August 11, 2017
We know that hepatitis C can be transmitted through condomless anal sex in gay men and other men who have sex with men (MSM). The incidence of hepatitis C infection is higher in HIV-positive MSM compared to HIV-negative MSM.1 Until very recently, it was thought that the hepatitis C virus was being spread in these men through sexual activities where blood was present.
Recently, researchers in New York have found measurable levels of hepatitis C virus in the rectal fluid of HIV-positive MSM co-infected with hepatitis C.2 The levels of the virus in the rectal fluid correlated with the level of HCV in the blood. The amount of the virus present was high enough for hepatitis C transmission to occur through condomless anal sex.
This study suggests that the presence of blood may not be necessary for transmission to occur.
Researchers in New York City used rectal swabs to obtain rectal fluid samples from 45 HIV-positive MSM with hepatitis C co-infection.2 The hepatitis C viral load was measured in the rectal fluid and in a blood sample taken on the same day. To confirm that the swab did not injure the rectal lining, high-resolution anoscopy was performed on the first 30 men. This ensured there was no blood contaminating the rectal fluid samples.
All but two of the men were taking HIV treatment (ART), and 22 of the 43 men on ART (49%) had a detectable HIV blood viral load.
The hepatitis C virus was detected in the rectal fluid of 20 of 43 men (47%) in whom the viral load could be analysed. The hepatitis C blood viral load was much higher in men with detectable hepatitis C virus in the rectal fluid compared to men who did not have detectable hepatitis C virus in their rectal fluid. However, having a detectable HIV blood viral load did not affect the likelihood of having detectable hepatitis C virus in the rectal fluid.
The researchers noted that most of the men in this study were in the early stages of hepatitis C infection and so had lower levels of blood hepatitis C viral load than co-infected men with chronic hepatitis C infection. Therefore, they suggest that a greater proportion of men with chronic hepatitis C co-infection may have detectable hepatitis C virus in the rectal fluid than the men in this study.
The researchers concluded that the hepatitis C virus is present at high enough levels in rectal fluid to enable transmission of hepatitis C through condomless anal sex.
The new information provided by this study changes what we have traditionally thought about hepatitis C transmission among HIV-positive MSM. This is the first study to find conclusive evidence that the hepatitis C virus is present at high enough levels in the rectal fluid of HIV co-infected MSM to allow hepatitis C transmission through condomless sex, without the need for blood to be present.
While this is the first study to show that the hepatitis C virus can be present in the rectal fluid, other studies have also found hepatitis C virus in the semen of both HIV-positive3,4 and HIV-negative MSM4 with hepatitis C. In these studies, the virus was present in semen at high enough levels to transmit the virus through condomless anal sex.
These findings suggest condomless anal sex is a risk factor for hepatitis C transmission in HIV-positive MSM. Rectal trauma or blood may not need to be present for transmission to occur. It is important to educate MSM about the potential risk for sexual transmission of hepatitis C. All MSM who have condomless anal sex should be encouraged to talk to their healthcare provider about hepatitis C testing, whether or not they use drugs. Drug use is still likely the main route of hepatitis C transmission in MSM1 so harm reduction approaches should also be encouraged.
Zak Knowles is CATIE's web content manager. Before coming to CATIE, he worked as an HIV counsellor at Hassle Free Clinic, a sexual health clinic in downtown Toronto.
[Note from TheBodyPRO.com: This article was originally published by CATIE on Jul. 27, 2017. We have cross-posted it with their permission.]
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