Scientists refine argument that coronavirus originated in Wuhan market – The Washington Post | Region & Cash


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

The release of the papers, which have been peer-reviewed and revised by the authors for five months, are unlikely to quell the bitter debate over how the pandemic began and whether the virus originated in a Chinese lab. And the authors concede that there are many unknowns that require further investigation — most notably which animals were involved.

“Everything upstream — what animals, where they came from, how it’s all connected — is completely unknown at this point,” Kristian Andersen, an immunologist at Scripps Research, said in a Tuesday news conference.

“Have we disproved the lab leak theory? No we have not. Will we ever be able to? no But there are “possible” scenarios and there are “plausible” scenarios. … “Possible” does not mean the same as likely,” Andersen said.

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

The “Lab Leak” allegation was initially dismissed as a conspiracy theory in most mainstream media. Laboratory leak scenarios abound, and many have focused on the Wuhan Institute of Virology, a major research center studying coronaviruses.

Scientists there say they never had the virus in their lab. However, external experts doubted that the laboratory adhered sufficiently to security measures when researching viruses. Chinese authorities restricted access to the labs for outside investigators. Amateur detectives created online communities that constantly raised suspicions of a possible lab leak. The pressure to examine the hypothesis arose amidst the scientific community’s struggles to determine how the virus got into the human population.

In May 2021, Science magazine published a letter from 18 scientists calling for an investigation into the origin of the virus that would include examining the theory of laboratory leaks. Soon after, President Biden asked his intelligence agencies to investigate all possible causes of the pandemic. The review concluded that the virus was not an engineered bioweapon, but otherwise could not come to a conclusion as to where it came from.

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 off the market. Worobey is the lead author of the new paper, which claims the market was the epicenter of the pandemic.

The researchers sifted through data on the earliest patients, many of whom had direct links to the market or lived nearby. The geography of the early spread in the community showed infections radiating from close to the market, Worobey said: “It’s an insane hit.”

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

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

Worobey is not new to this topic. Last year, he wrote a “Perspectives” article in Science, in which he said the geographic cluster of cases in and around the market cannot be explained away as “investigation bias,” meaning the cluster is not simply the result of Investigators knocking on doors in the area after the market breakout was determined.

He considers any alternative scenario – such as a leak in the laboratory – to be implausible.

“This brings us to a point now where we know that the Huanan market has been the epicenter of this pandemic. That much is certain now. If others want to argue with that, they are now essentially taking a pseudo-scientific approach,” Worobey said in an interview on Tuesday. “Even if you didn’t smoke the gun of ‘Yes, we studied the raccoon dog with the virus in December,’ when you put it all together, it’s the only theory that actually explains all the data.”

Angela Rasmussen, a virologist at the University of Saskatchewan and a co-author of one of the new papers, said in an email that she agrees with Worobey: “There is no alternative explanation that fits the facts, so everyone trying to come up with one has to be an expert for willful ignorance, become a logical contortionist, or simply a fabulist.

The authors’ claim of a natural origin of the pandemic is not new: the same two articles in earlier form were posted online on a “preprint” site in February. But at that point, they existed in peer-review limbo — something that could be reported in a news story but didn’t have the stature of studies that have survived scrutiny by knowledgeable outsiders and journal editors.

The second paper, published Tuesday in Science, reports that genetic evidence and computer modeling suggest the virus entered the human population not once, but multiple times in late 2019 and must have come from separate spillovers. Both lineages have been found in environmental samples taken from the market, according to a February preprint paper by Chinese researchers.

Proponents of the lab leak theory disagree that the market was more of a superspreader site. For example, the virus could have been brought there by someone who is infected in a lab or by someone who was exposed to an infected lab worker.

The market origin argument also relies on Chinese data, which may be unreliable, said Jesse Bloom, a virologist at the Fred Hutchinson Cancer Research Institute, 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 any lab before it broke out in Wuhan. But the ongoing mystery surrounding the origin of the pandemic has drawn attention to the nature of virus research — including gain-of-function experiments — that some critics say is too risky. The US National Institutes of Health, which was embroiled in the controversy for helping to fund some research at the Wuhan Institute of Virology, said this year it would review its guidelines for ensuring lab safety.

Sen. Rand Paul (R-Ky.), who prefers a Labor origin explanation, said at an April 30 rally in Kentucky that if Republicans take power in the Senate after the midterm elections, he will use the power of a subpoena to “get to the bottom of where this virus came from.”

Chinese scientists have denied the virus was present in their lab. According to Andersen and other virologists who have studied it, the virus does not appear to have been engineered or manipulated, and its genetic traits may have arisen through evolution.

Nevertheless, the controversy surrounding coronavirus research is unlikely to die down.

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

On Tuesday, after Science published the two articles, Sachs said in an email that he still supports the lab leak theory: “The two competing hypotheses, natural spillover and lab generation, are both viable. They should be compared directly with each other. In my view, the laboratory creation hypothesis is the more direct and credible one.”

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

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

Andersen, the scientist at Scripps Research, has been embroiled in the controversy over the origin of the virus for more than two years. He was lead author of an early paper published in Nature Medicine and said the virus was clearly not tampered with. But his first impression of the virus was that it looked unnatural, and it was only after doing more research that he concluded that its traits might have arisen through evolution.

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

“Again, that’s not formal evidence, but in my opinion it’s so strong that any other version, say a lab leak, should be able to explain all that evidence,” he said. “It’s just not possible.”

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