Incidence of HBsAg, anti-HBs and subtypes ad and ay in a general hospital: correlation with clinical data and its significance as a public health problem.

During a period of four months, 9,418 individuals, comprising new hospital admissions, new employees and blood donors, were tested for HbsAg and 1,212 for anti-HBs. A high incidence of positivity for both was found in the different groups under investigation. Subtyping was carried out on acutely ill patients and carriers. Sbtype ay was common in acutely ill patients and among addicts and subtype ad in nonhepatitis patients and healthy carriers. The significance of these findings and possible measures for prevention of spread of the infection are discussed.