TUESDAY, Sept. 6, 2022 (HealthDay News) -- The risk estimate for myocarditis in the 30 days after receipt of a COVID-19 booster dose (BNT162b2) is 1.42 per 100,000 overall, with higher risk seen in young males, according to a research letter published online Sept. 5 in Circulation.
Dror Mevorach, M.D., from Hadassah Medical Center in Jerusalem, Israel, and colleagues reviewed data for all cases of myocarditis from July 31, 2021 (first day of booster vaccination) through Nov. 5, 2021, regardless of vaccination status. During the surveillance period, 3,944,797 individuals (48.7 percent male) received a booster dose.
The researchers identified 91 cases of myocarditis, including 35 cases within 30 days of booster vaccination. Of these, 28 were probable or confirmed myocarditis, 18 of which occurred during the first week after the booster. All cases were mild clinically and patients recovered after a 3.5-day average hospitalization; no readmissions were seen during 90 days of follow-up. In the 30 days after the booster, risk estimates were 1.42 per 100,000 overall and 6.44 and 5.21 per 100,000 for males aged 16 to 19 and 20 to 24 years, respectively. For males, the overall risk difference was −2.72 per 100,000 compared with vaccine dose 2, which was mainly driven by males aged 16 to 19 years of age (−8.45). The overall risk difference was −0.48 for females.
"It is important to understand the connections between this rare heart condition and COVID-19 vaccines, so we can monitor the prevalence of myocarditis and pay extra attention to those who are most at risk," Mevorach said in a statement.