The evidence that smallpox vaccine was instrumental in ending smallpox is weak. The effectiveness of the vaccine is quite questionable given the published record. The disease declined along with many unvaccinated others, and its highly unclear whether the vaccine helped. When the disease was finally eradicated, it was the culmination of a huge campaign of early quarantine.
The smallpox vaccine is acknowledged to have killed almost as many as smallpox in vaccinated countries in much of the 19th century. These deaths are undisputed to my knowledge, but the putative savings seem illusory.
The evidence that polio vaccine was instrumental in ending polio is weak. According to an article publiished in JAMA 1959, less than a third of the patients at the Detroit "Polio" epidemic even had the polio virus or antibodies to it. Perhaps "polio" epidemics had some other cause, such as DDT. The polio vaccine is also acknoweldged to have caused many cases of paralysis and polio and to continuing to cause cases of vaccine-derived polio. Again, these cases appear established, but any gains may be illusory.
Tetanus deaths have fallen by far more than can be attributed to the vaccine. The vaccine may prevent some deaths, but it is rare for anyone in the country to die of tetanus now, and the vaccine is only protective by maybe a factor of 50. So if nobody was vaccinated, only at most some dozens of people may die. Not good, but compare the downsides below.
Rabies maybe has saved some people.
The evidence that other vaccines have saved large numbers of lives is very weak. Measles cases are down since measles vaccine was introduced, but the number of deaths per year in the country was only a few hundred before the vaccine in widespread use, and had been falling dramatically, down 99.96% before vaccine introduction in England. Very possible measles deaths would have gone away as fast or faster without vaccine.
The evidence that vaccine–induced herd immunity exists and is helping is weak. In fact, there's evidence vaccines are causing repeated outbreaks.
There is significantly stronger evidence for vaccines causing harm in a variety of ways: including contributing to infant deaths, and likely infecting humanity with SV-40 and Chimpanzee Coryza Virus, and possibly HIV. Chimpanzee Coryza Virus, called RSV in humans, kills millions worldwide. Mostly this is laid out in a separate topic:http://truthsift.com/search_view?id=406&nid=4083
Assuming vaccines are causing damage, we can estimate the carnage from some of the regressions.
Regression indicates that each 7 vaccines in the national series is associated with an increased IMR of 1/1000. Extrapolating from that estimate, vaccines kill 4/1000 infants in the first year in the US. If vaccines are responsible for the autism epidemic, and there's virtually no evidence they aren't and considerable evidence they are, they are seriously harming another 2% or more of the population.
HIV kills a few tens of thousand in the US. SV-40 contributes to some cancers. Vaccine aluminum causes extreme obesity in mice, perhaps vaccines are contributing the the epidemics of obesity and diabetes. 7% of the children now have autoimmune problems and the average child more than one chronic ailment such as allergies or neurodermatitis in a German study.