Medical authority on anti-vaccine WhatsApp groups in Brazil

In this article, we analyze how medical authority is used in the production and legitimization of anti-vaccine opinions in Brazilian WhatsApp groups, from July 20, 2022 to July 31, 2023 by searching for descriptors related to the topic of vaccines, which led to the identification of five anti-vaccine groups in this application. Using grounded theory methodology, we conducted an analysis of the key tactical and discursive articulations around healthcare professionals, reflected in 945 messages shared in these groups. In this analysis, we found that medical authority is primarily used to support opinions against the safety and efficacity of vaccines, to glorify anti-vaccination doctors and to oppose physicians with positions other than those of the antivaccination movement. The analysis thus shows that these groups maintain a dubious relationship with medical authority, which is challenged in the process of forming and consolidating the beliefs and opinions on health shared there. In this context, we observed that users perceive the antivaccination groups studied here as safe spaces for finding and recommending doctors who share antivaccination views, reinforcing the scenario of misinformation based on medical authority in the contemporary era.