Seroepidemiologic behavior of varicella zoster virus infection in a semiclosed community after introduction of VZV vaccine.

A survey of varicella and measles has been made in a semiclosed institution housing infants and children in Osaka since 1950. Live measles and varicella vaccines were introduced into the institution in 1974 and 1975, respectively. Nine of 10 measles outbreaks occurred during the 24 years before use of measles vaccine, and only one occurred during the 9 years after introduction of measles vaccine. In contrast, the incidence of varicella outbreaks has not been reduced after introduction of varicella vaccine, although the rate of immune individuals in the population against varicella has been kept at 74.2% for the 8 years since 1975, which was higher than that against measles (65.8%) during the same period. All successfully vaccinated children, however, were resistant to clinical varicella, and the number of clinical cases has been markedly reduced. Using the fluorescent antibody to membrane antigen and varicella zoster virus skin testing, the kinetics of secretory, humoral, and cellular immune responses to VZV was examined in vaccinated and naturally infected subjects and found to be comparable in both groups during repeated exposure to varicella epidemics. These results suggest that the seroepidemiologic behavior of varicella would not be significantly altered after introduction of varicella vaccine, in contrast to that of measles since general use of measles vaccine.