HCV is primarily a blood borne infection, so sex that includes blood-to-blood has the highest risk. In MSM, this has led to the view that the risk of transmission is high when using sex toys, fisting, “slamming”, chemsex, and “rough sex”.
Although HCV has been found in semen, and also in vaginal fluid, until now it has been unclear whether these fluids are infectious, because HCV is generally at very low levels. Even though HCV levels can be high in semen and do not always match HCV levels in blood, it was thought that contact with sexual fluids was unlikely to be a major route of HCV infection. The risk of HCV sexual transmission is low from vaginal sex, in monogamous, HIV negative heterosexual couples in which one partner has HCV.
A recent study presentated at BHIVA 2017 suggests that prevention messages around sexually transmitted hepatitis C in MSM may need to change. Prevention advice has tended to focus on sexual practices which could result in blood to blood transmission, by causing injuries in the rectum (so from for example, fisting, rough sex, and use of sex toys), or from sharing needles (chemsex, slamming). However, several recent studies have identified merely receptive anal sex without condoms, and without the previously mentioned factors – so if you like, “vanilla” sex! – as a risk factor. In about 20% of cases, HCV was only associated with receptive condomless anal sex. The researchers recommend that HIV-negative gay men who can be identified as being at a higher risk of hepatitis C are offered testing for the virus. This would include PrEP users, men reporting chemsex or injecting drug use and the sexual partners of people with hepatitis C.
They also recommend that gay men living with HIV are advised that hepatitis C can be passed on through anal sex without a condom. Even though the risk might be lower than from blood-to-blood transmission, nonetheless, there is a real risk..
The full article can be read here.