Scientists claim that the coronavirus came from a market in Wuhan

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

The publication of the papers, which came after five months of revisions and revisions by the authors, will not quell the debate over how the pandemic originated and whether the virus originated in a Chinese laboratory. And the authors acknowledge that there are many unknowns that require further investigation — most importantly, which animals were involved.

“Everything on top of that is which animals, where they came from, all of that is completely unknown at this stage,” Christian Andersen, an immunologist at Scripps Research, said in a briefing Tuesday.

“Have we ruled out the lab leak theory? No we haven’t. Will we ever get one? Name. But there are ‘possible’ scenarios and ‘plausible’ scenarios. … ‘Possible’ doesn’t mean equally likely,” Andersen said.

A natural origin of pandemics – “zoonosis” – has long been a favored theory among scientists, as most pandemics, including the SARS coronavirus outbreak of 2002-2003, began this way. Andersen and his colleagues suggest that several lines of evidence, including the clustering of early cases of Covid-19 around the market, are the only possible scenario that fits the data, rather than the market’s origin.

The “lab leak” hypothesis was initially dismissed as a conspiracy theory by most media outlets. There are many scenarios for a lab leak, and most of them have focused on the Wuhan Institute of Virology, a major research center for the coronavirus.

According to scientists there, the virus has never been in their lab. But outside experts have questioned whether the lab is taking adequate precautions when researching viruses. Chinese authorities have restricted the access of outside investigators to the laboratories. Enthusiasts have formed online communities, constantly raising suspicions about possible leaks from the lab. The pressure to investigate the hypothesis comes as the scientific community struggles 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, which included investigating the theory of a lab leak. Shortly thereafter, President Biden asked intelligence agencies to investigate all possible sources of the pandemic. The review concluded that the virus was not an engineered biological weapon, but was otherwise inconclusive about 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 said the thesis that leaked out of the lab was worthy of attention, even if it was not the most likely origin. However, Vorobey was soon convinced that the virus was out of the market. Vorobei is the lead author of a new paper that claims the market was the epicenter of the pandemic.

The researchers examined data from the earliest patients, many of whom had direct contact with the market or lived nearby. The geography of the initial community spread showed infections spreading outward from around the market, Warobey said.

Furthermore, when the market was first identified as the site of the cluster cases, Chinese investigators took environmental samples looking for traces of the virus. A disproportionate number of positive virus traces came from the part of the market where live animals were sold, according to a new study.

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

Worobey is not new to this issue. Last year, he wrote a “Perspective” article in the journal Science that argued that the geographic clustering of cases in and around the market could not be explained by “detection bias,” implying that the clustering was not the result of investigators knocking on doors. post-market area.

He believes that an alternative scenario such as a leak from the lab is unlikely.

“Now this has brought us to the point where we know that Huanan Market is the epicenter of this pandemic. That much has now been determined. If others want to argue with that, they’re actually using a pseudo-scientific approach,” Worobey said in an interview Tuesday. “Even if you don’t have the smoking gun of, ‘Yeah, we got a raccoon dog sample with the virus in December,’ when you put it all together, it’s the only theory that 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 alternative explanation that fits the facts, so one has to try to invent one. one has to be a master of willful ignorance, a logical contortionist, or simply a fabulist.”

The authors’ argument about the natural origin of the pandemic is not new: two previous papers were published online in February on a “preprint” site. But at the time, they were peer-reviewed—something that could be reported in the news, but lacked the level of peer-reviewed research by outside academics and journal editors.

In a second paper published Tuesday in the journal Science, genetic evidence and computer modeling suggest that the virus may have spilled into the human population not just once, but several times in late 2019. Genomic analysis of early cases shows two distinct lineages, called A and B. should have been poured separately. According to a paper prepared by Chinese researchers in February, both strains were found in environmental samples taken from the market.

Promoters of the lab leak theory believe that the market may be a superspreader site. The virus can be brought there by a person infected in a laboratory or by a person exposed to an infected laboratory worker.

In an interview earlier this year, Jesse Bloom, a virologist at the Fred Hutchinson Cancer Research Institute, said the argument for a market origin also rests on Chinese data. He said he found the data “inconclusive.”

“I think the information published by the Chinese government should be taken with a grain of salt,” Bloom said.

There is no evidence that the virus or its progenitors existed in any laboratory prior to the outbreak in Wuhan. But the mystery of the pandemic’s origins has focused on the kind of research some critics say is done on viruses, including “gain-of-function” experiments. The U.S. National Institutes of Health, which has come under fire for helping to fund some research at the Wuhan Institute of Virology, said this year it is reviewing its policies to ensure laboratory safety and security.

You are. Lab derivation advocate Rand Paul (R-Ky.) said at a rally in Kentucky on April 30 that if Republicans take control of the Senate after the midterms, he will use his subpoena power to “get to the bottom of it.” This is where the virus came from.”

Chinese scientists have denied that the virus exists in their laboratory. According to Andersen and other virologists who study it, the virus is not controlled or engineered, and its genetic characteristics may have evolved.

Still, the debate over coronavirus research continues.

Columbia University economist Jeffrey Sachs, who chairs a commission funded by the Lancet journal, is expected to issue a report this fall on the pandemic, including the origins of the virus. He recently co-authored an article in the Proceedings of the National Academy of Sciences calling for an investigation into the origins of the pandemic through a “bipartisan congressional inquiry with full investigative powers.”

On Tuesday, after Science published the two papers, Sacks said in an email that he still supports the lab leak theory: “The two competing hypotheses, natural spread and lab creation, are both viable. They should be directly compared to each other. My In my opinion, the hypothesis of creating a laboratory is the simplest and most reliable.

The new documents don’t declare “case closed,” but they are helpful, noted Stanford University professor of medicine and microbiology David Relman, one of the signatories of a 2021 letter calling for Science to investigate the origins of all possible pandemics. He said he would like to see a similar thorough forensic study of the lab leak hypothesis.

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

Andersen, a Scripps research scientist, has been at loggerheads over the origin of the virus for more than two years. He was the lead author of the first paper published in the journal Nature Medicine, which said the virus was not exactly engineered. But his first impression of the virus was that it looked unnatural, and only after more research did he conclude that its features might have evolved.

On Tuesday, Andersen reiterated that he initially thought the novel coronavirus had emerged from a lab. But all signs point to a market now, he said.

“Again, this is not official evidence, but I think another version, such as a lab leak, should be able to explain all of this evidence,” he said. “It is impossible.”

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