Abstract
OBJECTIVE: Negative beliefs about medication and vaccine side-effects can spread rapidly through social communication. This has been recently documented with the potential side-effects from the COVID-19 vaccines. We tested if pre-vaccination social communications about side-effects from personal acquaintances, news reports, and social media predict post-vaccination side-effect experiences. Further, as previous research suggests that side-effects can be exacerbated by negative expectations, we assessed if personal expectations mediate the relationships between social communication and side-effect experience. METHOD: In a prospective longitudinal survey (N = 551), COVID-19 vaccine side-effect information from three sources-social media posts, news reports, and first-hand accounts from personal acquaintances-as well as side-effect expectations, were self-reported pre-vaccination. Vaccination side-effect experience was assessed post-vaccination. RESULTS: In multivariate regression analyses, the number of pre-vaccination social media post views (β = 0.17) and impressions of severity conveyed from personal acquaintances (β = 0.42) significantly predicted an increase in pre-vaccination side-effect expectations, and the same variables (βs = 0.11, 0.14, respectively) predicted post-vaccination side-effect experiences. Moreover, pre-vaccination side-effect expectations mediated the relationship between both sources of social communication and experienced side-effects from a COVID-19 vaccination. CONCLUSIONS: This study identifies links between personal acquaintance and social media communications and vaccine side-effect experiences and provides evidence that pre-vaccination expectations account for these relationships. The results suggest that modifying side-effect expectations through these channels may change the side-effects following a COVID-19 vaccination as well as other publicly discussed vaccinations and medications.