[Prevalence of hepatitis B infection in institutions for the mentally retarded. Epidemiologic characteristics in the province of Vizcaya].

The prevalence of hepatitis B virus (HBV) infection was studied in 346 subjects (148 employees and 198 mentally retarded) in four institutions for the mentally subnormal in Vizcaya-Spain. The prevalence of markers in the overall group was 32.6%; 13.5% in the employees and 46.9% in the mentally retarded. Early age and institutionalization time increases the risk of infection in the mentally retarded group, but not in the employees group. 220 subjects (118 employees and 102 mentally retarded) had negative HBV markers and were vaccinated with recombinant-DNA hepatitis B vaccine. The immunogenicity was 80% and the weight-height index the only factor implicit in the group of subjects no seroconverters. The reactogenicity of vaccine was 6.7%.