Reduction in hepatitis A antibody prevalence among young adults in Israel

Hepatitis A (HAV) is endemic in Israel. A number of developed countries have reported marked reductions in prevalence of antibodies. The objective of this study was to determine whether change in prior infection took place over a 7-year period and to investigate the sociodemographic characteristics of infection in Israel.

Recruitment into military service in Israel at the age of 18 is compulsory. Representative samples of male recruits were selected in 1977 and 1984. Antibodies to HAV were tested by solid phase radioimmunoassay in the 1977 sample and by an enzyme immunoassay in the 1984 sample.

HAV antibody prevalence in 1977 was 69% (95% confidence interval (CI) 65% to 72%) versus 54% (95% CI 49% to 59%) in 1984 (p < 0.0001). The reduction was evident in all ethnic-origin groups comprising the Jewish population. In 1984 the prevalence was 28% for Jewish men of European origin, 60% for Asian origin, and 80% for the North African origin group. A statistically significant independent effect of education was evident.

These findings point to a reduction in feco-oral transmission and hepatitis A virus infection in childhood in Israel, yet reveal considerable continuing ethnic and educational inequalities in prior exposure to infection. A potential for large outbreaks exists during transition from high to low endemicity, particularly in high-risk military populations. These populations are candidates for application of active hepatitis A vaccines now undergoing testing.