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Prevalence of hepatitis C in Swiss MSM similar to general population
In Switzerland, hepatitis C virus infections are not more prevalent in HIV-positive men who have sex with men than in the general population, suggesting that widespread screening for this population is unneeded, recent study data found.
Researchers recruited 840 men who have sex with men from a gay health program that provides outreach and examinations at various sites. The participants were aged 17 to 79 years.
The study participants completed an anonymous questionnaire detailing sexual practices and other hepatitis C virus risk factors, such as injection drug use, non-injection use of cocaine or amphetamines, tattoos, piercings, past blood transfusions, and diagnosis of HIV or other sexually transmitted infections. Participants also were asked about their country of origin.
Blood samples were drawn from all study participants and were screened for HIV, syphilis and HCV. The HCV screenings tested for past (antibodies) and present (core antigen, RNA) HCV infection.
Of the participants, 19 (2.3%) reported previous diagnosis of HIV. Of the 821 without a reported HIV diagnosis, 579 (70.5%) self-reported as HIV negative, 188 (22.9%) said they were unaware of their current HIV status, and 54 (6.6%) chose not to divulge their status.
Seven men tested positive for HCV antibodies, and two were positive for HCV core antigen and HCV-RNA. Both men originated from countries other than Switzerland, and one was from a country where incidence of HCV is more than 3.5%. Among the 821 MSM without a reported HIV diagnosis, the serum prevalence of HCV was 0.37% (95% CI, 0.12-1.69), and one man had replicating virus (0.12%; 95% CI, 0.02-0.69).
There were significant univariable associations of lifetime HCV infection found with the following: HIV diagnosis (OR=72.7); tattoos (OR=10.4); non-injection drug use of cocaine or amphetamines (OR=8.8); and country of origin other than Switzerland (OR=8.5).
Among MSM without reported HIV diagnosis, the only variable that showed a modest link to positive HCV serostatus was being tattooed (OR=8.3).
“Although trends in the spread of HCV among MSM should be closely monitored, we currently see no reason for promoting routine HCV-testing for MSM without known HIV infection in Switzerland,” the researchers wrote.
Disclosure: Some of the researchers report various financial ties with Abbott, Bristol-Myers Squibb, Boehringer, Gilead, Janssen, Merck and Roche.
Perspective
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The authors perform a cross-sectional study of 840 MSM at two sites of a gay health center to look for prevalence of hepatitis C. Of these, 19 (2.2%) reported being HIV-infected. Overall, seven men (0.8%) were positive for HCV antibodies and two of these were HCV RNA positive. Among the men not diagnosed with HIV, three had HCV antibodies (one HCV RNA positive), yielding a prevalence of 0.37% so that the number needed to test to detect one active infection was 821. Among those with a known HIV diagnosis, the antibody prevalence was 21.1% with 5.3% with HCV RNA.
Schmidt and colleagues state that in Switzerland, HCV screening among non-HIV infected MSM should not be promoted since they are not at an increased risk for hepatitis C over the general Swiss population. It is worth noting that their HCV prevalence in HIV-uninfected men is much lower than in the Multicenter AIDS Cohort Study (MACS), which is a study of MSM from four urban areas of the United States. In the MACS, the HCV antibody prevalence at entry into the cohort was 2.6% in HIV-uninfected men without a history of drug use and was 41% in HIV-uninfected MSM with a prior history of drug use (Seaberg EC, JVH in press).
In this study, 3.3% of the HIV-uninfected men reported injection drug use but only a quarter of them had HCV antibodies. This is surprising since in most cohorts at least 50% of injection drug users are HCV antibody positive and in many closer to 90% have HCV antibodies (reviewed in Sulkowski. Clin Infect Dis. 2005;15:S263-9).
It is not clear if this cohort is representative of the MSM population in Switzerland. The reported HIV prevalence was 2.2% and published prevalence among MSM is in the 8% to 11% range (Marcus. BMC Public Health 2012;12:978). Thus, these men who go to a gay health center may not be representative of the general MSM population in Switzerland so the data may not be generalizable. A total of 6.6% of the men did not disclose their HIV status, which may account for some but likely not all, of the difference in HIV prevalence.
Overall, these men had a small number of unprotected anal intercourse partners (median 1). In a study from the MACS in the US (Witt. Clin Infect Dis. 2013;57:77-84), unprotected receptive anal intercourse was the strongest behavioral risk factor for incident HCV in MSM. Other studies have shown that fisting is a risk factor, which only 4% of the study population reported engaging in.
Because it is difficult to know how representative this study population is compared with HIV-uninfected MSMs worldwide, clinicians should ask all MSMs about risk factors for HCV and test them if risk factors are present regardless of HIV status.