I was vaccinated for polio and show no immunity. My grandparents who contracted polio show that they have immunity. The concept of herd immunity using vaccination can not happen. Vaccines do not produce the same results as getting the virus naturally, which produces lifetime immunity (at statistically higher percentages). My grandma still shows titers for pertussis at age of 85 (she had the whooping cough at age 10)...but according to the media, the Dtap vaccine wears off and the need to get boosters is essential. Funny, that these same doctors don't check titers to verify their statements. Since everyone produces a different immune response titer level...which can range anywhere from .5/ml to 15.00/ml (antibodies) and there is no science that can confirm what titer response equates to lifetime immunity...or determine any real protection....means it is statistically impossible to mimic "herd immunity"...as the 1929 study, which ironically determined the population needed to have 67% of the herd with lifetime immunity for "herd" protection. No or low-responders can still get the disease...so you will always have loopholes. If the solution is not perfect...then you can not force people to take something..especially if it won't work on them. My measles (yes I was vaccinated in the 70's) was not mild nor was it life threatening. Thank you for your response.