Hepatitis B virus and hepatitis delta virus co-infection in drug addicts has been well described in Europe, the latter agent appearing to have been introduced there in the mid-1970's. Currently, similar data are scanty among United States addicts. We therefore reevaluated 99 drug addicts from three different geographic locations in the United States who had participated in a Veterans Administration Cooperative Study between 1972 and 1975. Almost all were asymptomatic, and all had been subjected to liver biopsy because of prolonged aminotransferase abnormalities. Stored sera were tested for antibody to hepatitis delta antigen (anti-HD) by radioimmunoassay and available liver biopsies examined for hepatitis delta antigen (HDAg) by immunofluorescence.
Overall, 19.2% were HBsAg positive, 9.1% HBeAg positive, 90% anti-HBc positive and 10.1%, positive for anti-HD. Anti-HD was identified in 42.1% of addicts who were HBsAg positive and in 3.3% who were anti-HBs positive. No correlation was found between HBeAg and anti-HD, but anti-HD was present significantly more frequently in those with chronic active hepatitis than in those with chronic persistent hepatitis. We conclude that hepatitis delta virus infection is common in HBsAg-positive drug addicts in the United States dating back to at least 1972 and probably earlier.