Vaccine hesitancy is associated with overuse of antibiotics: From paradox to pattern

Vaccine hesitancy and antibiotic overuse are major global health threats, yet they are typically treated as separate problems, stemming from different sets of causes. In this study, we challenge this 'different causes–different problems' assumption by testing two contrasting models of how vaccines and antibiotic behaviors might be related psychologically.In one view, they could reflect a common stable attitude. People who distrust biomedical treatments or have a preference for natural immunity might avoid both vaccines and antibiotics. If so, one should observe individuals being vaccine hesitant or overusing antibiotics, but not both.An alternative view, grounded in cognitive neuroscience, posits a single state-dependent mechanism that prioritizes action when ill but inaction when healthy. This yields the somewhat-counterintuitive prediction that the same people who avoid vaccines would also overuse antibiotics.Across four countries (USA, UK, France and Argentina; N=1,307), our survey results support the second, state-dependent pattern: Across diverse healthcare contexts, individuals more hesitant about vaccines were also more likely to overuse antibiotics.This asymmetry calls for a rethinking of public health strategies to address vaccination and antibiotic use together, rather than in isolation, and in a way that is sensitive to target audiences' health states.