July 22, 2011
This report suggests high-risk sexual behavior as a cause of HCV transmission among HIV-infected MSM in New York City. Unprotected receptive anal intercourse with ejaculation and sex while high on methamphetamine were the most important predictors of HCV infection. Results from phylogenetic analyses suggest networks of HCV transmission among these men. The findings of high-risk sex, concurrent noninjection-drug use, and phylogenetic clustering are similar to those observed among cohorts of HIV-infected MSM with HCV infection in Northern Europe and Australia.4 A notable finding from this study and those in other countries is the association of noninjection, recreational drug use (e.g., methamphetamine use) with the acquisition of HCV infection.
Sexual transmission of HCV is considered to be an inefficient and rare mode of transmission.6 However, concurrent HIV infection results in increased HCV RNA levels (viral load),7 which are thought to increase infectiousness of HCV acquired through sexual contact. Of further concern among persons who are coinfected is that HIV accelerates HCV disease progression, even in its early stages.2 End-stage liver disease and hepatocellular carcinoma, both usually resulting from chronic HCV infection, are now leading causes of death not attributable to acquired immunodeficiency syndrome (AIDS) among HIV-infected persons in the United States.8
The findings in this report are subject to at least three limitations. First, recall of events such as ejaculation by sex partner up to 12 months before HCV diagnosis can be imperfect. For example, the findings should not be interpreted to definitively exclude acquisition of HCV by some men through unprotected receptive anal intercourse without ejaculation, even though this variable did not exert a significant independent effect on HCV infection in the multivariable analysis. Second, refusal to acknowledge injection-drug use is not uncommon, and other types of stigmatizing risk behavior also might be underreported. Such social desirability bias was addressed by using a self-administered questionnaire and assuring each patient that his responses would not be shared with his primary-care provider. Finally, study investigators relied on patient referrals from HIV-care providers outside Mount Sinai, and referral bias might have occurred; however, the number of referring providers was fairly sizable (n = 35).
Sexual transmission of HCV among HIV-infected MSM is more widespread than this one study demonstrates. A recent U.S. report described HCV-antibody seroconversions among HIV-infected MSM without a history of injection-drug use.9 A recent European report that examined a group of studies, primarily from Europe, found substantial increases, particularly during 2002-2007, in the incidence of HCV infection among HIV-infected MSM, demonstrating just how serious the epidemic has become among these men.10 Hepatitis C should be added to the list of infections spread among HIV-infected MSM who have sex with HCV-infected partners. HIV-infected patients should be counseled and reminded that unprotected sex between HIV-infected partners can transmit other infections, including HCV. In addition to HCV screening for MSM newly diagnosed with HIV, routine HCV screening using both ALT and antibody testing should be considered for HIV-infected MSM, particularly those with high-risk sexual behaviors or concomitant ulcerative sexually transmitted diseases (e.g., syphilis and herpes simplex virus).† Finally, newly diagnosed HCV infections among HIV-infected MSM should be reported to state and local health authorities.
† Based on CDC's Sexually Transmitted Diseases Treatment Guidelines, 2010, available at www.cdc.gov/mmwr/preview/mmwrhtml/rr5912a1.htm.
What is already known on this topic?
Infection with hepatitis C virus (HCV) is a major cause of morbidity, and, if left untreated, can lead to chronic liver disease and death. HCV transmission occurs primarily through percutaneous exposure to blood (injection-drug users are at greatest risk), but the role of sexual transmission has not been well defined.
What is added by this report?
Sexual transmission was found to be the most likely mode of transmission of HCV among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) in this study in New York City.
What are the implications for public health practice?
These findings, and those elsewhere, suggest that sexual transmission of HCV can occur undetected among HIV-infected MSM in the absence of injection-drug use. Health-care providers should consider HCV testing for HIV-infected MSM with high-risk sexual behaviors or concomitant ulcerative sexually transmitted diseases (e.g., syphilis and herpes simplex virus).
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