but that's out of 13m doses, so ~200 out of 13m. I'm not sure how that compares to the expected harm from catching covid but I imagine the vaccine still ends up massively favourable
This depends a lot on the probability of contracting Covid at all. Roughly speaking, if there's a 1% chance to contract the disease, the vaccine has to be at least 100 times safer. As the chance to catch Covid decreases over time, the risks associated with vaccines become more of a problem.
> As the chance to catch Covid decreases over time, the risks associated with vaccines become more of a problem.
This is a big assumption. It could also be that it becomes part of the virus background infections we all deal with except that it is high risk if you get it the first time.
When looking that the risk of an non vaccinated individual catching Covid today keep in mind that a lot of people have been vaccinated and the incidence numbers de-facto refer to incidences of the non vaccinated part of the population which would justify a smaller denominator than used (whole population).
That said, there is no guarantee that herd immunity will ever be reached at least in the US. If herd immunity isn't reached then it's basically guaranteed you'll get it eventually as the disease becomes a "background disease".
I'd wager it's approximately the same fraction of myocarditis cases that are reported in the unvaccinated group. There may even be a bias toward over-reporting myocarditis in the wake of a vaccine, as people are primed to look for side effects.