Epidemiology and clinical impact of hepatitis D virus (delta) infection.

We tested sera collected between 1976 and 1984 from 362 persons in a variety of epidemiologic categories with acute and chronic hepatitis B and from 76 hemophiliacs and drug addicts with hepatitis B antibodies for hepatitis D markers. Hepatitis D markers were common in hemophiliacs, drug addicts, Afghanistanis, prisoners and hemodialysis patients; rare in persons from other hepatitis-B endemic areas, persons with sporadic hepatitis B and homosexual men; and absent in health-care workers and institutionalized mentally retarded persons. No change was observed in the frequency of this infection during the 9 years of this study. We found hepatitis D markers in 5% of patients with acute hepatitis B, 1 of 3 with fulminant hepatitis and in 4 (1 in a homosexual male) of 12 episodes of acute hepatitis in hepatitis B carriers. Hepatitis D markers were more frequent in chronic liver disease (18%) than in asymptomatic hepatitis B carriage (2%), but there was no association between severity of chronic hepatitis and hepatitis D. These findings indicate that, to date, health-care workers and institutionalized mentally retarded persons have been spared from infection with this agent but suggest that homosexual males may not continue to be spared. Even in an area nonendemic for hepatitis D, this agent contributed to 20 to 30% of chronic hepatitis B and acute hepatitis superimposed on chronic hepatitis B infection.