Changing epidemiology of hepatitis A virus infection--a comparative study in central eastern Poland (1990-1999).

A comparative seroepidemiological study (1990 vs. 1998/99) on HAV infection, was carried out in population from middle-eastern Poland. Anti-HAV was tested in 1450 subjects from 0 to over 50 years of age and the results were compared with those observed in 1990, in 1000 individuals of the same age range and from the same geographical area. Overall anti-HAV prevalence was 58.4% in 1990 vs. 30.6% in 1998/99. This decline of HAV infection in Polish population indicates that the number of non-immune adults is increasing, with higher risk of symptomatic infection in the near future. The surveillance and prevalence data presented here have implications for developing the strategy for use of hepatitis A vaccine.