Seroprevalence of antibodies to hepatitis a virus among children in Northern India

Hepatitis A virus (HAV) and hepatitis E virus (HEV) are responsible for enterically-transmitted acute viral hepatitis. Infection with both HAV and HEV are endemic in developing countries. HAV infection is transmitted predominantly by close person-to-person contact(1). In endemic areas, HAV infection is common during childhood. In this age group, the infection is usually mild and asymptomatic, and induces anti-HAV antibodies, which confer life-long immunity against reinfection(1). On the other hand, HAV infections in adults are more often symptomatic and severe. It is generally believed that most residents of endemic areas are exposed to HAV infection by early adulthood and are therefore immune to it; if so, vaccination against HAV may have little role to play in these areas. HEV infection, on the other hand, appears to be transmitted predominantly through contaminated water(2) and person-to-person transmission is infre-quent(3). Exposure to this infection appears to be less frequent among children as compared to HAV infection(4). Early studies of HAV seroprevalence in India showed that 90% of Indian children in the age group of 5-10 years had anti-HAV anti-bodies(5). This observation is of particular interest because of recent availability of an effective vaccine against HAV. However, more recent reports from our country show that anti-HAV antibody may not be as frequent in children and young adults as was previously believed(6-7). In light of these conflicting observations, we decided to study the preva-lence of anti-HAV among a group of northern Indian children