Self-reported real-world safety and reactogenicity of COVID-19 vaccines: An international vaccine-recipient survey

BackgroundThe safety of COVID-19 vaccines has been demonstrated in selected populations in recent studies, but more data in specific groups is needed to inform vaccine choice and health policy.ObjectivesAn international, online survey was conducted to compare the safety, tolerability and reactogenicity of available COVID-19 vaccines in different recipient groups.MethodsThis survey was launched in February 2021, for 11 days. Recipients of a first COVID-19 vaccine dose ≥7 days prior to survey completion were eligible. The incidence and severity of vaccination side effects were assessed.ResultsSurvey was completed by 2,002 respondents, of whom 26.6% had prior COVID-19 infection (68.8% laboratory confirmed). Prior COVID-19 infection was associated with increased risk of any side effect (risk ratio 1.08, 95% confidence intervals [1.05-1.11]), fever (2.24 [1.86-2.70]), breathlessness (2.05 [1.28-3.29]), flu-like illness (1.78 [1.51-2.10]), fatigue (1.34 [1.20-1.49]) and local reactions (1.10 [1.06-1.15]). It was also associated with increased risk of severe side effects, leading to hospital care (1.56 [1.14-2.12]).While mRNA vaccines were associated with a higher incidence of any side effect (1.06 [1.01-1.11]) compared to viral vector-based vaccines, these were generally milder (pConclusionFor the first time, our study links prior COVID-19 illness with increased incidence of vaccination side effects and demonstrates that mRNA vaccines cause milder, less frequent systemic side effects, but more local reactions.Key messages–People with prior COVID-19 illness appear to experience significantly increased incidence and severity of side effects after receiving the COVID-19 vaccine.–In this first head-to-head comparison of the safety and reactogenicity of different types of vaccines, it was demonstrated that mRNA vaccines cause milder, less frequent systemic side effects, compared to viral vector vaccines, but more local reactions.Tweetable SummaryA survey of >2000 COVID-19 vaccine-recipients links prior COVID-19 illness with increased incidence of vaccination side effects; mRNA vaccines cause milder, less frequent systemic side effects, but more local reactions.