Investigation finds vaccine misinformation spreading unchecked in a large Facebook group

A large public Facebook group aimed at mothers interested in natural living has become a steady source of false medical claims, and Meta appears to have done little to stop it, according to an investigation by The Guardian. The group, called Crunchy Moms, now has more than 490,000 members and has more than doubled in size since January.

Reports went unanswered

A Guardian journalist flagged more than 50 posts and comments to Facebook from her own account in May, July and September. The material appeared to breach Meta's own rules and included claims that vaccines cause autism, that measles is not deadly, and that a caustic skin-destroying salve can cure cancer. According to the report, the platform did not act on or acknowledge any of them.

The investigation also found that Facebook itself had pushed the group into users' feeds, including the journalist's, without them searching for it. In one thread about a measles outbreak in Lancaster county, Pennsylvania, Facebook's AI tool summarised hundreds of replies by noting that commenters described the vaccine as unnecessary or harmful. Pennsylvania has reported six measles-associated deaths this year.

A shift in moderation

The findings come after Meta ended its US fact-checking programme and scaled back active moderation of all but the most severe or illegal content, following comments by Mark Zuckerberg that its platforms had too much censorship. The company told the Guardian its health misinformation policy and its enforcement have not changed since 2023. It said it removes false claims likely to contribute directly to imminent physical harm, while allowing discussion of personal experiences and research. It did not answer detailed questions about the group.

Researchers interviewed for the report said the situation resembles the period before the Covid-19 pandemic, when the platform recommended anti-vaccine groups to parents. Renée DiResta of Georgetown University said she feared seeing "that same kind of dynamic all over again." A former Facebook employee turned academic, Jennifer Allen, cited her own research estimating that exposure to vaccine-sceptical content on the platform during the pandemic lowered people's willingness to be vaccinated.

What it means for internet users

The case highlights how recommendation systems, AI summaries and user-reporting tools shape what people see on large social platforms, and how changes in moderation policy can affect the reliability of community spaces. For anyone using online groups for health or parenting advice, it underlines the value of checking claims against qualified medical sources and treating platform recommendations and automated summaries with caution.