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

There is rising pressure worldwide 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, it announced a host of new claims it would be prohibiting — including that COVID-19 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 in general, 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,” 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’s reversal comes as President Joe Biden ordered U.S. intelligence officials to “redouble” their efforts to investigate the origins of the COVID-19 pandemic, including any possibility the trail might lead to a Chinese laboratory. After months of minimizing these claims as a fringe theory, the Biden administration is joining worldwide pressure for China to be more open about the outbreak. It aims to head off GOP complaints that Biden has not been tough enough and to use the opportunity to press China on alleged obstruction.

“We’re continuing to work with health experts to keep pace with the evolving nature of the pandemic and regularly update our policies as new facts and trends emerge,” said Guy Rosen, Facebook’s vice president of integrity, in a statement Wednesday.

Facebook does not usually ban misinformation outright on its platform, instead adding fact-checks by outside parties, which includes The Associated Press, to debunked claims. The two exceptions have been around elections and COVID-19.