Myocarditis Following COVID-19 Vaccination: A Systematic Review

COVID-19 vaccination has significantly reduced both the morbidity and mortality rates associated with SARS-CoV-2 infection. Vaccines, especially mRNA vaccines, have been proposed in several studies to complicate viral myocarditis. Thus, our systematic and meta-analysis review aims to further investigate the possibility of an association between COVID-19 vaccines and myocarditis. We systematically searched PubMed, Web of Science, Scopus, Ovid, and Google Scholar and did a gray search of other databases using the following keywords and terms: "Myocarditis ("Myocarditis" Mesh) OR "Chagas Cardiomyopathy" Mesh) AND "COVID-19 Vaccines" Mesh. The studies were limited to only English articles that reported myocardial inflammation or myocarditis associated with COVID-19 vaccines. Pooled risk ratio with its 95% confidence interval was analyzed by RevMan software (5.4) to perform the meta-analysis. Our study included 671 patients from 44 studies with a mean age of 14-40 years. Nevertheless, myocarditis was noted in a mean of (3.227) days, and 4.19 per million vaccination recipients experienced myocarditis. Most cases were clinically presented with manifestations of cough, chest pain, and fever. Laboratory tests revealed increased C-reactive protein, and troponin with all other cardiac markers in most patients. Cardiac magnetic resonance imaging (MRI) revealed late gadolinium enhancement with myocardial edema and cardiomegaly. Also, electrocardiograms revealed ST-segment elevation in most patients. Furthermore, the incidence of myocarditis was statistically significantly lower in the COVID-19 vaccine group as compared with the control group (RR = 0.15, 95% CI = 0.10-0.23, p-value < 0.00001). No significant association was found between COVID-19 vaccines and the incidence of myocarditis. The study's findings highlight the importance of implementing evidence-based COVID-19 prevention strategies, such as vaccination, to reduce the public health impact of COVID-19 and its associated complications.