Immunity to varicella zoster virus in young Israeli adults

Chickenpox is a highly contagious childhood infection caused by varicella zoster virus, a virus of the herpes family. Although a mild and self-limiting disease in otherwise healthy children, chickenpox can be a complicated and even life-threatening disease in adults, pregnant women and immunosuppressed individuals. Among infants whose mothers had varicella during the first trimester of pregnancy, 2-3% will develop a congenital VZV syndrome that includes a combination of scarring, limb deformation, central nervous system impairment and ocular injury. In 1974, a live attenuated virus vaccine against VZV was developed in Japan and has been thoroughly tested for safety, efficacy and long-term effects. In March 1995 the vaccine was licensed in the U.S. for use in healthy children only.

To determine the rate of immunity to VZV in young Israeli adults.

On the assumption that a randomly picked sample of 18-year-old army recruits in Israel is representative of the general Jewish population, 900 sera samples were taken for 3 years (1985,1988,1992). The sera were analyzed for IgG to VZV with a commercial ELISA kit using microwells coated with VZV antigens.

A total of 98% of the samples tested positive for VZV antibodies. The difference in serologic values between the recruitment years was not statistically significant.

The majority of the Israeli population reaches adulthood already immunized against VZV, with immigrants having slightly lower immunity rates. Nonetheless, a few dozen cases of chickenpox are diagnosed in the IDF annually. These data should be taken into account when a vaccination program is devised. Should such a program be implemented, it would be interesting to repeat the serosurvey for comparison. A shift in the peak occurrence age might necessitate the administration of a booster vaccine at an older age.