Comirnaty vaccination in adolescents was associated with an overall acute myocarditis/pericarditis incidence of 18.52 per 100,000 persons, representing a significant increase compared to the background rate.
Cohort (n=178,163)
Yes
Does Comirnaty vaccination increase the risk of acute myocarditis/pericarditis in adolescents aged 12-17 years?
Comirnaty vaccination in adolescents is associated with a significantly increased risk of mild acute myocarditis/pericarditis, particularly in males following the second dose.
Effect estimate: Incidence rate difference 18.41 per 100,000 person-14 days (95% CI 9.95-26.87)
Absolute Event Rate: 18.52% vs 0.11%
p-value: p=<0.05
BACKGROUND: Age-specific incidence of acute myocarditis/pericarditis in adolescents following Comirnaty vaccination in Asia is lacking. This study aimed to study the clinical characteristics and incidence of acute myocarditis/pericarditis among Hong Kong adolescents following Comirnaty vaccination. METHODS: This is a population cohort study in Hong Kong that monitored adverse events following immunization through a pharmacovigilance system for coronavirus disease 2019 (COVID-19) vaccines. All adolescents aged between 12 and 17 years following Comirnaty vaccination were monitored under the COVID-19 vaccine adverse event response and evaluation program. The clinical characteristics and overall incidence of acute myocarditis/pericarditis in adolescents following Comirnaty vaccination were analyzed. RESULTS: Between 14 June 2021 and 4 September 2021, 33 Chinese adolescents who developed acute myocarditis/pericarditis following Comirnaty vaccination were identified. In total, 29 (87.88%) were male and 4 (12.12%) were female, with a median age of 15.25 years. And 27 (81.82%) and 6 (18.18%) cases developed acute myocarditis/pericarditis after receiving the second and first dose, respectively. All cases are mild and required only conservative management. The overall incidence of acute myocarditis/pericarditis was 18.52 (95% confidence interval CI, 11.67-29.01) per 100 000 persons vaccinated. The incidence after the first and second doses were 3.37 (95% CI, 1.12-9.51) and 21.22 (95% CI, 13.78-32.28 per 100 000 persons vaccinated, respectively. Among male adolescents, the incidence after the first and second doses were 5.57 (95% CI, 2.38-12.53) and 37.32 (95% CI, 26.98-51.25) per 100 000 persons vaccinated. CONCLUSIONS: There is a significant increase in the risk of acute myocarditis/pericarditis following Comirnaty vaccination among Chinese male adolescents, especially after the second dose.
Chua et al. (2021) conducted a cohort in Acute myocarditis/pericarditis (n=178,163). Comirnaty vaccination vs. Background incidence rate in 2020 was evaluated on Incidence of acute myocarditis/pericarditis per 100,000 persons (Incidence rate difference 18.41 per 100,000 person-14 days, 95% CI 9.95-26.87, p=<0.05). Comirnaty vaccination in adolescents was associated with an overall acute myocarditis/pericarditis incidence of 18.52 per 100,000 persons, representing a significant increase compared to the background rate.