How effective is the varicella vaccine?
Greater than 90% of susceptible, healthy adults seroconvert following two doses of varicella vaccine while only 80% seroconvert after a single dose. Seroconversion does not always result in full protection against disease. Effectiveness, the “real world” protection against disease, has been found to be 80% to 85% against any disease and greater than 95% against severe disease.
