Human immunodeficiency virus and hepatitis delta virus in homosexual men. A study of four cohorts

The prevalence of hepatitis delta virus antibodies was determined in four cohorts of homosexual or bisexual men positive for hepatitis B surface antigen who were evaluated between April 1984 and April 1985. Antibodies to hepatitis delta virus were found in 16 of 106 men in Los Angeles (15.1%; 95% confidence interval [CI], 8.3% to 21.9%); 6 of 64 men in San Francisco (9.4%; 95% CI, 3.5% to 19.3%); 1 of 76 men in Pittsburgh (1.3%; 95% CI, 0.03% to 7.1%); and 0 of 52 men in Chicago (0%; 95% CI, 0% to 5.6%). From 44.0% to 65.4% of men negative for hepatitis delta virus but one (P < 0.0001) were positive for antibodies to human immunodeficiency virus (HIV). In multivariate analysis, infection with hepatitis delta virus was associated with intravenous drug use (adjusted odds ratio [OR] = 6.7, P < 0.01), with sexual activity as measured by number of partners (adjusted OR = 8.4, P < 0.01), and probably with rectal trauma (adjusted OR = 3.9, P = 0.17). As with HIV infection, prevalence of hepatitis delta virus infection in homosexual men differs by location and is most likely transmitted both sexually and parenterally.