Three years ago, there was a mumps outbreak in the town I live in.
Of course, the Scott County Health department blamed it all on the unvaccinated kids, when ALL of the cases were among children and adults who HAD the vaccine.
Rather than say “Hmm... Maybe the vaccine isn’t protecting like we think it is”, they said “The vaccine only works if everyone is vaccinated, otherwise an unvaccinated carrier can make everyone sick! BAN THE NON VAXXERS!”
The vaccine makes you less likely to get it.
Having the Chicken Pox as a child doesn’t mean you won’t get Shingles. It just makes it less likely.
Rather than say “Hmm... Maybe the vaccine isn’t protecting like we think it is”, they said “The vaccine only works if everyone is vaccinated, otherwise an unvaccinated carrier can make everyone sick! BAN THE NON VAXXERS!”
It takes a bit of mathematics to understand what is going on here. Few, if any, vaccines are 100% effective in every recipient. Thus, if a vaccine is 97% effective, 3 people out of every 100 exposed will still get sick. On the other hand, the majority of non-vaccinated people who are exposed will get the disease. So you can have an outbreak situation where 8/10 unvaccinated get the disease and 30/1000 vaccinated people get the disease. In absolute numbers, more vaccinated people got sick, but the rate of illness was only 3% among the vaccinated as compared to 80% among the unvaccinated.