Which is the most efficacious vaccine?
Measles vaccine has a protective efficacy of 95% with single dose while DPT vaccine has an efficacy of 70%. As far as polio vaccine is concerned the efficacy is quite variable for the three viral strains ranging from 65 – 90%. Moreover enteroviruse which are normally present in the intestine also antagonize the protective antibody response. However, Adsorbed tetanus toxoid has very high protective efficacy with vaccine failures recorded in less than 1% cases.