Low prevalence of hepatitis C virus antibody in men who have sex with men who do not inject drugs.

Objective. It is well documented that injection drug users (IDUS) have a high prevalence of antibodies to hepatitis C virus (HCV). Sexual transmission of HCV can occur, but studies have shown that men who have sex with men (MSM) without a history of injection drug use are not at increased risk for infection. Still, some health-care providers believe that all MSM should be routinely tested for HCV infection. To better understand the potential role of MSM in risk for HCV infection, we compared the prevalence of antibody to HCV (anti-HCV) in non-IDU MSM with that among other non-IDU men at sexually transmitted disease (STD) clinics and human immunodeficiency virus (HIV) counseling and testing sites in three cities. Methods. During 1999-2003, public health STD clinics or HIV testing programs in Seattle, San Diego, and New York City offered counseling and testing for anti-HCV for varying periods to all clients. Sera were tested using enzyme immunoassays, and final results reported using either the signal-to-cutoff ratio or recombinant immunoblot assay results. Age, sex, and risk information were collected. Prevalence ratios and 95% confidence intervals were calculated. Results. Anti-HCV prevalence among IDUs (men and women) was between 47% and 57% at each site, with an overall prevalence of 51% (451/887). Of 1,699 non-IDU MSM, 26 (1.5%) tested anti-HCV positive, compared with 126 (3.6%) of 3,455 other non-IDU men (prevalence ratio 0.42, 95% confidence interval 0.28, 0.64). Conclusion. The low prevalence of anti-HCV among non-IDU MSM in urban public health clinics does not support routine HCV testing of all MSM.