evidence: While mRNA COVID-19 vaccines like tozinameran (Pfizer-BioNTech BNT162b2) and elasomeran (Moderna mRNA-1273) have shown a high level of efficacy and effectiveness in real life, some concerns about vaccination-related pericarditis and/or myocarditis have been raised.1,2 After the initial signals from Israel, the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) alerted on the risk of pericarditis and/or myocarditis with mRNA COVID-19 vaccines.2,3 In August 2021, the US Centers for Disease Control and Prevention (CDC) published data suggesting a higher rate of vaccination-related myocarditis in young men, but no stratification was made on the adolescent age group.4 Recently, two observational studies from Israel estimated the incidence of myocarditis to be around 0.64 and 1.42 per 100 000 persons after the first dose of tozinameran and 3.83 per 100 000 after the second dose.5,6 The risk difference between the first and second doses of tozinameran was evaluated to be 1.76 per 100 000 persons, with a great difference among boys between 16 and 19 years of age.6 To date, no data have been published on young adolescents between 12 and 15 years of age.