Coronavirus: How hackers are preying on fears of Covid-19
Security experts say a spike in email scams linked to coronavirus is the worst they have seen in years.
Facebook has said that a software issue was responsible for posts on topics including coronavirus being wrongly marked as spam.
The social media giant's head of safety said: "This is a bug in an anti-spam system."
The statement was in response to widespread complaints from Facebook and Instagram users.
It came a day after the firm said contract workers who review content would be sent home due to the outbreak.
"We've restored all the posts that were incorrectly removed, which included posts on all topics - not just those related to COVID-19," Guy Rosen, Facebook's vice president for integrity, said on Twitter.
The post came after complaints from users that they received notifications saying articles from prominent news organisations, including the BBC, Axios and The Atlantic, had violated the company's community guidelines.
The issue arose a day after Facebook announced that for public health reasons it was sending home all contract workers who perform content review services.