A Study of the Distribution of the Major Subtypes of Hepatitis B Antigen in Melbourne*

Summary: From 1st July, 1969 to 30th June, 1973, tests for hepatitis B antigen and antibody were carried out on 17,262 sera from inpatients of Fairfield Hospital and 17,360 sera submitted from other sources. An attempt was made to subtype all antigen positive sera by crossover immunoelectrophoresis, using monospecific anti ‘d’ and anti ‘y’sera prepared in the laboratory. Of 2,553 inpatients with acute viral hepatitis, 347 (13.6%) were found to be antigen positive. Eighty-seven of the antigens obtained from these patients could not be typed; of the remainder 191 (73.5%) were subtype Y. A predominance of this subtype was found amongst intravenous drug users and patients who had acquired their infection in the general community, whereas both subtypes were found in approximately equal numbers in hospital acquired infections.