Just two organizations were responsible for the majority of anti-vaccine advertisements on Facebook before the social media giant restricted such content in March of this year, according to a November 13 study in the journal Vaccine.
Of 145 anti-vaccine Facebook advertisements that ran between May 31, 2017 and February 22, 2019, the World Mercury Project and a group called Stop Mandatory Vaccination together ran 54% of them.
The World Mercury Project, which ran the most ads of any single source, is an organization closely aligned with the anti-vaccine group Children’s Health Defense. Both are spearheaded by Robert F. Kennedy Jr., an environmental lawyer turned prolific peddler of dangerous anti-vaccine misinformation. He and his organizations promote conspiracy theories about vaccine safety, including the roundly debunked claim that safe, life-saving immunizations are linked to autism. More recently, Kennedy has become a prominent opponent of laws aimed at increasing vaccination rates among school children.