[marcosdumay]

I understood that the same way as you.

By itself, this carries a high "we found a link between green jelly beans and acne" flavor (xkcd/882). But even if it's not there, there are a lot of other complicating factors.

Those studies about myocarditis were important because they derived improvements on the procedure to apply intramuscular vaccines. But that improvement by itself is enough to invalidate any findings you will find on any such study from that time.