Conspire to one's own detriment: Strengthening HPV Program Support Through Debunking Epistemically Suspect Beliefs.

The study experimentally tested an intervention that debunks epistemically suspect beliefs about vaccines. After answering questions about pre-existing epistemically suspect beliefs (irrational health beliefs and conspiracy mentality), 565 participants were randomly assigned into one of three conditions and exposed either to neutral information about domestic animals, salient epistemically suspect content about vaccination or an intervention that debunks epistemically suspect beliefs about vaccination. Afterwards, the participants answered questions about vaccination-related conspiracy narratives (manipulation check), vaccination attitudes, intentions to vaccinate against HPV, support for an HPV vaccination programme and intentions to seek health guidance. Although the intervention demonstrated the potential to inhibit the endorsement of conspiracy narratives, we found no differences in the other outcome variables. Nevertheless, across the conditions, pre-existing epistemically suspect beliefs were associated with less favourable attitudes towards vaccination, lower intentions to vaccinate against HPV, less support for the vaccination programme and lower intentions to seek health guidance. The results indicate that debunking may be futile in curbing long-term negative impacts associated with epistemically suspect beliefs, and they contribute to the debate about assessing the effectiveness of interventions related to highly controversial topics such as vaccination. The study enhances understanding of persistent adverse impacts that epistemically suspect beliefs may have on public health outcomes.