Chances of infection given behavioural patterns, to be defined, × probability of damages post-infection, given demographics etc., to be defined¹

vs

100% for the chance of vaccination, × probability of damages post-vaccine (post 1 week, post 1 month, post 3 months etc.), given demographics etc., to be defined.

Probably you meant that according to available data, the probability of damages post-vaccine seem very low. Some people are concerned because those numbers do not seem to match the anecdotal they have around, so they would like to have better data - because some possible consequences are much more than nuisances. I say, if some entity kept an active monitoring ongoing, of the adverse side effects, much stronger reassurances - or less hesitance owing to confusion - could be given. I could only find passive monitoring around - USA, Europe, Australia, Canada etc.

¹The vagueness is such that in the context of this line, the last article I read mentioned values between 2.3% and 40%.