Myopericarditis following COVID-19 vaccination in children: a systematic review and meta-analysis

INTRODUCTION: Myopericarditis is a rare but serious coronavirus disease 2019 (COVID-19) vaccine-related adverse event primarily affecting adolescents. Given recent approvals for childhood vaccination, we performed a meta-analysis investigating myopericarditis following messenger ribonucleic acid COVID-19 vaccination in children aged <19 years, focusing on its overall risk and high-risk subgroups. METHODS: We searched MEDLINE via PubMed, Embase and Scopus from inception to 1 August 2022 for observational studies reporting myopericarditis in temporal relation to paediatric COVID-19 vaccination. We conducted random-effects meta-analyses (DerSimonian and Laird) on myopericarditis (primary outcome), myocarditis and pericarditis (secondary outcomes). RESULTS: Of 2115 studies, 12 (59,229,160 doses) studies were included in our analysis. There were 19.8 (95% confidence interval CI: 10.4-37.6) myopericarditis cases reported per million doses in children, compared to 23.7 (95% CI: 12.2-46.1) cases in adults (eight studies, 376,899,888 doses; P = 0.70). Compared to the second dose (34.4, 95% CI: 15.2-77.8), the number of cases post-first dose was significantly lower (9.1, 95% CI: 4.4-18.8; P = 0.017), while the number of cases post-third dose was not higher than that of post-second dose (28.4, 95% CI: 10.4-61.8; P = 0.57, global P = 0.031). Males were at higher risk of myopericarditis (67.4, 95% CI: 36.5-124.5) than females (6.9, 95% CI: 3.1-15.3; P < 0.0001). Finally, the number of cases was higher (overall P < 0.0001) among children aged ≥12 years (39.9, 95% CI: 24.1-66.0) than among children aged <12 years (3.0, 95% CI: 2.3-3.9). CONCLUSION: Our meta-analysis showed 19.8 cases of myopericarditis per million doses among children, not significantly different from that of adults. Higher risk subgroups included adolescents, males, and those receiving their second dose of vaccination.