Conspiracy beliefs explain why intolerance of uncertainty, personal control, and political uncontrollability predict willingness to get vaccinated against COVID-19.

Conspiracy theories tend to be disseminated in times when anxiety and uncertainty prevail. Thus, the outbreak of the COVID-19 pandemic was fertile ground for the dissemination of conspiracy theories. The current study examined the role of conspiracy belief in the association between individual differences in perceptions of lack of control and certainty, and willingness to get vaccinated against COVID-19. Participants ( N  = 323) completed measures of willingness to get vaccinated, belief in COVID-19 vaccines conspiracy, intolerance of uncertainty (IOU), perceived personal control, and political uncontrollability. Results show that conspiracy beliefs mediated the positive association between perceived personal control and willingness to get vaccinated, and the negative association between political uncontrollability and willingness to get vaccinated. Additionally, conspiracy belief had a suppression effect on the association between IOU and willingness to get vaccinated. These findings indicate that uncertainty and sense of lack of control heighten the need for an explanation that offers some degree of clarity, which in turn is related to adoption of conspiracy theories and may consequently have negative effects on health behavior.