The COVID-19 Lab Leak Debate Shows How Experts Failed Us

Americans’ response to the pandemic has reflected poorly on people who communicate science for a living. I would know: I write about science, and I graduated last month from Yale with a masters in public health and a concentration in microbial disease epidemiology. From this front-row seat, I’ve seen academic debates—typically held between scientists without the public ever taking interest in them—suddenly turn into messy public spectacles with societal effects. 

Case in point: a bizarre, seemingly tongue-in-cheek argument between comedians Stephen Colbert and Jon Stewart on Monday night regarding the origins of SARS-CoV-2, the virus that causes COVID-19, and the increasingly popular idea that it may have leaked from a lab.

“Science has, in many ways, helped ease the suffering of this pandemic,” Stewart said, turning his gaze from Colbert and speaking directly to the camera for effect, “which was more than likely caused by science.” The audience laughed, then applauded. 

Over the next four minutes, Stewart made the case that it was simply obvious that COVID-19 probably leaked from the Wuhan Institute of Virology, veering from glib jokes (“There’s been an outbreak of chocolatey goodness near Hershey, Pennsylvania, what do you think happened? Oh, I don’t know, maybe a steam shovel mated with a cocoa bean. Or it’s the fucking chocolate factory!”) to a monologue that seemed a lot more genuine. Colbert acted as a foil for public health and science communication professionals, raising his eyebrows and sipping his coffee in the background while pointing out that the presence of a coronavirus lab in Wuhan probably just means there are a lot of coronaviruses to study there. All the while, Stewart killed, and the studio audience cheered wildly.

This raucous late night discussion is the endpoint of over a year of failures on the part of science communicators. Early on, scientists didn’t do a good enough job of explaining masks—why, initially, scientists were worried that wearing homemade or cloth masks, for which there was little formal research, would lull people into a false sense of security. Coupled with fears of a mask shortage, the Centers for Disease Control and Prevention (CDC) recommended in March 2020 that healthy people do not have to wear masks. Then, after materials and aerosol research was conducted, experts pivoted ungracefully, highlighting the positive results of these studies without taking stock of the whiplash that the about-face caused the average American.

Something similar happened when reports from England about a new variant began circulating in late 2020, and experts cautioned not to read too much into the presence of mutations, which rarely represent an adaptive advantage. Now, that variant and others that have cropped up with increased transmissibility are taking hold in under-vaccinated regions.

In both these instances, the materials and aerosol scientists and virologists weren’t wrong, per se: they told us that more research needed to be conducted. However, the foot dragging that it took to change guidelines cost lives. The CDC acknowledged that SARS-CoV-2 can be spread through aerosol transmission in May, a year after preliminary research indicated this may be the case. 

Another problem was how these shifts were communicated—pundits, writers, and even other scientists or doctors with unrelated areas of expertise took one viewpoint with conviction, even wielding it as a rhetorical cudgel, only to later reverse course with equal conviction. 

Science values possibility, but people value certainty. So far, science communication hasn’t been able to bridge the two successfully. And during the largest public health crisis of a generation, that disconnect has had disastrous consequences. This discomfort with probability and an overreliance on false assuredness are the issues at the heart of the debate over the origins of SARS-CoV-2. 

Initially, the idea that the virus may have escaped from the Wuhan Institute of Virology was “debunked” by many media outlets and experts and treated as rank, and possibly xenophobic, conspiracy. And in many cases, it was. But recently, the tone of the conversation has shifted. Experts I interviewed for this article pointed to several reasons for this: a letter published by prominent researchers in the journal Science in May expressed dissatisfaction with a World Health Organization investigation into the virus’ origins; a Wall Street Journal article detailed a US intelligence report that three researchers at the Wuhan Institute of Virology sought medical care in November 2019 for unspecified symptoms; and an increasing proportion of vaccinated Americans freed up the emotional bandwidth for the conversation.  

Some media outlets have walked back their initial debunks to reflect more uncertainty about the possibility of a lab leak, others posted articles on the fresh controversy, and some observers have suggested that scientists and journalists were too quick to dismiss it early in the pandemic. When President Joe Biden announced in late May that he had ordered a closer intelligence review on the virus’ origins, proponents of the theory took it as corroboration of the theory’s validity. Even among skeptics, the sense of uncertainty grew. 

Unlike the conversations about masks and variants, this time, the evidence for a lab leak hasn’t changed. Which is to say: there isn’t any yet.

“I think almost everybody agrees that the facts are very thin,” said Marc Lipsitch, a professor of epidemiology at the Harvard T.H. Chan School of Public Health who co-authored the Science letter. “This is about the bounds of what's worth following up as a possibility, which is different from a standard scientific debate. It's how to interpret the scantiness of the evidence, rather than how to interpret the evidence.”

The scientists interviewed for this story advocated for further research and investigation into the origins of the coronavirus, including the possibility of a lab leak, but all agreed that there is currently no solid evidence suggesting anything other than a natural spillover event where a virus in animals managed to infect humans and spread in its new host. 

