evidence: Large-scale COVID-19 vaccination using mRNA technology revealed a small but real risk of vaccine-associated myocarditis (VAM). Presenting at rates of less than 4 per 100,000 in the general population, the incidence of VAM was too small to be detected in the vaccine safety and efficacy trials. Large-scale epidemiological and adverse event studies, conducted in multiple countries and using a variety of methodological approaches, have better characterized this risk according to vaccine type and subpopulation. Of particular note, VAM is most common among adolescent and young males between the ages of 12 and 24 years, with rates as high as 10.7 per 100,000. The clinical course of VAM is generally mild in both pediatric and adult populations. [...] References - Patone M, Mei XW, Handunnetthi L, et al. Risk of myocarditis following sequential COVID-19 vaccinations by age and sex. medRxiv. Published online December 25, 2021. doi:10.1101/2021.12.23.21268276.