An association between Covid-19 vaccination and myocarditis has been previously reported.20 Although no cases of myocarditis were reported in the BNT162b2 (Pfizer–BioNTech),2 mRNA-1273 (Moderna),3 or ChAdOx1 nCoV-19 (AstraZeneca)4 phase 3 clinical trials, multiple cases of myocarditis after Covid-19 vaccination have recently been reported in the literature,21-25 and both the Israeli Ministry of Health26 and the CDC have investigated this association.27 The risk appears to be highest among young men.26,27 We found that the risk of myocarditis increased by a factor of three after vaccination, which translated to approximately 3 excess events per 100,000 persons; the 95% confidence interval indicated that values between 1 and 5 excess events per 100,000 persons were compatible with our data. Among the 21 persons with myocarditis in the vaccinated group, the median age was 25 years (interquartile range, 20 to 34), and 90.9% were male.