Seroprevalence of hepatitis B virus markers and risk factors in patients and staff of an Italian residential institution for the mentally disabled

We conducted a cross-sectional study to evaluate the prevalence rate and risk factors for hepatitis B virus (HBV) infection among residents and staff at the Fatebenefratelli Institute in San Colombano in the province of Milan. We tested serum from 510 patients and 165 staff members. In addition, a medical record and a completed questionnaire were obtained from each patient. A total of 338 (66.5%) residents were found to have markers of HBV infection, including 29 (5.7%) who were identified as carriers. Thirty-nine members of staff (24.1%) showed evidence of HBV infection but only 1 (0.6%) was identified as a carrier. Among patients the prevalence rate of HBV was significantly associated with length of stay and age at admission, as it was with length of employment among staff members. The hepatitis B vaccine was offered to all patients and staff in the institution during 1994. A total of 143 (84%) patients and 111 (90%) members of the staff were vaccinated in the same year. To prevent the further spread of HBV infection in this institution, all current and future residents and staff members should be screened for serological markers for HBV and subjects identified as being susceptible should be vaccinated according to a compulsory routine policy.