Facebook will no longer remove posts claiming COVID-19 was man-made, the company has told US website Politico.
It comes on the same day US President Joe Biden ordered an intelligence report on the virus origins to be delivered within 90 days.
"In light of ongoing investigations into the origin of COVID-19 and in consultation with public health experts, we will no longer remove the claim that COVID-19 is man-made from our apps," Facebook told Politico.
"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."
Meanwhile the company has announced it will now penalise individuals more as it attempts to combat the spreading of disinformation online.
Facebook started its fact checking programme in 2016 and is now expanding the penalties to individual accounts, it said in a blog post, but has largely penalised Pages and Groups for spreading misinformation, rather than individuals.
"Starting today, we will reduce the distribution of all posts in News Feed from an individual's Facebook account if they repeatedly share content that has been rated [as debunked] by one of our fact-checking partners," it wrote.
Previously individual posts would be down-ranked rather than every post from a user.
A study published earlier this year found that right wing fake news engaged Facebook users better than any other sort of fake news, or real news.
Pages which repeatedly share false claims will also be flagged by the new systems.
If users go to a page that has repeatedly shared false information, a pop up will be displayed indicating that, with users able to find out more information about the fact checking programme.
"This will help people make an informed decision about whether they want to follow the Page," the company wrote.