Hepatitis-B surface antigen and antibody: prevalence and persistence in institutionalized and noninstitutionalized persons.

A total of 426 persons were studied in an attempt to more clearly define the high prevalence of hepatitis-B surface antigen (HBsAg) seen among institutionalized persons. HBsAg was found in 63.4 percent of the children and young adults with Down's syndrome (DS) at the Central Wisconsin Center (CWC) and in 45.5 percent of those at the Northern Wisconsin Center (NWC). Significantly more subjects with DS had hepatitis-B antigenemia than age- and sex-matched non-DS institutionalized subjects. Antibody (anti-HBs) to HBsAg was found in 19.5 percent of the DS subjects at CWC and in 38.6 percent of those at NWC. The prevalence of anti-HBs was similar among DS and non-DS institutionalized subjects. None of the noninstitutionalized subjects had HBsAg in their serums and their anti-HBs prevalence was low (2.1 percent). HBsAg was found to persist for at least 10 years in both DS and non-DS institutionalized subjects. However, persistence occurred more frequently among DS subjects. Anti-HBs persisted at least 10 years among non-DS subjects, but DS subjects tended to lose antibody sooner. The study findings indicated that the high prevalence of HBsAg seen in institutionalized DS subjects at CWC and NWC were not related to the age of the subject at admission nor to the duration of institutionalization.