Side-effect expectations from COVID-19 vaccination: findings from a nationally representative cross-sectional survey (CoVAccS – wave 2)

Objectives: Concern about side effects is one of the most common reasons for refusing vaccination. Side-effect expectations are also known to predict perception of side effects. We aimed to investigate the percentage of people who thought side effects from COVID-19 vaccination were likely and investigate factors associated with side-effect expectation. Methods: Online cross-sectional survey of 1470 UK adults who had not been vaccinated for COVID-19 (conducted 13 to 15 January 2021). We asked participants how likely they thought side effects from COVID-19 vaccination were. Linear regression analyses were used to investigate associations with side-effect expectations. Results: Most participants were uncertain whether they would experience side effects from a COVID-19 vaccine; only a minority reported that side effects were very likely (9.4%, 95% CI 7.9% to 10.9%, n=138/1470). Personal and clinical characteristics, general, and COVID-19 vaccination beliefs and attitudes explained 29.7% of the variance in side-effect expectation, with COVID-19 vaccination beliefs alone accounting for 17.2%. Side-effect expectations were associated with: older age, being clinically extremely vulnerable to COVID-19, being afraid of needles, lower perceived social norms for COVID-19 vaccination, lower perceived necessity and safety of COVID-19 vaccination, and perceived lack of information about COVID-19 and vaccination. Conclusions: Side-effect expectation was associated with believing that COVID-19 vaccination was unsafe, ineffective and that others would be less likely to approve of you having a COVID-19 vaccination. Communications should emphasise the safety, effectiveness, and widespread uptake of vaccination, while promoting accurate perceptions of the incidence of vaccination side effects