evidence: The rapid development and emergency approval of mRNA-based vaccines have proven instrumental in reducing disease severity and mortality from SARS-CoV-2 infection. The vaccines consist of liposomally protected mRNA transcripts that encode the SARS-Cov-2 spike protein — the protein that mediates entry of the virus into host cells via the receptor ACE2 (angiotensin-converting enzyme 2). In rare cases (about 2 per 100,000), people develop myocarditis after vaccination; the frequency is relatively higher in young male patients. Previous studies have hypothesized that this may be due to an excessive immune response in genetically predisposed participants; the effect of hormones — specifically testosterone — in altering T cell immune response; or potential molecular mimicry between spike protein and endogenous antigens that elicits cardiac-targeted autoantibodies. However, the immunopathological causes of myocarditis after COVID-19 vaccination remain unclear.