Much evidence supports the hypothesis that Australia antigen (Au) causes viral hepatitis. We found Au(1) in 30 of 43 drug abusers with hepatitis (69.8%), a similar frequency to posttransfusion hepatitis (56.3%), but different from infectious hepatitis (30.1%). There were no distinctive histologic features in liver biopsies from drug abusers. Two of nine drug abusers with Au(1) followed serially, developed persistent Au(1); two of 22 other Au(1) hepatitis patients had persistent Au(1) Australia antigen was found in nine of 215 "normal" addicts (4.2%), significantly different from the general population (two of 2,412), but not different from 261 nonaddicts exposed to hepatitis by multiple blood transfusions (3.8%). Acute hepatitis in drug abusers is likely mainly viral, not toxic in origin.
Sutnick AI, Cerda JJ, Toskes PP, London WT, Blumberg BS. Australia Antigen and Viral Hepatitis in Drug Abusers. Arch Intern Med. 1971;127(5):939-941. doi:10.1001/archinte.1971.00310170147021