The incidence of myocarditis and pericarditis has been documented in adolescents after COVID-19 vaccinations. This study aims to assess the risk of myopericarditis in adolescents following COVID-19 vaccination, using a meta-analysis of the published cases. We performed a comprehensive literature search of the following databases on July 5, 2023: MEDLINE, EMBASE, PubMed, and the Cochrane Library. We performed a meta-analysis using a random-effects model to estimate the incidence of myopericarditis per million of administered COVID-19 vaccine doses or COVID-19 infections. A total of 33 studies were included in the meta-analysis. The incidence of myopericarditis per million COVID-19 infections (1583.9 cases, 95% CI 751.8–2713.8) was approximately 42 times higher than that for COVID-19 vaccine administrations (37.6 cases, 95% CI 24.2–53.8). The risk of myopericarditis after COVID-19 vaccination was particularly high among the 16–19 age group (39.5 cases per million, 95% CI 25.8–56.0), males (43.1 cases per million, 95% CI 21.6–71.9), and those who received the second dose (47.7 cases per million, 95% CI 22.2–82.2). There were no significant differences in the incidence of myopericarditis per million COVID-19 vaccine administrations between Europe, the Western Pacific, and the Americas (p = 0.51). Adolescents faced a potential risk of myopericarditis after COVID-19 vaccination, but this risk is less harmful than that of myopericarditis following COVID-19 infection.
Following the start of the COVID-19 vaccination campaign, the adverse events of myocarditis and pericarditis were linked mainly to mRNA COVID-19 vaccines by the regulatory authorities worldwide. COVID-19 vaccines have been administered to several million people and the risk of myocarditis post COVID-19 vaccination has been characterised in great detail. At the present time the research data available are scarce and there is still no clear understanding of the biological mechanism/s responsible for this disease. This manuscript provides a concise overview of the epidemiology of myocarditis and the most prominent mechanistic insights in the pathophysiology of the disease. Most importantly it underscores the needed next steps in the research agenda required to characterize the pathophysiology of this disease post-COVID-19 vaccination. Finally, it shares our perspectives and considerations for public health.