Edmonston-Zagreb strain of measles vaccine: epidemiologic evaluation in Yugoslavia.

According to epidemiologic data in Yugoslavia, a high level of immunity (95%) must be attained in the susceptible population between eight months and 30 years of age for the eventual eradication of measles (to cut off the seasonal peak and to prevent the epidemiologic wave). Where the vaccination rate produced a lower level of immunity (e.g., 85% and 67%), the cyclic wave did not disappear completely but was greatly reduced. Live measles vaccine prepared from a further-attenuated Edmonston-Zagreb strain was used for vaccination in Yugoslavia.