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Monday, September 13, 2021

Most scientists dismiss the lab leak conspiracy theory

A recent review in Science has the following subtitle, "Why most scientists say it's unlikely that SARS-CoV-2 originated from a lab leak." The title of that article was Call of the Wild but on the Science website it's The hunt for SARS-CoV-2’s ancestors heats up. The website article is behind a paywall but the original magazine article is open access.

Most of the article deals with the speculation that workers at the Wuhan Institute of Virology (WIV) were secretly working with SARS-CoV-2 in 2019 and allowed it to escape and start a pandemic. It notes that this idea gained a lot of traction in the media last Spring in spite of the fact that there was no evidence to support it. The author, Jon Cohen, points out that much of the unfounded speculation was political and that the accusations of lying and coverup have prompted calls for a thorough investigation of the WIV including an audit of everybody's notebooks, computers, and freezers.

"Chinese officials have scoffed at calls from Biden and WHO Director-General Tedros Adhanom Ghebreyesus for an independent audit of key Wuhan labs, which some say should include an investigation of notebooks, computers, and freezers. Chinese vice health minister Zeng Yixin said such demands show “disrespect toward common sense and arrogance toward science.” In response to the increasing pressure, China has also blocked the “phase 2” studies outlined in the joint mission’s March report, which could reveal a natural jump between species."

Conspiracy theorists will conclude that this is evidence of guilt but what if the scientists at WIV are telling the truth that they were never working with SARS-CoV-2 before the pandemic? Given that there's no evidence that these respected Chinese scientists are lying, how do you expect the Chinese government to respond? How would the American government respond to similar false accusations about the scientists at NIH? Would the Americans turn over all their lab notebooks and computers to foreign investigators?

The most prominent scientist at WIV is Shi Zhengli who got her Ph.D from Montpellier University in France. The scientists at the Wuhan Institute of Virology collaborated extensively wih French scientists to construct the modern biosafety level 4 (BSL-4) labs in 2014 at a cost of $44 (US). Since then, and before, they have been publishing well-received papers on the origin of SARS and other viruses with an emphasis on bat coronaviruses. Shi has denied any involvment with the SARS-CoV-2 virus before it was identified in sick patients at the end of December 2019 and, as far as I can tell, most knowledgeable scientists do not give any credence to the speculation that Shi is lying. For example,

Linfa Wang, a molecular virologist at the Programme in Emerging Infectious Diseases at Duke-NUS Medical School in Singapore who has collaborated extensively with WIV on bat coronavirus studies, has a simpler reason for dismissing the lab-leak hypothesis. “Accidents can only happen when you already have a live virus in culture that can leak,” Wang says. Bat coronaviruses are notoriously hard to grow. Shi told Science last year that her lab had more than 2000 bat fecal samples and anal and oral swabs that tested positive for coronaviruses. But the lab had only isolated and grown three viruses over 15 years, Shi said, and none closely resembled SARS-CoV-2. Some have questioned Shi’s veracity—she may well be under pressure from the Chinese government—and noted inconsistencies in her statements, but several scientific collaborators outside China have high regard for her integrity.

It's important to not lose sight of this important part of the lab leak conspiracy theory. In order for it to be true, scientists like Shi Zhengli and dozens of co-workers at the WIV have to be lying and participating in a coverup conspiracy that rivals pizzagate.1 That doesn't automatically mean that such a conspiracy is impossible but given the abundant evidence of a natural origin of SARS-CoV-2 you have to ask yourself what it is that motivates those who support the lab leak conspiracy theory?

"... many scientists say the existing evidence—including early epidemiological patterns, SARS-CoV-2’s genomic makeup, and a recent paper about animal markets in Wuhan—makes it far more probable that the virus, like many emerging pathogens, made a natural “zoonotic” jump from animals to humans.

Jon Cohen summarizes the evidence against all accusations made by the lab leak conspiracy theorists but none of this is new. The bottom line is that the vast majority of knowledgeable and reputable scientists reject the conspiracy theory. Most will soften their stance in print by saying that it's "highly unlikely" but in private they think the idea is ridicuous.

There's one persistent rumour that still attracts attention from those who are just now reading the Vanity Fair article by Katherine Eban or Nicholas Wade's article in the Bulletin of the Atomic Scientists. That's the idea that the furin cleavage site was artificially engineered. This silly idea has been debunked many times but I like the way Jon Cohen puts it.

The “smoking gun” evidence that SARS-CoV-2 was engineered, in the words of virologist and Nobel laureate David Baltimore, has not held up either. Spike has a cleavage site, a spot where a human enzyme named furin cuts the protein, which helps SARS-CoV-2 infect cells. Since early in the pandemic, lab-origin proponents have claimed that no SARS-related bat coronaviruses have this feature, leading to speculation that a lab added the site to a virus so it could infect humans. When retired New York Times writer Nicholas Wade made the case for a lab leak this spring, the furin cleavage site, buttressed by Baltimore’s provocative words, was an essential part of the argument.

But it’s dead wrong, say many coronavirus specialists and evolutionary biologists. The SARS-related coronaviruses are in the beta genus, one of four in the Coronaviridae family. Several members of that genus feature furin cleavage sites, which appear to have evolved repeatedly. And one SARS-CoV-2–related virus, described in a Current Biology paper last year by a team led by Shi Weifeng of Shandong First Medical University, has three of the four amino acids that constitute the furin cleavage site, which is “strongly suggestive of a natural zoonotic origin” for SARS-CoV-2, the authors concluded.

Baltimore has backpedaled the statement. He did not know several bat beta coronaviruses have the furin cleavage site, he acknowledged in an email to Science. “[T]here is more to this story than I am aware of,” he wrote. “The furin cleavage is the most ridiculous stuff,” Wang says.

We need more science writers who write like that. We also need fewer science writers like Katherine Eban and Nicholas Wade who publish articles about biochemistry and evolution in publications like Vanity Fair and the Bulletin of the Atomic Scientists.

The rest of the article addresses the most likely scenario for the origin of SAS-CoV-2; namely, that it spread from bats, to some animal that was probably sold in Wuhan's market, and then to humans. That's the scenario that almost all knowledgeable and reputable scientists support including evolutionary biologists like William Hanage at Harvard University.

The search will never lead us to patient zero, the first person to be infected by SARS-CoV-2, Hanage says. “Humans are looking for a story,” he says. “They want Columbo to come in and just somehow get somebody to confess or show what actually happened.” Instead, there are “possible stories” about SARS-CoV-2’s origin—some more probable than others—and stories that can be excluded, Hanage says. “And the space of possible stories in which there was a natural origin in or around the markets is much larger than the space of possible origins in which the Wuhan Institute of Virology is involved.”

1. Such clever conspirators could easily fudge noteboosk, wipe computers, and clean out freezeers so what's the point of an investigation?


Woody Benson said...

If the Chinese even vaguely suspected that the virus originated at WIV, can you imagine how quickly Beijing would have shut down the lab for decontamination?

Observer said...

Do we know what they did or didn't do? They took their virus database offline on 12 September 2019. It has subsequently emerged that Daszac's group had a proposal in 2018 which seems to envisage creating virus sequences similar to what has now emerged with SARS-2. See comments by the likes of Richard Ebright or Alina Chan, or the WHO geneticist commenting on the proposal.