Falling incidence and prevalence of hepatitis A in northern Spain.
The prevalence of hepatitis A virus antibodies was studied using a commercial ELISA method. 2,214 subjects were included, 1,211 in 1992 and 1,003 during 1986-87. In 1992 the seroprevalence rates among subjects 1-9, 10-19, 20-29 and 30-39 years old were 2.4%, 21%, 57.6% and 87.5% respectively, as compared with 7.7%, 37.9%, 80.6% and 98.1% respectively, in a similar group of subjects studied 5 years earlier (p < or = 0.001). The reported number viral hepatitis cases declined from 35.0 per 100,000 people in 1984 to 8.9 per 100,000 in 1992. Concurrently, the age when contracting the disease rose. The mean age for patients acquiring hepatitis A was 15.5 in 1986-88 and 20.1 in 1991-92. The decline in incidence and prevalence of HAV infection indicates a progressive and continuous decrease in HAV circulation in this geographical area.