Shouldn't this kind of research have been carried out before billions of people were vaccinated? Is it ethical to enforce vaccinations (via mandate) with these matters unresolved?
1. Vaccinate LOTS of people.
2. Accept that the hospitals are full of covid patients, so people who break a leg can't get a bed.
Option 2 isn't very desirable. It only took months to find some vaccines that make option 1 clearly better than option 2. (Some other vaccines failed, but you don't hear about those.)