A team of international virus experts working with Chinese counterparts failed to pinpoint the origin of the coronavirus pandemic during a visit to China and called for further inquiry, in a report made public Tuesday.
“At the end of the day, we didn’t find anything, but this is only a first set of studies,” said World Health Organization team leader Peter Ben Embarek in releasing the report in Geneva.
The report concludes the most likely origin of the virus known as COVID-19 began from an animal infected with a bat-related pathogen — although no specific animal host that sickened the first suspect Wuhan residents in December 2019 could be identified.
Four possible sources of the outbreak were listed in the report in order of priority, including; a direct “zoonotic spillover” from bat to a human rated as “possible to likely”; the Introduction of the virus from a bat to host animal and then humans rated as ”very likely”; the spread of the disease through frozen food packaging — a key Chinese propaganda narrative — that experts considered “possible”; and an outbreak of COVID-19 from a laboratory incident that was gauged “extremely unlikely” — also reflecting a key Chinese government claim.
A laboratory leak of the virus being researched was not ruled out, but the joint WHO-Chinese team said the focus of their investigation was not on whether Chinese researchers may have mishandled a virus in one of several Wuhan laboratories that caused the disease outbreak.
China has denied the virus leaked from the Wuhan Institute of Virology (WIV), home to the country’s sole high-security laboratory.
Team member Dr. Dominic Dwyer, with Westmead Hospital, Australia, said during the press conference that investigators were unable to conduct a thorough investigation of the Wuhan lab. The coronavirus behind the pandemic did not have to be worked on at a high-security laboratory and could have been studied at a less secure laboratory, Dr. Dwyer said.
The visit to the WIV involved discussions with lab officials on biosecurity protocols and, based on the information given by the Chinese, “we were satisfied there is no obvious evidence of a problem.”
Mr. Ben Embarek said no documents were provided by the lab officials.
China state media and scientific journals have revealed extensive research has been conducted at both the WIV and the Wuhan Centers for Disease Control, including so-called “gain-of-function” research that involves making bat viruses more infectious to humans in a bid to find vaccines. A more thorough forensic investigation would be needed to determine if the virus escaped, Dr. Dwyer said.
“A true forensic investigation of a laboratory is a much more complex process, and that is not what we were there to do,” he said.
Mr. Ben Embarek suggested Chinese government officials who were present for meetings in China pressured the international team and sought to influence its final report.
“Nobody wants to have an origin of a pandemic in your backyard,” he said. However, he added that the final report was based on fair and vigorous debate and consensus among the experts.
The report said that the virus may have emerged at the Huanan Market in Wuhan from a wild animal infected with the virus.
Many of the early cases of the pneumonia-like disease were linked to the market, but the report said “many were not associated with any markets.” The team conducted extensive swabs of stalls at the market but was unable to pinpoint a specific type of animal that may have been carrying it.
China’s government, after initially claiming the virus began at the animal market, has shifted its narrative and begun claiming the virus came from outside China. Mr. Ben Embarek dismissed that theory as unlikely and said it is possible earlier cases were circulating around Wuhan in October and November 2019.
“That being said, the current thinking is we are looking at the start in Wuhan,” he told reporters Tuesday.