A team of international virus experts working with Chinese counterparts failed to pinpoint the origin of the COVID-19 pandemic during a visit to China, amid mounting questions over stonewalling by Beijing and whether the virus escaped from a Chinese research laboratory.
The Biden administration and the head of the United Nations’ World Health Organization, which assembled the team behind the report, quickly aired doubts about the panel’s findings and said it was clear that more study was needed.
WHO Director-General Tedros Adhanom Ghebreyesus criticized authorities in China for limiting access to investigators and questioned the WHO team’s dismissal of the laboratory origin theory.
“I do not believe that this assessment was extensive enough …,” he said, according to a transcript of his remarks. “Although the team has concluded that a laboratory leak is the least likely hypothesis, this requires further investigation, potentially with additional missions involving specialist experts, which I am ready to deploy.”
Some of the report’s findings leaked earlier this week, and the WHO’s team leader acknowledged that many questions were left unanswered.
“At the end of the day, we didn’t find anything, but this is only a first set of studies,” team leader Peter Ben Embarek said in releasing the report at a press conference in Geneva.
Questions about whether the COVID-19 coronavirus leaked from a Wuhan laboratory — a scenario the authors rated as “extremely unlikely” and not worth further investigation — dominated the press conference, even though the joint WHO-Chinese report listed that theory as the least plausible of four scenarios it examined.
Separately, the Biden administration and 12 allied governments issued a joint statement expressing concerns that China did not support an open investigation and the need for more study.
“Together, we support a transparent and independent analysis and evaluation, free from interference and undue influence, of the origins of the COVID-19 pandemic,” the statement said.
The WHO report is part of a long-delayed effort by the U.N. health organization to find out the beginning of the COVID-19 pandemic, which has killed an estimated 2.8 million people worldwide.
“It remains to be determined where [COVID-19] originated,” the report said. “Although the virus was first identified as the cause of a cluster of cases of severe pneumonia in Wuhan, to date it is uncertain from where the first cases originated.”
China has been faulted for mishandling the outbreak by withholding data on the disease and not limiting travel by millions of Chinese during the Lunar New Year celebration last winter after the disease began spreading.
The government in Beijing prevented the WHO team from traveling to China until January. Once inside the country, team members were forced to undergo a two-week health quarantine. The team’s movement and activities were also restricted. Their report concludes that the virus most likely originated in 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: a direct “zoonotic spillover” from a bat to a human rated as “possible to likely”; the introduction of the virus from a bat to a host animal and then to humans, rated as “very likely”; the spread of the virus through frozen food packaging, a key Chinese official narrative, which 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.
The report called for further study in China on farms that raised wild animals for markets and for research on wildlife like bats and pangolins, which carry viruses similar to SARS-CoV-2, the coronavirus that causes COVID-19.
A laboratory leak of the virus was not ruled out, but the joint WHO-Chinese team said the focus of their probe was not on whether Chinese researchers may have mishandled a virus in one of several Wuhan laboratories, causing the disease outbreak, or that the virus escaped by accident.
China has staunchly denied that the virus leaked from the Wuhan Institute of Virology, home to the country’s sole high-security laboratory.
Team member Dr. Dominic Dwyer, with Westmead Hospital in Australia, said investigators were unable to conduct a thorough investigation of Wuhan labs. The coronavirus did not have to undergo research at a high-security laboratory and could have been studied at a less-secure laboratory, Dr. Dwyer said.
The team visit to the Wuhan Institute of Virology involved discussions with lab officials on biosecurity protocols. Based on the information from the Chinese, “we were satisfied there is no obvious evidence of a problem,” he said.
Mr. Ben Embarek said the lab officials provided no documents.
Chinese state media and international scientific journals in the past two years documented extensive research conducted at the Wuhan Institute of Virology and the Wuhan Centers for Disease Control, including “gain-of-function” research, which involves manipulating bat viruses to make them more infectious to humans in a bid to find vaccines.
