Scientists back argument that coronavirus came from Wuhan market


The coronavirus pandemic began with separate viral fallout — at least two but possibly as many as two dozen — from live animals sold and slaughtered in late 2019 at the Huanan Seafood Market in Wuhan, China, according to two articles published Tuesday in the journal Science.

The papers’ publication, which has undergone five months of peer review and author revisions, is unlikely to quell the resentful debate about how the pandemic began and whether the virus is from a Chinese laboratory. And the authors acknowledge that there are many unknowns that require further investigation – including which animals were involved.

“Everything upstream of that – what animals, where did they come from, how everything is connected – is completely unknown at this point,” said Kristian Andersen, immunologist at Scripps Research, during a press briefing on Tuesday.

“Have we disproved the lab leak theory? No we do not have. Can we ever? No. But there are “possible” scenarios and “plausible” scenarios. … ‘Possible’ doesn’t mean equally likely,” Andersen said.

A natural origin of the pandemic – a “zoonosis” – has long been a theory favored by scientists for the simple reason that most pandemics, including the SARS coronavirus outbreak of 2002-2003, started that way. . Andersen and his colleagues believe that multiple lines of evidence, including the clustering of early covid-19 cases around the market, make a market origin not just a likely scenario, but the only one that matches the data.

The “lab leak” conjecture was initially dismissed in most mainstream media as a conspiracy theory. There are many lab leak scenarios, and many have focused on the Wuhan Institute of Virology, a major research center that studies coronaviruses.

The scientists there say they never had the virus in their lab. But outside experts have questioned whether the lab is sufficiently adhering to safety measures when testing for viruses. Chinese authorities have limited access to laboratories to outside investigators. Amateur sleuths have created online communities that have regularly raised suspicions about a possible lab leak. The push to investigate the hypothesis has come amid struggles by the scientific community to determine how the virus entered the human population.

In May 2021, the journal Science published a letter from 18 scientists calling for an investigation into the origin of the virus that would include exploring the lab leak theory. Soon after, President Biden instructed his intelligence agencies to investigate all possible origins of the pandemic. The review concluded that the virus was not an engineered bioweapon, but otherwise failed to draw a conclusion about its origin.

Among the scientists who signed the letter to Science was Michael Worobey, an evolutionary virologist at the University of Arizona who felt the lab leak thesis deserved attention even if it wasn’t. the most likely origin. But Worobey was soon convinced that the virus was out of the market. Worobey is the lead author of the new paper which argues the market was the epicenter of the pandemic.

Researchers scoured data on early patients, many of whom had direct ties to the market or lived nearby. The geography of early community spread showed infections radiating outward from around the market, Worobey said: “It’s a bull’s-eye insane.”

Additionally, when the market was first identified as the site of a cluster of cases, Chinese investigators took environmental samples looking for traces of the virus. A disproportionate number of virus-positive traces came from the section of the market where live animals had been sold, the new study reports.

“The virus started spreading among people working at the market, but then started spreading to the surrounding local community as vendors went to local shops and infected people working in those shops,” said suggested Worobey.

Worobey is not new to this issue. Last year he wrote a ‘Perspective’ paper in Science which said the geographic clustering of cases in and around the market could not be explained as ‘verification bias’ meaning the clustering was not not simply the result of investigators knocking on doors in this after market outbreak detection.

He thinks any alternative scenario – like a lab leak – is implausible.

“This now puts us at a point where we know Huanan Market has been the epicenter of this pandemic. It is now established. If others want to argue with that, they’re now basically taking a pseudo-scientific approach,” Worobey said in an interview on Tuesday. “Even if you don’t have the irrefutable gun of ‘Yes, we sampled the raccoon dog with the virus in December,’ when you put it all together, it’s the only theory that really explains all the data.”

