The coronavirus probably spread from bats to humans via another animal, according to the long-awaited results of a joint World Health Organization-China study into the origins of COVID-19.
The authors suggest that the most productive research would be to find such an animal link, saying the hypothesis of lab leaks was extremely unlikely, according to a draft of the report, which was obtained by Bloomberg News before it's due to be published Tuesday. The scientists suggested future studies take a wider geographical approach, including Southeast Asia, and investigate susceptible animal species more closely.
The findings mirror what researchers said last month, at the end of their mission to Wuhan, the central Chinese city where the first COVID cases emerged at the end of 2019, and in their subsequent public comments. Possible host species include mink, pangolins, rabbits and ferret badgers, the report said.
The hunt for the virus's origin has been shrouded in controversy since the start of the pandemic. WHO Director General Tedros Adhanom Ghebreyesus said on Monday all hypotheses are on the table and warrant complete and further studies. The expert team will brief member states on Tuesday and will then publish the report to the public.
The Associated Press published comments from the report earlier. It was conducted by a team made up of both international and Chinese experts. The WHO has repeatedly said the report's conclusions are independent and belong to the authors.
While the search has become highly politicized, governments and scientists agree that deciphering the virus's creation story is key to reducing the risk of future pandemics. The research was aimed at galvanizing efforts to trace the origin of the virus that touched off the worst pandemic in more than a century, as well as its route of transmission to humans and the possible role of an intermediate animal host.
A spillover from bats via another animal is the most likely scenario in the report, followed by direct spillover. Introduction through frozen food was deemed possible, and a laboratory accident considered extremely unlikely.
Still, the report noted that the Wuhan CDC laboratory moved in early December to a location near the Huanan market, and "such moves can be disruptive for the operations of any laboratory."
However, the research center didn't report any disruptions or incidents that would have been caused by the move, and it wasn't storing or testing coronaviruses or bat viruses ahead of the outbreak, the report said. The authors also said that the three laboratories working in Wuhan on coronaviruses and vaccines had high biosafety levels and there was no evidence of COVID spreading among workers there.