In March, as claims about the dangers and ineffectiveness of coronavirus vaccines spun across social media and undermined attempts to stop the spread of the virus, some Facebook employees thought they had found a way to help.

By altering how posts about vaccines are ranked in people’s newsfeeds, researchers at the company realized they could curtail the misleading information individuals saw about COVID-19 vaccines and offer users posts from legitimate sources like the World Health Organization.

“Given these results, I’m assuming we’re hoping to launch ASAP,” one Facebook employee wrote, responding to the internal memo about the study.

Instead, Facebook shelved some suggestions from the study. Other changes weren’t made until April.