I'd assert that in such an experiment I would already be doing my part to reduce the impact of covid mainly due to where I live and minorly by my choices of how I live. The extra utility of that vaccine is effectively lost on me when that is figured in. When there is 0 utility then any altruistic action is nothing more than signaling. If I could be convinced there is serious utility for others by getting vaccinated then of course I would get it. Nobody seems willing to put real numbers to this, its simply "DO IT EVERYONE!"
Lets say there are only 2 reasons to get the vaccine:
1) To protect yourself
2) To protect all those you care for.
I'm not worried about 1 due to the apparently very low likelihood I will have some terrible personal covid outcome.
I'm not worried about 2 due to the apparent very low likelihood of even catching covid.