Myocarditis Post Moderna Vaccination: Review of Criteria for Diagnosis

Case reports of myocarditis post-coronavirus disease 2019 (COVID-19) mRNA vaccination have not uniformly reported long-term follow-up beyond 90 days. We present a 23-year-old male who is typical of a patient presenting with myocarditis post-COVID-19 mRNA-1273 Moderna vaccination (young males, onset several days after second dose of the mRNA vaccine, and excellent short term complete recovery). Follow-up at 128 days revealed no residual sequelae in our patient. Although a definitive diagnosis of myocarditis requires an endomyocardial biopsy (EMB), diagnosis is usually made clinically and with imaging in most clinical settings unless part of an approved research protocol or if indicated clinically. We recommend active surveillance and reporting for myocarditis post mRNA vaccination and even consider reporting those with symptom onset beyond 90 days.