I think that assessing the occurrence of myocarditis in individuals who are vaccinated post COVID infection is important future research, if none is present. The possibility of there being an additive effect would likely be determined by the cause of myocarditis post infection/vaccination.

“It is under debate whether myocarditis in COVID-19 is primarily caused by the viral infection or whether it occurs secondary as a consequence of the host´s immune response, in particular by T-lymphocyte-mediated cytotoxicity or as a consequence of the cytokine storm observed during COVID-19 [25]”

The authors note that the cause of myocarditis from COVID-19 infection is up for debate. If it is related to “T-lymphocyte-mediated cytotoxicity” I am inclined to believe that there wouldn’t be an additive effect of vaccine + infection. My logic, albeit with minimal knowledge in virology, is that by have t cells created by the vaccine would be present prior to the virus. Thus able to respond prior to extensive cell infection and reduce the “T-lymphocyte-mediated cytotoxicity.”

Again, my logic my be flawed due to a misunderstanding or missing knowledge. I am open to corrections/reading to help guide me.