• David Leonhardt | The New York Times

The Lab-Leak Theory

We have an explainer.

David Leonhardt | The New York Times | May 27, 2021

Suddenly, talk of the Wuhan lab-leak theory seems to be everywhere.

President Biden yesterday called on U.S. intelligence officials to “redouble their efforts” to determine the origin of Covid-19 and figure out whether the virus that causes it accidentally leaked from a Chinese laboratory. Major publications and social media have recently been filled with discussion of the subject.

Today, we offer an explainer.

What are the basics?

The origin of the virus remains unclear. Many scientists have long believed that the most likely explanation is that it jumped from an animal to a person, possibly at a food market in Wuhan, China, in late 2019. Animal-to human transmission — known as zoonotic spillover — is a common origin story for viruses, including Ebola and some bird flus.

But some scientists have pointed to another possibility: that it escaped from the Wuhan Institute of Virology. As in other laboratories, researchers there sometimes modify viruses, to understand and treat them.

“It is most likely that this is a virus that arose naturally, but we cannot exclude the possibility of some kind of a lab accident,” Dr. Francis Collins, the director of the National Institutes of Health, told senators yesterday.

Why now?

The subject is getting more attention because some scientists who were once skeptical of the laboratory theory have expressed new openness to it.

Two weeks ago, 18 scientists wrote a letter to the journal Science calling for a new investigation and describing both the animal-to-human theory and the lab-leak theory as “viable.” And three scientists who last year dismissed the lab-leak explanation as a conspiracy theory have told The Wall Street Journal that they now consider it plausible.

Among the reasons: Chinese officials have refused to allow an independent investigation into the lab and have failed to explain some inconsistencies in the animal-to-human hypothesis. Most of the first confirmed cases had no evident link to the food market.

What changed?

In some ways, not much has not changed. From the beginning, the virus’s origin has been unclear. All along, some scientists, politicians and journalists have argued that the lab-leak theory deserves consideration.

Almost 15 months ago, two Chinese researchers wrote a paper concluding that the virus “probably originated from a laboratory in Wuhan.” Alina Chan, a molecular biologist affiliated with Harvard and M.I.T., made similar arguments. David Ignatius and Josh Rogin, both Washington Post columnists, wrote about the possibility more than a year ago. Joe Biden, then a presidential candidate, didn’t mention the lab-leak theory in early 2020 but he did argue that the U.S. should “not be taking China’s word” for how the outbreak started.

But these voices were in the minority. The World Health Organization initially dismissed the lab-leak theory as implausible.

Why all the dismissals?

It appears to be a classic example of groupthink, exacerbated by partisan polarization.

Global health officials seemed unwilling to confront Chinese officials, who insist the virus jumped from an animal to a person.

In the U.S., one of the theory’s earliest advocates was Tom Cotton, the Republican senator from Arkansas who often criticizes China — and who has a history of promoting falsehoods (like election fraud that didn’t happen). In this case, though, Cotton was making an argument with plausible supporting evidence.

The media’s coverage of his argument was flawed, Substack’s Matthew Yglesias has written. Some coverage exaggerated Cotton’s comments to suggest he was claiming that China had deliberately released the virus as a biological weapon. (Cotton called that “very unlikely.”) And some scientists and others also seem to have decided that if Cotton believed something — and Fox News and Donald Trump echoed it — the idea had to be wrong.

The result, as Yglesias called it, was a bubble of fake consensus. Scientists who thought a lab leak was plausible, like Chan, received little attention. Scientists who thought the theory was wacky received widespread attention. It’s a good reminder: The world is a complicated place, where almost nobody is always right or always wrong.

Why does it matter?

The virus’s origin does not affect many parts of the fight against Covid. The best mitigation strategies — travel restrictions, testing, contact tracing, social distancing, ventilation and masking — are still the best mitigation strategies.

But there are at least three concrete ways, in addition to the inherent value of truth, in which the origin matters.

First, if the virus really did come from a lab, an immediate airing of the details might have led to even faster vaccine development and more effective treatments. Second, a leak that caused millions of deaths could lead to widespread change in laboratories’ safety precautions. Third, confirmation of a leak would affect the world’s view of China — and would put pressure on China to bear the burden of vaccinating the world as quickly as possible.

So what’s the truth?

We don’t know. Both animal-to-human transmission and the lab leak appear plausible. And the obfuscation by Chinese officials means we may never know the truth.

For more: The Washington Post has published a helpful timeline. On Medium last week, the science writer Donald G. McNeil Jr. explained why he now finds the lab-leak theory plausible. And the sociologist Zeynep Tufekci has argued that the issue highlights some of the problem with the media’s approach to fact-checking.

The Times reports on the latest details about the inquiry Biden has ordered.