ABSTRACT
Background: Although rare, there is increasing incidence of myocarditis in young adult males who receive the second dose of the COVID-19 mRNA vaccine. We present a rare case of myocarditis in a young female following the initial dose. Case: A 20-year-old female presented with progressive pleuritic chest pain and fever. Past medical history was significant for depression and COVID-19 infection 5 months prior to admission. She received the first dose of the Moderna mRNA vaccine one week prior to admission. She had elevated D-dimer, erythrocyte sedimentation rate (ESR), and troponin levels. Electrocardiogram showed PR depression. Echocardiogram, respiratory viral panels, and cultures were normal. Decision-making: Due to persistent worsening chest pain, she underwent cardiac magnetic resonance imaging (CMRI), which was consistent with myocarditis. She was treated with supportive care and her condition improved. Given the temporal relationship between vaccine administration and symptom onset, as well as negative viral testing, it was determined that the Moderna vaccine was likely the culprit. Conclusion: COVID-19 vaccine-induced myocarditis is becoming a more recognized entity, however other more common etiologies should be first ruled out. Nonetheless, the benefits of immunization against COVID-19 outweigh the risks of vaccine-induced myocarditis. [Formula presented]