“but very few (if any) addressed the halachic question”
The very first comment on the thread answered your “question”
with a halachic question the premise has to make sense, and be grounded in reality.
Even if for whatever reason you think the vaccine may cause fertility problems, (whether or not you think the new Oreo flavor does the same) It STILL isn’t a question.
People are not faulted for following doctors. Halacha in fact obligates you to do so.
Aye what do we do if Doctors disagree? Fear not ! halacha addresses that too!