STEMI Mimic - Focal Myocarditis in an Adolescent Patient After mRNA COVID-19 Vaccine

Azir, Michael; Inman, Brannon; Webb, James; Tannenbaum, Lloyd

Background In May 2021, the FDA expanded the emergency use authorization for the Pfizer-BioNTech mRNA COVID-19 Vaccine (BNT162b2) to include adolescents 12-15 years of age. As vaccine administration continues to increase, potential adverse outcomes to include myocarditis are being reported to the Vaccine Adverse Event Reporting System (VAERS). Case Report This case report describes a 17 year old male who developed focal myocarditis mimicking an ST-Segment Elevation Myocardial Infarction (STEMI) 3 days after administration of an mRNA COVID-19 vaccine. Why should an emergency physician be aware of this? Myocarditis is a rare complication in adolescents receiving mRNA COVID-19 vaccines. Focal myocarditis may demonstrate localizing ECG changes consistent with a ST-Segment Elevation Myocardial Infarction. Overall, complications of the mRNA COVID-19 vaccines are extremely rare. The vaccine continues to be recommended by public health experts, as the benefits of vaccinations greatly outweigh the rare side effects.