Sociodemographic factors and the declining prevalence of anti-hepatitis A antibodies in young adults in Israel: implications for the new hepatitis A vaccines.

In order to examine changes in the epidemiology of hepatitis A virus (HAV) infection in Israel during the past decade, a sero-epidemiological study was carried out in 1989 in a random sample of 1153 members of the permanent army, aged 21-30 years. Of the males 59.2%, and 54.3% of the females were anti-HAV antibody positive (p = 0.22). At all ages, the highest prevalence was in those of North African origin, followed by those of Asian, native Israeli and Western origin. There was a marked decline in the prevalence of antibodies in later birth cohorts, (from 74.4% in those born in 1959-1960, to 47.8% in those born in 1967-1968). Age, ethnic origin, number of siblings, more than two younger siblings and smoking were independently significantly associated with anti-HAV antibodies. Despite an overall decline in family size in later birth cohorts, ethnic differences remain prominent. These findings suggest that when the new active hepatitis A vaccines become available, their use in small children should dramatically reduce the incidence of diseases in highly endemic areas by limiting intrafamilial spread of the disease.