WASHINGTON (NYTIMES) – Scientists released a pair of extensive studies on Saturday (Feb 26) that point to a market in Wuhan, China, as the origin of the coronavirus pandemic.
Analysing data from a variety of sources, they concluded that the coronavirus was very likely present in live mammals sold in the Huanan Seafood Wholesale Market in late 2019 and suggested that the virus twice spilled over into people working or shopping there.
They said they found no support for an alternative theory that the coronavirus escaped from a laboratory in Wuhan.
“When you look at all of the evidence together, it’s an extraordinarily clear picture that the pandemic started at the Huanan market,” said Dr Michael Worobey, an evolutionary biologist at the University of Arizona and a co-author of both studies.
The two reports have not yet been published in a scientific journal that would require undergoing peer review.
Together, they represent a significant salvo in the debate over the beginnings of a pandemic that has killed nearly six million people globally and sickened more than 400 million.
The question of whether the coronavirus outbreak began with a spillover from wildlife sold at the market, a leak from a Wuhan virology lab or some other way has given rise to pitched geopolitical battles and debates over how best to stop the next pandemic.
But some outside scientists who have been hesitant to endorse the market origin hypothesis said they remained unconvinced. Dr Jesse Bloom, a virus expert at the Fred Hutchinson Cancer Research Centre, said in an interview that there remained a glaring absence of direct evidence that animals at the market had themselves been infected with the coronavirus.
“I think what they’re arguing could be true,” Dr Bloom said of the new studies. “But I don’t think the quality of the data is sufficient to say that any of these scenarios are true with confidence.”
In their new study, Dr Worobey and his colleagues present evidence that wild mammals that might have harboured the coronavirus were being sold in December 2019. But no wildlife was left at the market by the time Chinese researchers arrived in early 2020 to collect genetic samples.
The authors of the new study include researchers who previously published smaller reports that had pointed towards a similar conclusion but were based on much less detail. Their earlier analysis suggested that the first known case of the coronavirus was a vendor at the Huanan market.
In a separate line of research, scientists at the Chinese Centre for Disease Control and Prevention carried out a new analysis of the genetic traces of coronaviruses collected at the market in January 2020.
Previous studies have shown that the viruses sampled from early cases of Covid-19 belonged to two main evolutionary branches. The Huanan market samples included both branches, the scientists reported in a study they posted online on Friday.