Lack of evidence of sexual transmission of hepatitis C virus in a prospective cohort study of men who have sex with men.

Objectives: We studied the prevalence and incidence of hepatitis C virus (HCV) infection in the ongoing Omega Cohort Study of men who have sex with men (MSM).

Methods: From January to September 2001, consenting men (n = 1085) attending a follow-up visit to the ongoing Omega Cohort Study were tested for HCV. If the test results were positive for HCV, we compared them with test results from previous serum samples collected from the time of entry into the original cohort study to determine the time of infection.

Results: HCV prevalence at entry was 2.9% and was strongly associated with injection drug use (32.9% vs 0.3%, P<.0001). Only 1 seroconversion was identified in 2653 person-years of follow-up (incidence rate = 0.038 per 100 person-years). The seroconverter was an active injection drug user who reported needle sharing.

Conclusions: Sexual transmission of HCV among MSM appears to be rare.