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

J Emerg Med. 2021 Dec;61(6):e129-e132. doi: 10.1016/j.jemermed.2021.09.017. Epub 2021 Sep 27.


Background: In May 2021, the U.S. Food and Drug Administration expanded the Emergency Use Authorization for the Pfizer-BioNTech mRNA Coronavirus disease 2019 (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.

Case report: This case report describes a 17-year-old male patient 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 electrocardiographic changes consistent with a STEMI. 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.

Keywords: BNT162b2; COVID-19; STEMI; mRNA vaccine; myocarditis.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • BNT162 Vaccine
  • COVID-19 Vaccines
  • COVID-19*
  • Humans
  • Male
  • Myocarditis* / diagnosis
  • RNA, Messenger
  • SARS-CoV-2
  • ST Elevation Myocardial Infarction* / diagnosis


  • COVID-19 Vaccines
  • RNA, Messenger
  • BNT162 Vaccine