SALIVARY SAMPLING FOR HEPATITIS-B SURFACE-ANTIGEN CARRIAGE - A SENSITIVE TECHNIQUE SUITABLE FOR EPIDEMIOLOGIC STUDIES

Vertical transmission from mothers to infants of hepatitis B infection results in a high incidence of carriage in children with long-term co nsequences, and is the focus of current immunization strategies. The u se of saliva for hepatitis B surface antigen (HBsAg) screening in a co untry with an intermediate to high prevalence of chronic carriage was investigated. We recruited 88 Thai women with known HBsAg status (44 p ositive, 44 negative) who were attending an antenatal clinic. The coll ection of saliva was acceptable to all patients. Aspects of technique regarding collection and handling in a tropical setting are discussed. Comparing the detection of HBsAg in saliva to serum using a commercia lly available serological test kit without modification, the sensitivi ty was 92.0% (95% CI 84.8-99.5) and the specificity was 86.8% (95% CI 76.0-97.6). Population acceptability and safety advantages along with a high sensitivity strongly support the use of salivary sampling for e pidemiological surveillance of hepatitis B virus.