. 2021 Jun 29;6(10):1–5. doi: 10.1001/jamacardio.2021.2833

Table 3. Expected vs Observed Cases of Myocarditis in Military Health System Patients Based on Number of Messenger RNA (mRNA) COVID-19 Vaccine Doses Administered.

Doses of mRNA COVID-19 vaccine (through April 30, 2021)	No. of myocarditis cases
Doses of mRNA COVID-19 vaccine (through April 30, 2021)	Expected^a	Observed
2 810 000 Total doses	2 to 52	23
1 065 000 Second doses	1 to 20	20
544 000 Second doses to military members	0 to 10	19
436 000 Second doses to male military members	0 to 8	19

^{^a}

Expected number is based on an expected annual incidence ranging from 1 per 100 000 person-years to 22 per 100 000 person-years^5,6 presenting within a 30-day period after vaccination.