Duration of immunity to hepatitis B vaccination in institutionalized mentally retarded patients.

Susceptible individuals of an institution for the mentally retarded (20 residents and six staff members) were vaccinated with Hevac B Pasteur (5 micrograms, months 0, 1, 2, 14). There were protective levels of anti-HBs in 75% of residents and 100% of staff members after 15 months from the first dose of the vaccine. After a 4-year follow-up period, there were persistent and protective levels of anti-HBs in 80% of residents, compared with 66% in staff members. In addition, no clinical hepatitis B infections were observed during this period.