Myocarditis and COVID-19 mRNA vaccination

To the Editor:

We would like to comment on “Acute myocarditis after SARS-CoV-2 vaccination in a 24-year-old man” by Cimaglia et al.¹ They reported an interesting case and concluded that “myocarditis may also occur after administering the vaccine against SARS-CoV-2.” Regarding pathomechanisms, Cimaglia et al. discussed the role of autoimmunity.¹ If there is an immunopathological process, an abnormal immunoglobulin profile should be demonstrated. An abnormal immune response might be a cause but there are also other possible causes, one of which is the induction of hyperviscosity by vaccination.² A relationship between hyperviscosity and acute myocarditis has been confirmed³ and hyperviscosity induced by vaccination might also be a cause of myocarditis.⁴

Conflicts of interest

The authors have no conflicts of interest to declare.