According to George E. Cawthon :

Lots of people objected to the polio vaccine. And
that bad batch was from a single lab and ended up
in Idaho (where I live) where a lot of kids got
polio from the shots.

More important was the controversy between the
Saulk vaccine (based on dead virus) and the Sabin
vaccine which was an attenuated but live
vaccine. The latter was effective with kids and
spreading immunization but it killed a lot of the
older relatives of the kids vaccinated.

Desperate times call for desperate measures.

The very first smallpox vaccine killed 1 out of 6. Those were better
odds than not being vaccinated in those days. [This predated the
famous cowpox vaccine]

Another vaccine that has had bad press is the diptheria (whooping cough)
vaccine. Which was reported to have a bad outcome in 1 out of 10,000
vaccinations. Yet... as I recall, the odds of catching diptheria
without being vaccinated are something like 1 in 6, and "bad outcomes"
from catching it is also something like 1 in 4 or 6. Or, in other words,
bad outcomes one in 24 to 36 for not being vaccinated.

Certainly, we need to be aware of the failure rates and strive to
drive them downwards. But expecting zero is unrealistic, and we
should not overexaggerate the dangers based on off-handed remarks
about "lots".
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.