‘Covid-19 was probably a lab leak’, says ex-White House COVID response coordinator. What to know about the debate

Former White House COVID-19 Response Coordinator Dr Ashish Jha has said he now believes the COVID-19 pandemic was more likely caused by an accidental laboratory leak than a natural outbreak, while stressing that there is no definitive proof and that only Chinese authorities can conclusively determine the virus's origin.

Speaking to CNN's Dana Bash on Sunday (Aug 2), Jha said his assessment had changed since he joined the Biden administration. Bash referred to a recent post by commentator Jamie Metzl, which argued that the virus most likely originated from a lab leak at the Wuhan Institute of Virology. Jha had reshared the post on social media, writing that he agreed with its conclusions.

"This is going to surprise some people. When I went into the White House, my view was, 'This was almost surely a natural outbreak, maybe a lab leak,'" Jha said during the interview. "Based on information I learned and based on information I've seen, I have come to conclude that it is more likely to have been a lab leak."

However, Jha emphasised that his conclusion was an assessment rather than a confirmed fact.

"Here's the bottom line. No one in the United States knows for sure. The only people who know for sure are officials in China, and we still need transparency and accountability on that," he said.

“That is my best assessment. I'm not suggesting I know for sure, but I'm saying my best assessment is that it probably was a lab leak.” Responding to Jha's remarks, Bash said the comments reflected how understanding of the pandemic's origins continues to evolve.

Following the interview, Jha shared a clip of the discussion on X, saying his position was not new and that he had held the same view since his time in the White House. "My view on COVID origins isn't new. I've held it since my time at the White House," he wrote. "Here's the truth: no one in America knows for sure. Anyone telling you they do is selling you something. Based on strong circumstantial evidence I've seen, I think lab leak is much more likely. Not engineered. Not deliberate. Accidental. Reasonable people can look at the same evidence and disagree."

The origins of COVID-19 have remained the subject of global scientific and political debate since the pandemic began. Early in the outbreak, many scientists considered natural transmission, including the possibility of the virus spreading from animals to humans, to be the leading explanation. At the same time, the lab leak hypothesis was widely disputed and, in some cases, claims related to it were restricted by social media platforms under COVID-19 misinformation policies.