Risk of anti-hepatitis A virus in an urban population in Jakarta

In Indonesia, prior studies to identify risk factors for hepatitis A have not provided prevalence estimates in the general population. This study was conducted to measure the prevalence of antibody to hepatis A virus (anti-HAV), and to identify high risk populations and risk factors in preparation for an immunization program. Using randomly selected households in Jakarta, 987 adults and adolescents aged 15 and older were interviewed in 1994 to ascertain demographic information, socioeconomic status and risk factors for anti-HAV. Blood samples were taken for anti-HAV, SGOT and SGPT. Eighty seven percent of the participants were positive for anti-HAV. Risk increased with age, reaching an 18.8-fold risk (95 percent CI 8.0-44.2) among those aged 51 years and over, compared to the reference group aged 15-20 years. Anti-HAV was strongly associated with low socioeconomic status (odds ratio 4.9, 95 percent CI 2.5-9.4). Immunization against hepatitis B was associated with reduced risk of anti-HAV, and a history of foundice increased the risk of anti-HAV. Immunization against HAV should be targeted to adolescents and young adults, particularly those in higher socioeconomic groups, who are least likely to have natural immunity and who are most susceptible to HAV infection in adulthood.