Serum antibodies against hepatitis A virus among subjects of medium and low socioeconomic levels in urban Santiago

Background: The epidemiology of hepatitis A virus (HAV) infection is closel y associated to the level of hygiene and sanitation of the population. Newl y industrialising areas experience a transition from high to intermediate e ndemicity, which is characterized by a shift in the exposure age to HAV fro m early childhood to school ages or adolescence. Aim: To measure the preval ence of HAV antibodies in subjects living in urban Santiago. Subjects and m ethods: A HAV antibody, survey in five medium and low socioeconomic level u rban districts of northern Santiago, was conducted in 1996. Healthy subject s aged 1 to 39 years old were recruited from randomly selected households. Results: File hundred three subjects were studied. Anti HAV antibodies were found in 13.2, 29.5, 59.6, 78.1, 95.6 and 98.2% of individuals aged 1 to 4 , 5 to 9, 10 to 14, 15 to 19, 20 to 29 and 30 to 39 years old, respectively . Conclusions: The profile of positive antibodies is compatible with an int ermediate pattern of transmission of HAV. The current data supports the ide a that infection is shifting towards older ages. A progressive increase in the number of susceptible school age children and teenagers is propitious f or the occurrence of common source hepatitis A outbreaks.