Ethan Lindenberger, who confided in a now-viral Reddit post that he had not been fully vaccinated due to his mother's belief that vaccines are dangerous, testifies before Congress on March 5.

Facebook announced Thursday that anti-vax misinformation will appear less frequently across people's News Feeds, public pages and groups, private pages and groups, search predictions, and in recommendation widgets around the site. The announcement comes after weeks of pressure from lawmakers and public health advocates to crack down on anti-vax content.



"We are exploring ways to share educational information about vaccines when people come across misinformation on this topic," Facebook said in its announcement. "Leading global health organizations, such as the World Health Organization and the US Centers for Disease Control and Prevention, have publicly identified verifiable vaccine hoaxes. If these vaccine hoaxes appear on Facebook, we will take action against them."

Following a measles outbreak in the Pacific Northwest in January, California Rep. Adam Schiff sent Facebook CEO Mark Zuckerberg and Google CEO Sundar Pichai a letter that outlined concerns with the way the big tech platforms surface anti-vaccine content and urged them to take action. Last month, after inquiries from from BuzzFeed News, YouTube said that it would prevent channels that promote anti-vax content from running advertising. The company said explicitly that such videos fall under its policy prohibiting the monetization of videos with “dangerous and harmful” content. And after Schiff published another open letter last week asking Amazon to reconsider featuring anti-vax content on its website, the company appears to have since removed anti-vaccination documentaries from Amazon Prime Video search results.

Facebook initially responded to Schiff's letter in February by saying that it was “working on additional changes” to “reduce the distribution of health-related misinformation,” but until today, it hadn't explained how it plans to do that. Now, the company says it will use machine learning and manual human review to identify and reduce specific kinds of anti-vax misinformation, such as the hoax that vaccines cause autism. Facebook also said it will be removing anti-vax groups and pages from the recommended groups and pages sections. These recommendation widgets have been a key way anti-vax communities have been growing on the platform.

Many of Facebook’s current tools for moderating misinformation and harmful content rely on the platform's flagging system, which some fact-checkers have criticized for being too simplistic. And one of the flagging system's specific shortcomings, when it comes to moderating anti-vax communities, is that the admins of anti-vaccination groups are unlikely to flag any sort of anti-vaccine content as “false news." Now, Facebook will take the same AI tools it relies on for reviewing and analyzing content in public feeds and use them inside of closed groups typically preferred by anti-vaxxers.

One of the most popular and prolific Facebook communities for anti-vaxxers is called "Stop Mandatory Vaccination," run by Larry Cook, the former executive director of the California Naturopathic Doctors Association. Over the past month, YouTube has demonetized Cook’s videos and his books appear to be recommended less often on Amazon. The public Stop Mandatory Vaccination and its adjacent private group are two of the larger spaces for anti-vaxxers on Facebook, and the recommendation widgets that appear on the sidebar when you visit them serve as a vector to promote similar communities.



The Stop Mandatory Vaccination page, for example, features links to "Pages Liked by This Page," which include "Rhode Islanders for Vaccine Choice," "National Vaccine Information Center" (which is verified by Facebook), and "Briar's Journey After HPV Vaccine Injury," which claims a young girl's health has deteriorated after getting an HPV vaccine.



Facebook will also be blocking anti-vax content from ads and removing ad targeting options like “vaccine controversies." If accounts continue to promote anti-vax misinformation via ads, the platform may disable them.

Facebook's crackdown on vaccination misinformation will also extend to Instagram. Anti-vax hashtags will no longer populate on Instagram hashtag pages, and they will be blocked from Instagram's explore tab.

Despite the popularity of anti-vaccination misinformation, the scientific consensus is that vaccines are safe and do not cause autism.