One such area of research involves discovering and sequencing bat viruses to find a naturally circulating SARS-CoV-2 common ancestor. Scientists have searched for this missing link since the start of the pandemic and not found a direct ancestor, but that is not necessarily out of the ordinary, Lipsitch said. It took nearly 15 years to find a progenitor of SARS-CoV-1, and the natural reservoir of Ebola virus has yet to be discovered.

However, it is a reality that lab leaks have happened before, in China and elsewhere. One prong of the lab leak theory involves gain-of-function research, a poorly defined category that includes a subset of experiments that add “pandemic potential” to a naturally occurring pathogen to gauge the likelihood of such changes occurring naturally. There was a moratorium on this sort of gain-of-function research in the U.S. from 2014 to 2017, but some have pointed to research from the Wuhan Institute of Virology that made recombined chimeras of coronaviruses as fodder for the lab leak hypothesis. 

Given this reality, and years of warning from scientists, the possibility of a lab leak cannot be eliminated in the absence of definitive proof or stronger evidence. Possibility and probability, however, are very different things, and humans are notoriously terrible at thinking about probability. 

“I love humanity, but we’re just not good at it,” said Arturo Casadevall, a microbiologist at Johns Hopkins. “There are people who are afraid of flying, but don’t wear a seatbelt on the way to the airport.”

Casadevall added that it can be tempting to think that because scientists haven’t yet found a smoking gun for a natural origin, say a reservoir of a close SARS-CoV-2 relative, that it’s evidence in favor of a possible lab leak. But that would be a mistake, he said. “The absence of evidence is the evidence of absence,” he said.

Proponents of the lab leak theory also point to what is called the furin cleavage site of the virus, which they say is a leftover of artificial creation. But we don’t know enough about coronaviruses to say if this is really uncommon, and it wouldn’t be the only “signature” left on it by human manipulation, said Casadevall. To grow a virus in a lab—even just to isolate it from a sample in nature—scientists must culture it on growth media, which are nothing like the respiratory tract of a bat, for example. Isolating anything in the lab introduces specific selective pressures that produce different end results than if it had been left in the wild, Casadevall said.

“For you to work on a virus, you need to bring it into a laboratory, you need to adapt it to grow in cell lines. That’s already a very different environment than the virus was in previously,” he said.

The letter in Science has been misinterpreted outside of scientific circles as explicitly supporting a lab leak hypothesis when it was only meant to ask questions and promote further research, Lipsitch said.

“I think it's fine to say there's no evidence right now for the lab leak hypothesis,” he said.

Even though the letter was meant to spark discussion among the scientific community, the discourse quickly spread to the general public. This outcome should have been foreseen, said Matthew Kavanagh, a global health professor and the director of the Global Health Policy and Politics Initiative at Georgetown University. Moreover, claims that it’s possible for this conversation to take place in an apolitical vacuum are “naive to an extent that’s dangerous,” he said.

“Scientists need to act with a level of political sophistication that is not necessary in most of their communications with each other, and that's really hard and not what science communication is equipped for,” he said.

Considering the role of politics includes thinking critically about why current and former US officials have been making anonymous statements to major news outlets about a possible lab leak, Kavanagh added, as well as why it may have been a savvy political move for Biden to cede to a vocal minority of Republican lawmakers and call for an investigation into the origins of the virus.

Future research into the virus will provide more context, at the very least. At most, Lipsitch said, it could dispel some of the misinformation about the virus’ origin and what we know.

“I think there's a reasonable chance that light being shed on this question will tamp down crazy discussions,” he said.

It’s also not necessary to wait for further research before taking preventative measures against potential future spillover events from nature or a lab, which are a constant risk regardless of SARS-CoV-2’s origins, Kavanagh said. Designing more robust surveillance systems to identify and curtail spillovers, and implementing extra degrees of safety when working with pathogens in the lab are not mutually exclusive, and they would both have clear benefits regardless of where this virus originated.

Casadevall said that he is optimistic that science will continue to learn more about the coronavirus. Still, we may never find the conclusive proof we’re seeking. We may need to learn to be as comfortable with possibility as scientists themselves are, he said.

“I think that science can help provide an answer, but I would be cautious that science may not give you a definitive answer,” he said. “All knowledge in science is provisional, and it may very well be that at the end of the day, you’re left with a probability.”

So, where does this leave us? One of the reasons, perhaps, that there has been renewed interest into this conversation is that discussing what we know about COVID-19—its ability to wreak havoc on the human body and the effectiveness and safety of the vaccines developed to prevent it—has begun to seem less urgent to some, and our attention has turned back to the unknowns. But it’s dangerous to think of this pandemic in the past tense, as vaccination rates in parts of the country lag and more dangerous variants spread internationally. What we know about this virus can help us fight it, while debating only what we don’t know to score rhetorical points on Twitter or in late-night comedy is a fool’s errand. 

One day, we may know the truth. But right now, armchair epidemiologists should act like real ones: support efforts to gather evidence, investigate the possibilities thoroughly, and most of all, keep a level head without jumping to conclusions.