Age- and sex-stratified risks of myocarditis and pericarditis attributable to COVID-19 vaccination: A systematic review and meta-analysis

While COVID-19 vaccines are generally very safe, the risks of myocarditis and pericarditis has been established following mRNA vaccines, with the highest risk in young males. Most systematic reviews and meta-analyses of the risk of myocarditis or pericarditis have included passive surveillance data, which is subject to reporting errors. Accurate measures of age-, sex-, vaccine dose-, and vaccine type-specific risks are crucial for assessment of the benefits and risks of the vaccination. A systematic review and meta-analysis of the risks of myocarditis and pericarditis attributable COVID-19 vaccines was conducted stratified by age groups, sex, vaccine type, and vaccine dose. Five electronic databases and grey literature sources were searched on November 21, 2023.Studies that compared a COVID-19 vaccinated group with an unvaccinated group or time period (e.g., self-controlled) were included. Passive surveillance data were excluded. Meta-analyses were conducted using random-effects models. We identified 4,030 records and included 17 studies. Compared with unvaccinated groups or unvaccinated time periods, the highest attributable risk of myocarditis/pericarditis was observed after their 2nd dose in males aged 12-17 years (10.18 per 100,000 doses (95% confidence interval [CI] 0.50-19.87)) to BNT162b2 and in males aged 18-24 years (AR 20.02 per 100,000 doses (95% CI 10.47-29.57)) for mRNA-1273. The stratified results based on active surveillance data provide the most accurate available estimates of the risks of myocarditis and pericarditis attributable to specific COVID-19 vaccinations for specific populations.