[Incidence of antibodies against hepatitis virus A (anti-HA) in a non-selected urban population].

Anti-HA antibodies were determined by radioimmunoassay according to the HAVAB-ABBOTT technique in 244 subjects, of whom 194 without hepatic involvement, 25 with non B hva and 25 former non B hva patients. Anti-HA anti-bodies were found in 67% of the healthy subjects and 100% of the patients and former hva cases. The incidence of anti-HA antibodies increases with age being in 30% of children and 83.5% of adults. A peak incidence was found between the ages 21 and 30 years. In the district investigated subclinical infection with HVA was frequent, beginning in childhood and up to the age of 30 years. The qualitative HAVAB test is adequate for epidemiological investigations; a quantitative variant is necessary for the diagnosis.