Myocarditis is now recognized as a rare complication of coronavirus disease 2019(COVID-19)mRNA vaccination,particularly in adolescent and young adult males.Since the authorization of the Pfizer-BioNTech^(TM)and Moderna^(TM)mRNA vaccines targeting the severe acute respiratory syndrome coronavirus-2(SARSCoV-2)spike protein,the Centers for Disease Control and Prevention(CDC)has reported 1175 confirmed cases of myocarditis after COVID-19 vaccination in individuals ages 30 years and younger as of January 2022.According to CDC data in June 2021,the incidence of vaccine-mediated myocarditis in males ages 12-29 years old was estimated to be 40.6 cases per million second doses of COVID-19 mRNA vaccination administered.Individuals with cases of COVID-19 vaccinemediated myocarditis typically present with acute chest pain and elevated serum troponin levels,often within one week of receiving the second dose of mRNA COVID-19 vaccination.Most cases follow a benign clinical course with prompt resolution of symptoms.Proposed mechanisms of COVID-19 vaccine myocarditis include molecular mimicry between SARS-CoV-2 spike protein and self-antigens and the triggering of preexisting dysregulated immune pathways in predisposed individuals.The higher incidence of COVID-19 vaccine myocarditis in young males may be explained by testosterone and its role in modulating the immune response in myocarditis.There is limited data on long-term outcomes in these cases given the recency of their occurrence.The CDC continues to recommend COVID-19 vaccination for everyone 5 years of age and older given the greater risk of serious complications related to natural COVID-19 infection including hospitalization,multisystem organ dysfunction,and death.Further study is needed to better understand the immunopathology and long-term outcomes behind COVID-19 mRNA vaccine-mediated myocarditis.
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