HCV prevalent in semen of MSM with HIV; anal infection likely
One-third of men who have sex with men coinfected with HIV shed hepatitis C virus into their semen at high enough concentrations to warrant protection against anal infection, according to a recently published study.
“That HCV is shed into the semen has been known for well over 2 decades,” the researchers wrote. “With multiple large epidemiological studies of discordant, stable heterosexual couples showing no HCV transmissions, the general assumption has prevailed that the level of HCV in semen was insufficient to transmit HCV through sex. However, with the emerging international epidemic of HCV infection among sexually active HIV-infected MSM, and our [previous] epidemiological study results that strongly implicated semen as the source of HCV during receptive anal intercourse, we revisited this assumption.”
Recent, chronic cases shed at similar rates
The researchers enrolled MSM with HIV, referred to Mount Sinai Medical Center for recent and chronic HCV between April 2013 and September 2014, into the analysis. Patients provided a clinical history including the likely route of HCV acquisition and underwent a physical and STD testing. The researchers collected three paired blood and semen samples at 2-week intervals, and quantified the HCV viral load in each.
Thirty-three coinfected patients were included in the analysis. Of these, 64% were categorized as having recent HCV infection, while the other 36% were considered chronic. Men with recent infection were younger than those with chronic infection, and demonstrated higher ALT levels and lower blood viral load. All participants reported receptive anal intercourse without a condom, and while nearly half reported injected methamphetamine use, injection equipment was rarely shared.
Results from 59 evaluable semen samples indicated a 27% rate of HCV shedding affecting 33% of participants. Men who shed had higher viral load in blood at baseline (P = .02) and upon sample collection (P = .002). The median HCV viral load among semen samples with HCV was 1.49 log10 IU/mL. Although a correlation between blood and semen viral load was only detected among patients with recent infection (P = .02), no difference was seen in the proportion of semen specimens in which shedding was detected (21% vs. 38%).
The frequency and concentration of shedding led the researchers to suggest infection could likely occur among this population following anal intercourse or other trauma.
“The rectum in HIV-infected people in general may be more vulnerable to the penetration of HCV into the bloodstream due to the mucosal changes accompanying the persistent depletion of rectal CD4+ lymphocytes due to HIV infection,” the researchers wrote. “With recent reports of sexual acquisition of HCV by MSM taking [PrEP] to prevent HIV infection, however, pre-existing HIV infection is unlikely to be necessary for acquisition of HCV via the rectum. Our data therefore strongly support that condoms should be used during anal intercourse among MSM to prevent HCV acquisition, regardless of HIV serostatus.”
Sexual HCV transmission common among MSM with HIV
Sexual intercourse appears to be an increasingly common transmission route for HCV among MSM with HIV, according to a meta-analysis published last year in AIDS.
Holly Hagan, PhD, professor at NYU College of Nursing and co-director of the Center for Drug Use and HIV Research, and colleagues reviewed data from more than 13,000 MSM with HIV followed in 17 studies focusing on HCV seroconversion or reinfection not attributable to injection drug use.
They found 497 cases of HCV infection over 93,100 person-years, translating to a pooled incidence rate of 0.53 per 100 person-years (95% CI, 0.49-0.58). This rate increased over time, growing from 0.42 infections per 100 person-years (95% CI, 0.23-0.77) to 1.09 infections per 100 person-years in 2010 (95% CI, 0.73-1.61). Analysis showed risk for infection to be greater among those reporting unprotected, receptive anal sex, and sex while high on noninjected drugs.
“The high reinfection rates and the attributable risk analysis suggest the existence of a subset of HIV-positive MSM with recurring sexual exposure to HCV,” Hagan and colleagues wrote. “Approaches to HCV control in this population will need to consider the changing epidemiology of HCV infection in MSM.” – by Dave Muoio
Disclosure: The researchers report no relevant financial disclosures.