SAN FRANCISCO — Facebook says it will no longer remove claims that the coronavirus is human-made or manufactured “in light of ongoing investigations into the origin of COVID-19 and in consultation with public health experts.”

There has been growing pressure to investigate the origins of the pandemic, including the possibility that it came from a lab.

Since the pandemic began, Facebook has been changing what it allows on the topic and what it bans.

In February the social media company announced a host of new claims it would be prohibiting — including that coronavirus was created in a Chinese lab.

Other claims it added at the time included the false notion that vaccines are not effective or that they are toxic.

Lisa Fazio, a professor of psychology at Vanderbilt University, said the reversal shows the difficulty of fact-checking, particularly with something unprecedented like the coronavirus, when experts can disagree and change their minds with new evidence.

“It’s one reason that content moderation shouldn’t be static, scientific consensus changes over time,” Ms. Fazio said. “It’s also a reminder to be humble and that for some questions the best current answer is ‘we don’t know yet’ or ‘it’s possible, but experts think it’s unlikely.’”

Facebook announced the reversal as President Biden ordered U.S. intelligence officials to “redouble” their efforts to investigate the origins of the virus, including any possibility the trail might lead to a Chinese laboratory.

Facebook does not usually ban misinformation outright on its platform, instead adding fact-checks by outside parties to debunked claims. The two exceptions have been around elections and coronavirus.

First Published May 28, 2021, 3:27 a.m.