Acute myocarditis after coronavirus disease 2019 vaccination

To the Editor,

We would like to share our ideas on the article titled, “Acute myocarditis after the second dose of SARS-CoV-2 vaccine: Serendipity or atypical causal relationship?” by Cereda et al. (1), who concluded that “Post-vaccination myocarditis is an infrequent event.” The issue of cardiac complications after receiving the coronavirus disease 2019 (COVID-19) vaccine is an important one in cardiology. Sporadic cases with cardiac complications have been reported. Diagnosis is a clinical challenge. In a previous report, it was suggested that a complete evaluation, which includes a cardiac enzyme test (including troponin), electrocardiography, and imaging is required (2). In this study by Cereda et al. (1), all the evidence, except for the cardiac enzyme data, were provided. The difficulty is also owing to the lack of a complete study on the causal relationship. There are many possible interferences. The diagnosis is difficult if the patient has underlying heart disease. In addition, there is usually a lack of cases reported in the literature. The rarity of case reports might also be because of local policies in some settings for no report on COVID-19 vaccine adverse effects (3).