The changing epidemiology of viral hepatitis A in Israel.

ABSTRACT

BACKGROUND: Between 1970 and 1979, there was an increase in the incidence of viral hepatitis in Israel with a shift of peak incidence to an older age in the Jewish population, followed by a declining trend during the early 1980s. In July 1999 universal immunization of infants against hepatitis A was introduced. OBJECTIVE: To evaluate the chan-ges in the epidemiology of viral hepatitis A in Israel during the past decade. METHODS: Viral hepatitis is a notifiable disease in Israel and cases are reported to the regional health offices, which in turn provide summary reports to the Ministry of Health's Department of Epidemiology. The data in this study were derived from the summary reports and from results of seroprevalence studies. RESULTS: Following the increase in the incidence of reported viral hepatitis (mainly due to type A) between 1970 and 1979, the rates then stabilized and around 1984 began to decline until 1992. Since then there has been a slight increase. Whereas until 1987 the rates were consistently higher in the Jewish population, since then they are higher in the Arab population. The shift in the peak age-specific incidence from the 1-4 to the 5-9 year age group observed in the Jewish population around 1970 occurred 20 years later in the Arab population. The previously described seasonality is no longer evident. Recent seroprevalence studies indicate that by age 18 years only about 30-40% of the Jewish population have anti-hepatitis A antibodies. CONCLUSIONS: The decline in the incidence of hepatitis probably reflects the changing socioeconomic condition occurring at different times in the two major population groups. Since hepatitis A accounts for almost all the acute viral hepatitis in Israel, the universal vaccination of infants introduced in 1999 should substantially lower the morbidity within the next few years.