Who is perceived to be an expert on COVID-19 vaccines on social media?: Biomedical credentials confer expertise, even among vaccine-hesitant and Conservative observers.

Who is perceived to be an expert on COVID-19 vaccination on social media? We conducted four experimental studies investigating how the presence of biomedical credentials in social media profiles impacts users' perceived expertise. Participants viewed a series of Twitter profiles that appeared with or without biomedical credentials and judged to what extent they believed each user was an expert on the topic of COVID-19 vaccination. We found that the presence of biomedical credentials consistently increased perceptions of expertise, including among unvaccinated, vaccine-hesitant, and conservative participants. In some cases, participants who were less vaccine-hesitant, had been vaccinated, and identified as more liberal were generally more influenced by the presence of credentials when judging COVID-19 vaccination expertise; however, credentials still had a significant and large effect regardless of vaccination status and attitude or political partisanship, and was much larger than the effect of any moderators. These findings support existing observations that biomedical credentials may be leveraged by both pro- and anti-vaccine communities to increase perceived credibility and message reach, and counter the narrative that conservatives and those with anti-vaccination attitudes do not recognize biomedical credentials as conferring expertise.