Reports from Europe and New York City have suggested a growing Hepatitus C Virus (HCV) epidemic among HIV-positive men who have sex with men (MSM).1,2 Furthermore, data indicate that sexual transmission may be the mechanism of HCV acquisition among noninjection drug using (IDU) MSM,3,4 in which case serosorting (i.e., unprotected anal sex between HIV-positive partners) may fuel HCV transmission.5 However, other studies from Seattle, San Diego, and New York City find low prevalence of HCV among non-IDU MSM.6 A sexually-driven epidemic of HCV among HIV-positive MSM could have significant impact on the health of HIV-positive MSM. We, therefore, assessed HCV prevalence and changes in HCV prevalence among HIV-positive MSM through serological testing of specimens collected during surveys conducted in 2004 and 2008.
As part of the US National HIV Behavioral Surveillance (NHBS) system, cross-sectional surveys of MSM were conducted in San Francisco in 2004 and in 2008, using a standardized time-location sampling protocol.7 Serum samples from those participants, who tested HIV-positive stored from the 2004 and 2008 survey rounds, were tested for HCV antibodies (Advia/Centaur HCV, Siemens Healthcare Diagnostics Inc, Deerfield, IL) at the San Francisco General Clinical Laboratory. Results were merged with behavioral data which included history of injection drug use and history of being diagnosed for HCV by a doctor or nurse. Point prevalence estimates were adjusted for the survey design; the change in prevalence from 2004 to 2008 was assessed using the χ2 test. We additionally examined mortality data from our local HIV/AIDS case registry to corroborate findings from our cross-sectional surveys. The NHBS protocols were reviewed and approved by the University of California, San Francisco Institutional Review Board; testing of the anonymous specimens for HCV antibody received nonresearch determination.
A total of 92 and 115 HIV-positive specimens from 2004 and 2008, respectively, were tested for HCV antibodies, including 69 and 82 non-IDU MSM, respectively. The prevalence of HCV among all HIV-positive MSM was 15.2% (95% confidence interval [CI], 7.7%–22.7%) in 2004 and 8.3% (95% CI, 1.9%–15.5%) in 2008, indicating no statistically significant change (P = 0.45). Limiting the sample to non-IDU MSM, HCV prevalence was 8.7% (95% CI, 1.9%–15.5%) and 4.5% (95% CI, 0.1%–8.9%) in 2004 and 2008, respectively. The apparent decline in HCV prevalence was not statistically significant (P = 0.33). Of note, few HCV infections appeared to be new; the majority of HCV-seropositive MSM provided a history of being previously diagnosed, both in 2004 (71.7%) and in 2008 (94.0%). Finally, 58% (95% CI, 46.0%–9.9%) and 55% (95% CI, 43.9–65.2) of non-IDU MSM reported engaging in unprotected anal intercourse in the past 6 months in 2004 and 2008, respectively. Stimulant use among these respondents was moderately high with 41% (95% CI, 28.7%–52.5%) and 26% (95% CI, 16.7%–35.5%) reporting use of stimulant drugs (i.e., methamphetamine, cocaine, crack) in 2004 and 2008, respectively.
HCV prevalence among HIV-positive MSM in San Francisco was moderately high overall and among non-IDU MSM, compared to the general US population prevalence of 1.3% to 1.9%.8 We found no evidence of a change in prevalence between 2004 and 2008, suggesting that HCV infection among HIV-positive MSM, even when engaging in sexual and/or substance use risks, in San Francisco does not yet follow the pattern among HIV-positive MSM in Europe and New York (Table 1). To further assess the apparent stabilization or possible decline in HCV prevalence, we examined mortality among MSM known to be living with HIV with and without coinfection with HCV in our local HIV/AIDS case registry from 2001 to 2005 (the years for which mortality data are complete). Overall, mortality was higher among those coinfected: for IDU, the difference in an annual average mortality was 22% with HCV compared to 7% without HCV, and for non-IDU average annual mortality was 11% versus 7% with and without HCV, respectively (San Francisco Department of Public Health, unpublished data, 2010). These data suggest that some of the apparent stabilization may be attributed to excess mortality; however, the figures also suggest that the rate of new HCV infections was not high enough to replace deaths from past infections. The latter observation corroborates our community survey findings weighing against a recent rise in HCV incidence among HIV-positive MSM. We acknowledge the limitations of the small sample size of MSM and non-IDU MSM in our surveys. Strengths of the samples are that it follows the standardized surveillance methodology conducted in cities nationally and was community-recruited rather than originating from HIV or STD clinics.1,2,6 Thus, our approach may be more representative of MSM nationally and can be examined in other jurisdictions and tracked over time. We also note that the use of antibody as opposed to nucleic acid testing will likely result in an underestimation in the prevalence of HCV infection. Finally, although NHBS and our case registry data do not entirely overlap temporally, we do believe that this is an acceptable use of existing data to corroborate disease outcomes. Although a low and no apparent rise in HCV is reassuring for the present, a high level of surveillance vigilance, including nucleic acid testing, is needed to detect changes in the epidemiology of HCV among groups at risk for HIV, careful assessment of the modes of HCV transmission, as well as routine screening among persons in HIV care.
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