Facebook has started pulling some misleading ads about an HIV-prevention medication after they were heavily criticized by activists and experts who warned that the social-media platform could spark a public-health crisis. The ads wrongly claimed that drugs designed to stop the spread of HIV could cause severe bone and kidney problems. Multiple studies show the class of medication—known as PrEP—is safe. The Washington Post reports that Facebook initially refused to disable the ads, which were linked to personal-injury lawyers and seen by millions of people. However, Facebook began on Friday to label some of the ads as rule violations in its archive, which limits their visibility, after the company’s third-party fact-checkers ruled the ads were misleading. “The removal of select ads is a strong first step given the findings of Facebook’s own fact-checking agency and the dozens of organizations that spoke out,” said Sarah Kate Ellis, the leader of LGBTQ media-monitoring group GLAAD.