Two studies show how men who have sex with men could contract hep C through sex
by Larry Buhl
Because the hepatitis C virus (HCV) is most effectively transmitted by blood, there’s a general acceptance in the medical community that the risk of contracting the virus through unprotected anal sex is low. But two studies are shedding new light on how the virus could be transmitted during sexual activity.
A team of researchers at the Icahn School of Medicine at Mount Sinai in New York published two research studies that challenge the belief that HVC requires blood or even so-called “traumatic sex” to be transmitted to a partner. They concluded that, even though the virus needs to get into the bloodstream, it doesn’t have to get there through the blood of another.
Their first study showed that one third of HIV-positive men who have sex with men, with recent HCV infection have some level of HCV in their semen. Hepatitis C virus was found in sixteen (twenty-seven percent) of semen specimens from eleven (thirty-three percent) of the men.
Daniel Fierer, MD, the lead investigator of the study, explained that even low HCV levels could be enough to infect a partner.
“[HCV] is a relatively less infectious virus than HIV because HCV has to enter the bloodstream,” he said. “But it can take advantage of an opening or cut. If semen with HCV is in the rectum the friction itself could transmit, especially if there is bleeding.”
One takeaway from the study, Fierer says, is that PrEP, while effective in preventing HIV transmission, offers no protection for other STDs and non-STDs [HCV] which can be transmitted through anal intercourse.
Fierer, an infectious disease specialist, said he has seen several men on PrEP with hepatitis C infections who did not engage in high risk behaviors (IV drug use) for HCV infection. He also cautioned that HIV infection is not required to acquire HCV. “Someone who’s HIV undetectable can still transmit HCV.”
In the second study Fierer’s research team looked at rectal fluid, the mucous that coats the rectal area, to determine whether it could transmit the virus to someone who tops.
The team tested forty-five men who have sex with men (MSM) coinfected with HIV and HCV to see if the hepatitis C virus showed up in their rectal fluid. Researchers found that about half (forty-seven percent) had detectable HCV in their rectal fluid, and they also found positive correlation between HCV viral load in someone’s blood and HCV detectable in their rectal fluid.
The studies found that about 1/3 of participants shed HCV into their semen and about 1/2 into their rectal fluid. But since only about 1/3 of men in both studies had chronic HCV infection, where blood HCV levels are higher than during the short early HCV phase, based on their subgroup analyses Fierer speculated that the overall proportion of HIV-infected men with HCV infection who shed HCV into their body fluids was probably underestimated and could be closer to about 3/4.
The findings could also mean risk for a bottom engaging in threesomes or group sex, even when latex is used.
“The rectal fluid can coat the penis, and it can coat a condom or a fist or a toy. If one of those is then inserted into the rectum of another, [HCV] infection could happen,” Fierer said.
Fierer added that hepatitis C is not a “professional sexually transmitted agent. STDs like chlamydia or gonorrhea are efficiently passed along through sexual activities. HCV can be transmitted during sex,” even though it’s less likely. “But do you really want to take that chance with a virus like hepatitis C? It’s curable now but not everyone has access to the new meds.”
The belief that HCV is rarely transmitted through sex, Fierer adds, was based on studies of monogamous heterosexual couples, studies he believes to be limited. “There were three large studies with stable, discordant couples where the infected partner did not infect the uninfected partner. But they had been together a while, and if the infection was going to happen it would have happened already.”
In addition, studies showed that hepatitis C hadn’t entered a group of men who had a high prevalence of HIV, “and the assumption was that if HCV were sexually transmitted, it should show up at the same rates, but it wasn’t.”
Fierer admits that his two studies are small, and that other issues need to be better understood when determining the true risk of contracting HCV from anal sex. “I want to know why the rate [of the virus] in semen is variable. And we need a more nuanced understanding of the variables involved in how HCV actually gets into the bloodstream.”
Larry Buhl is a radio news reporter, screenwriter, and novelist living in Los Angeles. Follow him on Twitter @LarryBuhl.