Table 2:

Expected and observed rates of myocarditis with observed-to-expected ratios within a 7-day risk window after SARS-CoV-2 vaccination

Variable	Observed^*			Expected^†			OE ratio (95% CI)

	No. of cases	No. of vaccine doses	Rate per 100 000 (95% CI)	No. of cases	Population	Rate per 100 000 (95% CI)
Overall	99	10 255 385	0.97 (0.78–1.17)	6.7	5 090 955	0.13 (0.06–0.28)	14.81 (10.83–16.55)

Sex

Male	80	4 891 011	1.64 (1.30–2.04)	2.4	2 571 779	0.09 (0.02–0.34)	33.74 (26.76–42.00)

Female	19	5 364 374	0.35 (0.21–0.55)	4.4	2 519 176	0.18 (0.06–0.46)	4.31 (2.59–6.73)

Age, yr

12–17	17	644 705	2.64 (1.54–4.22)	0.2	300 573	0.08 (0.01–1.85)	68.88 (40.12–110.28)

18–29	47	1 784 950	2.63 (1.94–3.50)	1.8	822 028	0.22 (0.03–0.88)	26.25 (19.29–34.90)

30–39	14	1 624 133	0.86 (0.47–1.45)	1.5	721 055	0.21 (0.03–1.00)	9.26 (5.06–15.54)

40–49	4	1 340 746	0.30 (0.08–0.76)	0.9	647 731	0.13 (0.00–0.86)	4.58 (1.25–11.73)

50–59	5	1 420 691	0.35 (0.11–0.82)	0.8	725 412	0.10 (0.00–0.77)	6.66 (2.16–15.53)

60–69	6	1 552 275	0.39 (0.14–0.84)	0.8	660 685	0.12 (0.00–0.84)	7.83 (2.87–17.05)

70–79	3	1 228 162	0.24 (0.05–0.71)	1.1	413 888	0.26 (0.06–1.75)	2.77 (0.57–8.11)

≥ 80	3	659 723	0.45 (0.09–1.33)	0.3	229 260	0.14 (0.01–2.43)	9.06 (1.87–26.48)

Vaccine

Pfizer	52	6 989 921	0.74 (0.56–0.98)	4.6	5 090 955	0.09 (0.03–0.23)	11.42 (8.53–14.97)

Moderna	47	3 265 464	1.44 (1.06–1.91)	2.1	5 090 955	0.04 (0.00–0.14)	22.09 (16.23–29.37)

Dose

Dose 1	7	3 994 380	0.18 (0.07–0.36)	2.6	5 090 955	0.05 (0.01–0.17)	2.69 (1.08–5.54)

Dose 2	74	3 884 987	1.90 (1.50–2.39)	2.5	5 090 955	0.05 (0.01–0.17)	29.23 (22.95–36.69)

Dose 3	18	2 376 018	0.76 (0.45–1.20)	1.5	5 090 955	0.03 (0.00–0.14)	11.62 (6.89–18.37)

Note: CI = confidence interval, Moderna = mRNA-1273 (Moderna), OE = observed-to-expected, Pfizer = BNT162b2 (Pfizer-BioNTech).
↵* Myocarditis cases recorded within 7 days postvaccination between Dec. 15, 2020, and Mar. 31, 2022.
↵† The background rates from 2019 were used to calculate the expected numbers.