Hepatitis B antigen in a psychiatric hospital population

Sera from 1283 patients and 73 staff members from Cherry Farm Psychiatric Hospital were screened for hepatitis B antigen over a five year period, following a single confirmed case of type B hepatitis in one villa. Apart from the presenting case, 10 asymptomatic carriers of hepatitis B antigen were detected, three of these being from the same villa and possessing the same antigen subtype as the presenting patient. Only two of 26 Down's syndrome patients and two of 44 Polynesian patients were positive. No staff members were positive. A case of frank hepatitis B occurred in a male nurse accidentally pricked with a needle contaminated with blood from one of the carriers. The low prevalence of hepatitis B antigen in this population for the mentally ill is possibly related to the reduced patient contact resulting from the isolated villa type of accommodation.