The yellow fever vaccine works though. The covid vaccines are all somewhere on the level of very ineffective down to snake-oil. Yellow fever also is actually a serious disease while covid is for the absolute huge majority nothing more than a cold.
Are you sure? Available numbers have varied. Are you sure that it is not just a superficial appearance, and that damage could be revealed by a low-level assessment? Some people do not drink or smoke, you know - they want to be optimal, not "it's just a scratch".
Those people who judge the potential damages from covid as negligile but for limited cases would have little reason for reclutance towards vaccination, which would gain the advantage of further reducing those chances.