Sample size of 25 out of a population of... how many tens of millions of young (EDIT: not actually young) men? Seems quite small, and perhaps not sufficient to draw any conclusions. I wonder what the results will show...
> myocarditis is another manifestation reported during SARS-CoV-2-infection [24]. 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].
Interesting!
> Finally, we cannot provide a definitive functional proof or a direct causal link between vaccination and myocarditis. Further studies and extended registry are needed to identify persons at risk for this potentially fatal AEFI and may be aided by detailed clinical, serological, and molecular analyses which were beyond the scope of this study.
So in total, out of 25 young men, 20 showed signs of cardiac damage. It's suggestive and merits more research. On the other hand, the authors offer no real ideas about how the damage could have happened, other than to observe that since similar damage happens as a result of COVID-19, maybe the immune response is the culprit (provoked by the vaccine, similarly as by the disease).
Far from any sort of smoking gun. It's important to keep that in mind.