Perceived experts are prevalent and influential within an antivaccine community on Twitter.

Perceived experts (i.e. medical professionals and biomedical scientists) are trusted sources of medical information who are especially effective at encouraging vaccine uptake.

The role and influence of perceived experts in an anti-vaccine misinformation community.

The role of perceived experts (i.e., medical professionals and biomedical scientists) as potential anti-vaccine influencers has not been characterized systematically.