Myocarditis after Covid-19 Vaccination in a Large Health Care Organization

This retrospective cohort study evaluated myocarditis incidence following administration of the BNT162b2 mRNA Covid-19 vaccine within Israel’s largest healthcare organization. Of 2.56 million vaccinated individuals aged 16 or older, 54 developed myocarditis meeting CDC criteria—yielding an estimated incidence of 2.13 cases per 100,000. Rates were highest among males aged 16–29 (10.69 per 100,000). Most cases were mild or intermediate; one patient developed cardiogenic shock and another died of unknown causes post-discharge. Left ventricular dysfunction occurred in 29% at presentation, with normal function restored in most cases with follow-up. The findings confirm a low but measurable myocarditis risk post-vaccination, concentrated among young males.

This retrospective cohort study evaluated myocarditis incidence following administration of the BNT162b2 mRNA Covid-19 vaccine within Israel’s largest healthcare organization. Of 2.56 million vaccinated individuals aged 16 or older, 54 developed myocarditis meeting CDC criteria—yielding an estimated incidence of 2.13 cases per 100,000. Rates were highest among males aged 16–29 (10.69 per 100,000). Most cases were mild or intermediate; one patient developed cardiogenic shock and another died of unknown causes post-discharge. Left ventricular dysfunction occurred in 29% at presentation, with normal function restored in most cases with follow-up. The findings confirm a low but measurable myocarditis risk post-vaccination, concentrated among young males.