Abstract
Myocarditis has been described previously as a rare side effect of both influenza and smallpox vaccines. In this report, we present a case of acute perimyocarditis in a young, healthy man after vaccination with the mRNA-1273 severe acute respiratory syndrome coronavirus -2 (SARS-CoV-2; Moderna) vaccine. He presented with chest pain and decompensated heart failure 3 days after administration of his second dose, and his symptoms resolved by 9 days post-inoculation. This case highlights a rare but potentially serious side effect of this mRNA vaccine that primary care physicians and cardiologists should be aware of in order to identify and appropriately manage these patients.