Hepatitis B infection in a day school for mentally retarded students: transmission from students to staff.

We carried out a seroepidemiologic study to evaluate the transmission of hepatitis B virus (HBV) from students to staff in a day school for mentally retarded students. Of 505 students tested, 37 (7.3 per cent) had HBsAg; 74 per cent of HBsAg-positive sera tested were HBeAg-positive. Of 162 staff members tested, 21 (13.0 per cent) were HBV marker positive and two (1.2 per cent) had HBsAg; specialized educators and teachers showed the highest HBV marker prevalence (22.2 per cent and 21.3 per cent, respectively). The prevalence of HBV markers among staff was independently associated with classroom contact with a HBsAg-positive student, duration of employment at the school, and previous work with mentally retarded individuals. The incidence of HBV infection among teaching staff with regular classroom contact, estimated by logistic regression analysis, was 2.6 per cent per year. This observation indicates that teaching staff in schools for mentally retarded students with direct classroom contact may carry an occupational risk of HBV infection.