Marked decrease in the incidence and prevalence of hepatitis A in the Basque Country, Spain, 1986–2004

Abstract

The aim of this study was to determine changes in the epidemiology of hepatitis A virus (HAV) infection in the Basque Country, Spain, and to evaluate their implications for vaccination strategies. A total of 1356 persons were enrolled in a study of the prevalence of anti-HAV in 2004 and compared with two previous studies (1986–1987 and 1992). The selection method and the characteristics of the population were similar in the three studies. A marked decline in the seroprevalence in all age groups (P<0·001) and in the incidence of cases/100000 inhabitants (from 38·0 in 1986–1988 to 2·9 in 2002–2004) were observed. The mean age of patients with hepatitis A increased from 17·7 years in 1986–1992 to 21·2 years in 1993–1998 and 25·3 years in 1999–2004 (P<0·001). Between 1997 and 2004, 20% of patients were hospitalized. The changes observed have occurred rapidly causing a change in the epidemiological pattern from middle-high endemicity (1986) to low endemicity (2004).