Hepatitis-B virus infection in children and adults in Northern Nigeria: a preliminary survey.

Hepatitis-B surface antigen (HBsAg) and its corresponding antibody (anti-HBs) have been detected by radio-immunoassay in children and adults and in adult expatriates in Zaria, Northern Nigeria. The exposure rate to hepatitis-B virus (frequency of HBsAg and anti-Hbs) was found to vary from 59% in children under five years to 72.5% in adults over 30 years of age, while the frequency of HBsAg alone was 40% and 10% respectively. The anti-HBs prevalence rates rose progressively with age and reached a peak at 62.5% in adults. Five of 32 adult expatriates (15.6%) were positive for anti-HBs. The factors contributing to the high exposure rate in the indigenous population in this region require further study to enable judicious use to be made of preventive measures.