A more thorough forensic investigation would be needed to determine whether 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.
The report said a laboratory accident was possible. Work in a lab with limited safety or poor management could have led to human infections from virus cultures or animal inoculations.
The Wuhan CDC laboratory moved to its location near the suspect Huanan market on Dec. 2, 2019. The report noted that “such moves can be disruptive for the operations of any laboratory.”
Researchers at the Wuhan CDC, according to Chinese state media, isolated more than 2,000 new viruses, including bat coronaviruses. The work there was led by Tian Junhua, who has been dubbed the “Bat Man of Wuhan” for his research. However, the report also noted that three laboratories in Wuhan working on bat virus isolation and vaccine development appeared safe.
“All had high quality biosafety level (BSL3 or 4) facilities that were well-managed, with a staff health monitoring program with no reporting of COVID-19 compatible respiratory illness during the weeks/months prior to December 2019,” the report said.
Mr. Ben Embarek suggested that 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, the final report was based on fair and vigorous debate and consensus among the experts.
The report said the virus may have emerged at the Huanan Market in Wuhan from a wild animal infected with the virus. None of the animal products sampled in the market tested positive for the virus, the report noted.
Animal sources that are possible hosts for the virus include bats and minks. However, the report found that “throughout 2020, there is no evidence of repeated introduction of early [SARS-CoV-2] strains of potential animal origins into humans in China.”
On the theory that the virus spread from frozen food packages, the report said no frozen food at the Wuhan market where the virus initially was thought to be a source was tested for the virus before it was closed in January 2020.
“There is no conclusive evidence for food-borne transmission of [the coronavirus] and the probability of a cold-chain contamination with the virus from a reservoir is very low,” the report said.
Many of the early cases of the pneumonialike 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 that he 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 cases might have been circulating around Wuhan as early as October and November 2019.
“That being said, the current thinking is we are looking at the start in Wuhan,” he told reporters Tuesday.
Chinese Foreign Ministry spokesman Zhao Lijian called Monday for WHO experts to visit the United States, including a military laboratory, as part of virus origin tracing.
China has claimed the U.S. Army brought the virus to China. The U.S. government has denied the charge.
Increased international attention on the virus originating from a Chinese laboratory, once ridiculed by experts as a conspiracy theory, is gaining wider acceptance.
Robert Redfield, a former director of the Centers for Disease Control and Prevention, broke with many scientific experts last week by saying he believes the virus likely escaped from a Chinese laboratory.
“I am of the point of view that I still think the most likely etiology of this pathogen in Wuhan was from a laboratory, escaped. The other people don’t believe that. That’s fine. Science will eventually figure it out,” he said on CNN.
The State Department in January published a fact sheet on the Wuhan Institute of Virology that said there is evidence that the virus came from the lab.
The fact sheet identified workers at the laboratory who became sickened with COVID-like symptoms in the autumn of 2019, work on the bat virus that is 96% similar to [SARS-CoV-2] at the lab and secret work by the People’s Liberation Army at the lab.
China is suspected of working on a covert biological weapons program, according to a State Department report released last year.
The U.S. and its allies said in their statement that the recent WHO study team in China “was significantly delayed and lacked access to complete, original data and samples.”
“Scientific missions like these should be able to do their work under conditions that produce independent and objective recommendations and findings,” the statement said.
Further study into the virus origin is needed and will require giving independent experts full access to all pertinent human, animal, and environmental data and research, and personnel involved in the outbreak.
Critics of the WHO team have pointed to its lone American expert, Peter Daszak of the New York-based EcoHealth Alliance, who has conducted extensive research at the Wuhan Institute of Virology.
Mr. Daszak has spoken out on social media against the theory that the virus leaked from a lab and has worked closely with the institute’s Shi Zhengli, known as the “Bat Woman of Wuhan,” for her work on bat coronaviruses, including laboratory manipulation of the viruses.