Low Prevalence of Hepatitis C Virus Antibody in Men Who Have Sex With Men Who Do Not Inject Drugs
August 31, 2007
"Large or repeated percutaneous exposures to blood such as through transfusion from unscreened donors or injection drug use have been the primary sources of infection" with hepatitis C virus (HCV), the authors wrote. "Sexual transmission occurs, but appears to be inefficient compared with other sexually transmitted viruses."
"Because non-IDU [injection drug user] MSM [men who have sex with men] without other known risk factors for HCV are not at increased risk, HCV testing is not recommended routinely for this population. Recent reports of increased HCV infection among HIV-positive non-IDU MSM have again raised concerns of sexual transmission of HCV. Consequently, some health care providers and MSM advocates believe all MSM should be tested routinely for HCV infection," wrote the authors. They undertook to examine this issue by comparing the prevalence of antibody to HCV (anti-HCV) in non-IDU MSM with that among other non-IDU men at STD clinics and HIV counseling and testing sites in three cities.
During 1999-2003, public health STD clinics or HIV testing programs in New York City, Seattle, and San Diego offered all clients HCV counseling and testing for varying periods. Enzyme immunoassays were used to test sera, and final results were reported using either signal-to-cutoff ratio or recombinant immunoblot assay results. Data on age, sex, and risk factors were collected. Prevalence ratios and 95 percent confidence intervals (CI) were calculated.
Among IDUs (male and female), anti-HCV prevalence at each site was 47-57 percent, for an overall prevalence of 51 percent. Among 1,699 non-IDU MSM, 1.5 percent (n=26) tested anti-HCV positive. Among 3,455 other non-IDU men, 3.6 percent (n=126) tested anti-HCV positive (prevalence ratio 0.42, 95 percent CI 0.28, 0.64).
"With decreasing resources to support prevention activities in publicly funded clinics, targeting HCV testing to those most likely to be infected is important," the authors wrote in their conclusion. "Although sexual transmission of HCV is possible, it appears to be inefficient, and testing MSM without a risk factor for which routine HCV is currently recommended is not supported by data in this report or other studies. HIV-infected people, including MSM, are an exception, and are recommended to be tested for HCV infection regardless of reported risk factors, as co-infection has important implications for progression of and therapy for both diseases."
Public Health Reports (2007)
09.2007; Supplement 2; Vol. 122: P. 63-67; Joanna Buffington, M.D., M.P.H.; Paula J. Murray, M.P.H.; Karen Schlanger, M.P.H.; Linda Shih, M.P.H.; Tracy Badsgard; Robin R. Hennessy, M.P.H.; Robert Wood, M.D.; Isaac B. Weisfuse, M.D., M.P.H.; Robert A. Gunn, M.D., M.P.H.