Social media use and expectations predict COVID-19 vaccine side effects: a prospective longitudinal study

Social media use has been implicated in the development of anti-vaccine attitudes. However, its connection with the post-vaccination experience itself remains unclear. The present longitudinal study examined how expectations and psychosocial factors are associated with the relationship between exposure to reports of COVID-19 vaccine side effects on social media and observers' post-vaccination side effect experience.

Prospective longitudinal study using online surveys.

Five hundred thirty-eight adults residing in Australia indicated the burden (i.e., number of symptoms and related severity) of COVID-19 vaccine side effects seen reported by other users on social media and their own expectations of experiencing post-vaccination side effects (T1). Perceptions of social media and psychosocial beliefs were also measured. Experience of vaccine-attributed side effects were self-reported after participants received their first (T2; n = 299) and second (T3; n = 155) vaccine doses.

There was a significant positive association between social media side effect burden exposure and the side effect burden experienced after receiving the first dose. Pre-vaccination side effect expectations formed an indirect association between these variables, but not for the exposure-second dose association. Worry about COVID-19 vaccine side effects, greater side effect severity experienced by known others, and stronger vaccine misconceptions strengthened the first dose indirect association through expectations.

Exposure to user-posted health information on social media was positively associated with post-vaccination side effect experiences and the pre-vaccination expectations associated with this relationship were modulated by several psychosocial factors. Health interventions should consider the potential role of social media-derived symptom information on negative health outcomes.