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

Although COVID-19 vaccines are generally very safe, the risks of myocarditis and pericarditis after receiving an messenger RNA (mRNA) vaccine have been established, with the highest risk in young men. 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-, and vaccine dose- and 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 were conducted, stratified by age groups, sex, vaccine type, and vaccine dose. Five electronic databases and gray literature sources were searched on November 21, 2023. Article about studies that compared a COVID-19-vaccinated group with an unvaccinated group or time period (eg, self-controlled) were included. Passive surveillance data were excluded. Meta-analyses were conducted using random-effects models. A total of 4030 records were identified; ultimately, 17 articles were included in this review. Compared with unvaccinated groups or unvaccinated time periods, the highest attributable risk of myocarditis or pericarditis was observed after the second dose in boys aged 12-17 years (10.18 per 100 000 doses [95% CI, 0.50-19.87]) of the BNT162b2 vaccine and in young men aged 18-24 years (attributable risk, 20.02 per 100 000 doses [95% CI, 10.47-29.57]) for the mRNA-1273 vaccine. 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. Trial registration: International Prospective Register of Systematic Reviews (PROSPERO) Identifier: CRD42023443343.