Abstract 11186: Clinical Presentation and Outcome of Myocarditis After Covid-19 Vaccination Among Adolescents: A Systematic Review and Meta-Analysis

Abstract

Introduction: The association of the COVID-19 vaccination with myocarditis has been reported in adolescents. However, evidence of myocarditis after COVID-19 vaccination among adolescents is scarce compared to adults. We aimed to investigate the clinical features and outcomes of COVID-19 mRNA vaccination-related myocarditis in adolescents. Methods: PubMed and EMBASE were searched through April 2022 to investigate the characteristics of vaccine-associated myocarditis in adolescent patients (aged 12-20 years) through observational studies, case series, and correspondence according to PRISMA guidelines. Data regarding patient characteristics, the type, and dose of the vaccine, laboratory data, imaging studies, mortality, and treatments were extracted from each article. One-group meta-analysis in a random-effects model was performed. Results: 22 observational studies were identified, including 861 cases of vaccine-associated myocarditis. The mean age was 16.0 (95%CI, 15.5-16.5), and the male was predominant at 90.8%. Three-quarters of myocarditis occurred after the second dose (78.2%, 95% CI, 62.4- 94.0). The incident rate was higher after the second dose (12.7 -118.7 per million persons) than the first dose (0.6-10.0 per million persons). Chest pain (85.2%) was the common presenting symptom. Although 16.0% of patients (51/302) had left ventricular (LV) systolic dysfunction (LV ejection fraction [EF] < 55%), most of the cases (40/289) were mildly reduced LVEF as 45-54% (12.0% of total patients). Interestingly, cardiac magnetic resonance imaging revealed late gadolinium enhancement in 80.5% (95% CI, 65.7-95.2) of the cases. Overall, 92.8% of patients required hospitalization, and 14.7% required intensive care unit admission. However, no in-hospital mortality was observed (0/230), and the length of stay at the hospital was less than 5 days. Conclusions: This systematic review and meta-analysis demonstrate a low incident rate and largely favorable outcomes of COVID-19 vaccine-associated myocarditis in adolescents. Our findings would help better understand myocarditis following COVID-19 mRNA vaccination among adolescents and decision-making for parents with vaccine hesitancy.