A new surge of interest has revived the lab-leak theory. Well over a year since a novel coronavirus began to spread in Wuhan, the idea that the deadly outbreak could be linked to a virus research center in the Chinese city has lingered, unproven but not eliminated. Although the resurgent chatter may suggest new clues or proof, the inverse is in fact true. It is the persistent absence of any convincing evidence either for or against the theory that has prompted calls for more investigation.

President Biden said Wednesday that the U.S. intelligence community does “not believe there is sufficient information” to fully understand the likelihood of different scenarios for explaining the origin of the virus that causes covid-19.
The annual World Health Assembly this week brought new calls to significantly expand upon the WHO-backed investigation, which concluded in March. Biden on Wednesday announced that he was asking the U.S. intelligence community to “redouble its efforts” to collect information about the coronavirus’s origin.

The United States would continue to partner with “like-minded partners around the world to press China to participate in a full, transparent, evidence-based international investigation,” Biden said.

The public evidence for or against the lab leak is nowhere near decisive.

The lab-leak theory emerged in January 2020, when the virus was still mostly confined to China and had killed hundreds, rather than millions.

Links between WIV and the virus were floated in right-wing news organizations like the Washington Times, while former White House strategist Stephen K. Bannon questioned whether there was a link between the virus and “bioweapons research” in China.

Experts quickly dismissed the idea that the coronavirus was intentionally developed as a bioweapon, but vaguer questions about the link between WIV and the virus, including those asked by Sen. Tom Cotton (R-Ark.) in February 2020, were harder to answer.

In April 2020, journalists including The Washington Post’s David Ignatius and Josh Rogin suggested that a bat virus being studied in potentially risky experiments could have escaped the lab.