Measles, mumps and misinformation: how Crunchy Moms became ‘the most dangerous’ group on Facebook - The Guardian

By Google News Technology · 2026-11-06T21:22:00+01:00

Exclusive: Meta says it removes content that could cause imminent physical harm – but nearly half a million members have joined a group that regularly promotes misinformation

As a measles outbreak spread through Lancaster county, Pennsylvania, in August, a parent turned to a massive public Facebook group, Crunchy Moms, for advice. They were considering getting their three-year-old vaccinated, in part to protect their six-month-old.

“I’m nervous for my baby,” the parent wrote.

“First of all your children cannot die of measles. It is literally impossible,” one member responded. “Do not do it,” advised another. Others said the vaccine would spread measles or that it would be like “injecting poison”.

At the end of the post, Facebook’s AI system – run by its parent company, Meta – summarized the 589 responses, writing in part that commenters “claim the vaccine is unnecessary or even harmful”.

None of those claims are true. Pennsylvania has reported six measles-associated deaths this year, including two babies in Lancaster county. The measles, mumps and rubella (MMR) vaccine is safe and effective. Health officials say it is the best defense against measles spreading and injuring or killing people.

Scientists, doctors and advocates for health and children’s safety told the Guardian that what they saw in Crunchy Moms and similar groups was alarming. They worried that children could be getting hurt and that mothers were getting pulled into an online community that rejected science and fact-based medicine. One scientist who spends her free time monitoring the platform to highlight harmful health misinformation calls Crunchy Moms “the most dangerous group on Facebook”.

Meta did not comment on that characterization.

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Originally published by Google News Technology