I found an interesting study that will let me say something positive about vaccines for a change:
The authors looked at all the reported US national reports of child tetanus cases for the years 1992-2000. They found there were 15 cases in the 8 year span. No deaths, but some hospitalizations. 12 of the 15 were un-vaccinated. (I’m assuming all or most cases get reported, which I think is likely. Otherwise you’d need a factor for reporting frequency in the back of the envelope calculations below.)
The first thing their survey tells you is, the tetanus vaccine seems to protect against tetanus. Something like 90% of the population is vaccinated according to the CDC, yet only 20% of the tetanus cases are. That suggests the vaccine is something like 97% effective at protecting against tetanus, which I think makes it probably more effective than any other I know of. If every child were vaccinated the number of cases over the 8 year period might well have dropped from 15 to the 3 vaccinated cases they had or maybe 4 if they got another.
The second thing it tells you is, even if all the vaccinated had been UNvaccinated so they all got it 30 times as much, you might only expect 100 cases nationwide over the 8 year span. (How does that compare to the number of serious complications from the vaccine?) The chance of an unvaccinated child getting tetanus over the 8 year span seems maybe to be something like 1/500,000 or less, figuring that roughly 50 million vaccinated kids generated 3 cases so vaccinated maybe has 3/50 million, unvaccinated maybe 30 times as great or 1/500k.
(The 10% unvaccinated are maybe 5 million who generated roughly 10 cases, which checks the math.)
According to this history https://sites.google.com/site/tetanuswiki/project-definition: there used to be 200 cases per 100K people per year. (Caveat: This may be an overestimate for children, so I’m not quite apples to apples to the above figures which are of children. There maybe should be a fudge factor for that.) A frequency of 1/500. So tetanus frequency has dropped by a factor of maybe roughly 30000, of which maybe a factor 30 was due to the vaccine and 1000 was due to other factors unknown. I don’t see how this drop can possibly be attributed to herd immunity, since tetanus is not passed between humans. So tetanus is another example of a disease that largely vanished where a vaccine seems NOT to have been the major factor in the vanishing.