The experts dismissed a lab leak theory.
For months, scientists, politicians and others outside China have promoted the theory that the virus might have emerged after a laboratory accident in China. While many experts doubt this theory, they have urged the W.H.O. team to rigorously investigate the possibility.
The report dismisses the lab leak theory outright, calling it “extremely unlikely.” The experts largely base their conclusion on conversations with scientists in Wuhan.
But Dr. Tedros, the W.H.O. chief, took the unexpected step of publicly raising doubts, saying that the theory required further investigation and that he was ready to deploy more experts to do so.
“I do not believe that this assessment was extensive enough,” he said on Tuesday at a briefing for member states on the report, according to prepared remarks released to the news media. “Further data and studies will be needed to reach more robust conclusions.”
The experts had said that officials at the Wuhan Institute of Virology, which houses a state-of-the-art laboratory known for its research on bat coronaviruses, assured them that they were not handling any viruses that appeared to be closely related to the coronavirus that caused the recent pandemic, according to meeting notes included in the report. They also said that staff members had been trained in security protocols.