Myocarditis following COVID-19 mRNA vaccination

Messenger RNA vaccines are the main COVID-19 vaccines authorized for use in the United States. Side effects are typically minor and transient. We report a case series of four subjects with an acute myocarditis-like illness following mRNA COVID-19 vaccination who were hospitalized at our hospital in Lubbock, Texas. Three patients were young men who presented with acute chest pain after the second dose of the mRNA-1273 vaccine. Another patient was a 53-year-old white woman who presented with acute left arm pain 3 days after the first dose of the mRNA-1273 vaccine. She was later found to have acute decompensated heart failure, and endomyocardial biopsy revealed eosinophilic injury–mediated myocarditis.