Kim HW, Jenista ER, Wendell DC, et al. - The possibility of a link between messenger RNA (mRNA) COVID-19 vaccination and acute myocarditis is indicated by the results of this study but causality cannot be established. On magnetic resonance imaging, findings were consistent with acute myocarditis in 7 patients; 4 of whom had preceding COVID-19 vaccination.

• It is not known if COVID-19 vaccination may be associated with myocarditis development.

• This analysis involved 7 patients with acute myocarditis, 4 of whom occurred within 5 days of COVID-19 vaccination between February 1 and April 30, 2021.

• The second dose of a mRNA vaccine had been received by all 4 patients (2 received mRNA-1273 [Moderna], and 2 received BNT162b2 [Pfizer]).

• Presentation with severe chest pain, presence of biomarker evidence of myocardial injury, and hospitalizations were evident in all 4 patients.

• These patients had cardiac magnetic resonance imaging findings typical of myocarditis.