists we spoke to, they looked at this a little differently. They think the lab theory is very remote and that there is a much more likely scenario, a so-called zoonotic spillover event.

BRUMFIEL: Which is the case where humans encounter bats or another animal in nature and they get sick.

KWONG: Yes. Spillover events happen in three ways - one, through feces, through poop. So a person coming into contact with bat guano or other animal feces. The second way is through slaughter, so butchering and eating wild game. And the third way is vector-borne, so basically a virus being transmitted to a human through an animal bite.

BRUMFIEL: And human-wildlife interactions have created the perfect storm sort of for spillover events in the past. Think about the Ebola virus, the Hendra virus and other known coronaviruses like SARS and MERS. They were all spillovers.

KWONG: Yes. And they can happen especially in China and other countries where high-density populations are changing the landscape, and where you can see crops butting up against wilderness or there's livestock and wildlife trade - basically, anything where humans are interacting with animals.

PLOWRIGHT: We're fragmenting habitats. We're building roads through most regions of the world. We're incrementally destroying the large landscapes that animals have to live in.

KWONG: That's Raina Plowright again, who is also the principal investigator of the Bat OneHealth research group. She says we may never know exactly where this virus came from. But Occam's razor tells us...

BRUMFIEL: Oh, I love Occam's razor. Such a science friend. I feel like I'm in a safe space right now, Kwong.

KWONG: You are in a safe space, Geoff, because Occam's razor would say that the simplest solution is most likely the right one.

PLOWRIGHT: What is most likely? What does the abundance of evidence suggest? In this case, the abundance of evidence suggests this is a virus that has had natural selection in bat populations and has spilled from bats either into another species and then humans or perhaps from bats directly into humans. And there's no doubt that is the most plausible situation for this pathogen.

KWONG: So that's why scientists believe we should be looking at zoonotic spillovers for the source of this coronavirus.

BRUMFIEL: And here's where the researchers we talk to say the politics and science really collide. I mean, to find the natural source of the virus in China, we need to cooperate with scientists in China at places like the Wuhan Institute of Virology. And collaborations like that are coming under fire because of things like the lab accident theory.

KWONG: In fact, the Trump administration cut grant funding to EcoHealth Alliance's ongoing study of bat coronaviruses in China. And EcoHealth's president, Peter Daszak, told our colleague Nurith Aizenman that this kills their fieldwork and, of course, cuts off their access to Wuhan's library of coronaviruses and other pathogens.

DASZAK: We've got free and open access while we're doing this collaboration to get the genetic sequence of the viruses from those samples. But without the funding, we won't be able to get that. So we're now going to be unable to assess the real risk of danger of the next outbreak without this funding.


KWONG: So that's Daszak's biggest concern. What do you think is the implication of a funding cut like this?

BRUMFIEL: Well, I mean, the Trump administration's defenders would say he's cutting funding to a lab that they are worried is at the center of this whole thing. But scientists doing the work say they're worried the U.S. is actually cutting itself off from ever knowing the true origin of the virus and that this move could potentially damage the entire infrastructure around stopping global disease. It potentially weakens our ability to understand both COVID-19 and future pandemics.

KWONG: Geoff, thank you so much for reporting this and looking into this with me.

BRUMFIEL: The same to you, Emily. Thanks.

KWONG: I'm Emily Kwong. You've been listening to SHORT WAVE from NPR. This episode was produced by Abby Wendle, edited by Viet Le and fact-checked by Emily Vaughn. And, by the way, if you've liked what you've heard, please subscribe to SHORT WAVE. That way, we can keep our content coming your way. See you next time.


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