[Nich]

also, it's not 0 or 2x.

You have a baseline chance of myocarditis and the RELATIVE risk ratio is 2:1 (getting vaccinated) or 15:1 (getting infected). in ABSOLUTE numbers baseline might be 0.001% and getting vaccinated kicks that up to 0.002

You can play the same game with vaccine effectiveness. Say it is RELATIVE 90% effective at stopping you getting symptoms / going to hospital. in ABSOLUTE numbers your initial risk may have been 0.002%, vaccine bumped that to 0.001%.

Of course, I've played enough Diablo to know a 0.001 PROC isn't to be sneezed at.