The taliban started attacking polio vaccine workers and the UN suspended operations. Polio exists in Pakistan, Afghanistan, and Nigeria
According to a study conducted in Khyber Pakhtunkhwa, Pakistan, respondents misconceived the vaccine to be capable of causing harm to the immune system (93%), triggering adverse reactions 97.5%, to be against their social and moral values (95%), and to be not as good as traditional methods for treating children 98.5%
https://www.emro.who.int/emhj-volume-28-2022/volume-28-issue...
Is not a good rationale for making a decision. Parents, indeed anyone, shouldn't be worried about anything administered by a needle unless proper protocols are not followed, and they always should.
Nowadays it's a horrific notion and should never be done but back then the horrors of polio were so real and frightening that doing multiple vaccinations with one needle was of secondary importance (or so it seems). I've often wondered since how many cases of polio and hepatitis were actually spread back then by using a common needle (I've never understood why even back then doctors weren't concerned about this).
BTW, as I've mentioned previously, we kids were lined in the school's assembly hall in two long lines of over 100 that extended out the doors into the schoolyard—one line for boys and one for girls—and vaccinated immediately one after another. After every dozen or so kids the needle was changed.
It quickly got around that a new needle didn't hurt as much as a well-used one and we kids started jostling for positions in the line. We watched and counted how often the needle was changed then count our position in the line, we then we'd pay pennies to buy an optimal positions in the line (be first after the needle was changed). That being first was less risky never entered our minds.
At no time were we ever told about the dangers of sharing needles. As far as I am aware none of us got ill from that experience.
Incidentally, the whole school of about 1100 kids was vaccinated in about an hour and half—between the morning tea break and lunchtime. Compare that with the slow rigmarole of vaccination campaigns of today.
Which means someone at the CIA said, “Hey that thing that happened in the X-Files, let’s do that but for real!”
Spoiler:
It was the one where Mulder finds his sister’s record, then tears off the name to see his own underneath.
I doesn’t really matter though. The real world CIA vaccines were against Hepatitis B.
Even if the last stage of eradication is stubbornly slow, we have obviously been quite successful at limiting the number of cases.