Overview of SARS-CoV-2 infection and vaccine associated myocarditis compared to non-COVID-19-associated myocarditis: A systematic review and meta-analysis

Abstract

BackgroundPrevious literature suggests that both SARS-CoV-2 infection and COVID-19 mRNA vaccine are associated with myocarditis, in which the incidence is higher in the infection group. COVID-19 mRNA vaccine-related myocarditis is noted to have a more benign course. Despite these findings, there is a need for a larger population systematic review that compares the outcomes to pre-pandemic acute myocarditis to better understand the extent of the current post-COVID state. MethodsWe performed a literature search with PubMed and EMBASE and identified studies investigating COVID-19 and its vaccinated population, and the population prior to the pandemic (control group) who had myocarditis. We performed a one-group meta-analysis of the incidence, baseline demographics, and outcomes of myocarditis for each group. ResultsThe incidence in the SARS-CoV-2 infection group was 2.76 per thousand (95% CI, 0.85–8.92), 19.7 per million (95% CI, 12.3–31.6) in the vaccine group, and 0.861 per million (95% CI, 0.04–16.7) in the control group. The majority of patients were male, with the highest proportion in the vaccine group. The mean age was the youngest in the vaccine group (24.8, 95% CI, 19.1–30.6). The vaccine group had the lowest mortality (2.0%, 95% CI, 1.3–2.7) followed by the control and the SARS-CoV-2 infection group. The vaccine group had the lowest proportion of immunoglobulin and glucocorticoid use, mechanical circulatory support, and cardiogenic shock. ConclusionOur study showed favorable outcomes of myocarditis in patients with COVID-19 mRNA vaccination, despite a higher incidence than pre-COVID controls. Further studies with standardized myocarditis diagnostic criteria assessing long-term outcomes are necessary.