Sexual Transmission of HCV Is Uncommon Among Heterosexual Injection Drug Users

By Liz Highleyman

Traditionally, it has been assumed that hepatitis C virus (HCV) was rarely transmitted through sexual activity, largely basis on the low rates (0%-5%) observed in epidemiological studies of monogamous heterosexual couples.

In recent years, however, this assumption has been called into question due to outbreaks of apparent sexually transmitted HCV infection among gay men in the U.K. and Europe. Most such cases have been seen in HIV positive men who have sex with men (MSM), but a few have been reported in HIV negative MSM and HIV positive women.

In the U.S., HCV is most commonly transmitted through shared use of drug injection equipment. However, the contribution of sexual transmission among injection drug users (IDUs) is unclear, and prior studies have produced conflicting data.

As reported in the June 1, 2007 Journal of Infectious Diseases, researchers assessed multiple risk factors for HCV infection using a novel multilevel modeling technique designed to overcome the limitations of previous research. The analysis included data on 265 drug-using couples in East Harlem in New York City.

Results

. In a multivariate analysis, significant individual risk factors for HCV included a history of injection drug use, tattooing, and older age.

. At the couple level, HCV infection tended to cluster within couples, and was accounted for by drug-injection behavior.

. Individual-level and couple-level sexual behavior was not associated with HCV infection in this model.

Conclusion

In conclusion the authors wrote, "Our results are consistent with prior research indicating that sexual contact plays little role in HCV transmission. Rather, couples' injection behavior appears to account for the clustering of HCV within heterosexual dyads."

The greater apparent risk of sexual transmission of HCV among gay men may be due to specific practices such as anal sex, fisting, group sex, and use of intrnasal recreational drugs, that are more common in the MSM population.

05/04/07

References

JM McMahon, ER Pouget, S Tortu. Individual and Couple-Level Risk Factors for Hepatitis C Infection among Heterosexual Drug Users. Journal of Infectious Diseases 195(11): 1572-1581. June 1, 2007. Read Study

JA Hahn. Sex, Drugs, and Hepatitis C Virus. Journal of Infectious Diseases 195(11): 1556-1559. June 1, 2007.