Angela Rasmussen, a virologist at the University of Saskatchewan and co-author of one of the new papers, said in an email that she agreed with Worobey: “There is no other explanation that fits the facts, so anyone trying to find one will have to become a willful ignorant, a logical contortionist, or just a fabulist.

The assertion by the authors of a natural origin of the pandemic is not new: the same two articles in an earlier form were posted online in February on a “pre-publication” site. But at that time they existed in a limbo of peer review – something that could be reported in a news report but without the stature of studies that have survived scrutiny by knowledgeable outsiders and journal publishers.

The second paper published Tuesday in Science reports that genetic evidence and computer modeling suggest the virus spread through the human population not just once, but repeatedly in late 2019. Genomic analysis of the first cases shows two separate lines, called A and B, which had to come from separate spin-offs. Both lineages were found in environmental samples taken from the market, according to a preprint paper by Chinese researchers in February.

Proponents of the lab leak theory counter that the market was more likely a superspreading site. The virus could have been brought there by an infected person in a lab, or someone exposed to an infected lab worker, for example.

The argument for a commercial origin also rests on Chinese data that may not be reliable, Jesse Bloom, a virologist at the Fred Hutchinson Cancer Research Institute, said in an interview earlier this year. He said he thought the data was “inconclusive”.

“I think the data released by the Chinese government should be treated with a healthy grain of salt,” Bloom said.

There is no evidence that the virus or its immediate ancestor was in a laboratory before the outbreak in Wuhan. But the lingering mystery of the pandemic’s origin has drawn attention to the kind of virus research – including ‘gain-of-function’ experiments – that some critics see as too risky. The US National Institutes of Health, embroiled in controversy because it helped fund some research at the Wuhan Institute of Virology, said this year it was revising its policies to ensure safety and security laboratories.

Sen. Rand Paul (R-Ky.), who favors an explanation for the origin of the lab, said at an April 30 rally in Kentucky that if Republicans take power in the Senate after the mid-election mandate, he will use the power of subpoena to “get to the bottom of things”. where did this virus come from.

Chinese scientists denied that the virus was present in their lab. The virus, according to Andersen and other virologists who have studied it, does not appear to be manipulated or modified, and its genetic characteristics may have been produced by evolution.

Still, the controversy over coronavirus research is unlikely to fade.

Jeffrey Sachs, an economist at Columbia University, is leading a Lancet-sponsored commission that is expected to produce a report this fall on the pandemic, including the origin of the virus. He recently co-authored a paper in the Proceedings of the National Academy of Sciences calling for an investigation into the origin of the pandemic through a “bipartisan congressional inquiry with full investigative powers.”

On Tuesday, after Science published the two papers, Sachs said in an email that he was still supportive of the lab leak theory: “The two competing hypotheses, natural spillover and lab creation, are all two viable. They must be compared directly to each other. In my opinion, the hypothesis of the creation of a laboratory is the simplest and most credible.

The new papers don’t declare “the case is closed” but are helpful, noted David Relman, professor of medicine and microbiology at Stanford University who was among the signers of the 2021 letter to Science calling for an investigation. about all the possible origins of the pandemic. He said he would like to see such a thorough forensic investigation of the lab leak hypothesis.

“I don’t think we can say that we know now that it all started here. I think we can say something interesting happened in this part of town,” Relman said. “We don’t have any [coronavirus] positive animals at market.

Andersen, the Scripps Research scientist, has been embroiled in controversy over the origin of the virus for more than two years. He was the lead author of an early paper, published in Nature Medicine, saying the virus was clearly not engineered. But his first impression of the virus had been that it looked unnatural, and only after doing more research did he conclude that its characteristics could have been produced by evolution.

On Tuesday, Andersen reiterated that he initially thought the novel coronavirus likely originated in a lab. But all signs are now pointing to the market, he said.

“It’s not hard evidence, again, but it’s so strong in my opinion that any other version, a lab leak for example, should be able to explain all of this evidence,” he said. he declares. “It’s just not possible.”

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