Contents

Preventing transmission of hepatitis C during sex

Key points

  • The risk of hepatitis C transmission during sex is very low. However, it is possible in some circumstances. The risk of hepatitis C transmission through sex is generally considered to be much lower than through sharing of injection drug use equipment.
  • Hepatitis C transmission during sex has been reported among gay, bisexual and other men who have sex with men, particularly those who are living with HIV and some HIV-negative men with specific risk factors who are taking pre-exposure prophylaxis (PrEP; see below for more details).
  • Hepatitis C is passed blood to blood. Therefore, sex where blood is present (even if it is not visible) can pass hepatitis C. Transmission can happen through tiny cuts, breaks or tears in the skin or delicate mucous membranes (the wet linings) of the anus, rectum and genitals.
  • Certain factors have been associated with an increased risk of hepatitis C transmission, such as drug use before or during sex and, to a lesser extent, having a sexually transmitted infection, condomless anal sex, multiple sex partners, fisting without a glove, group sex, sex play that causes breaks in the skin (e.g., some BDSM play), sharing sex toys, sharing lubricant from the same container and anal douching.
  • For heterosexual couples with one exclusive sexual partner, the risk of sexual transmission of hepatitis C is very low.

Generally, the risk of hepatitis C transmission during sex is very low. However, there are some factors that can increase the risk, including some sexual activities with greater potential for blood-to-blood contact.

On this page, you’ll find information about the evolution of research on the sexual transmission of hepatitis C, factors related to the transmission of hepatitis C during sex and strategies to prevent hepatitis C transmission during sex.

Emerging concern about the sexual transmission of hepatitis C in some populations

Gay, bisexual and other men who have sex with men

For many years after the discovery of hepatitis C, there was no evidence of sexual transmission of the virus. Then in the early 2000s, hepatitis C outbreaks were reported among gay, bisexual and other men who have sex with men (gbMSM)1 living with HIV. Because the vast majority of the men in these studies did not report typical blood-related risks for transmission, such as injection drug use or possible medical or dental exposure, it was concluded that hepatitis C can be transmitted through sex among gbMSM living with HIV.

More recently, there have been reports of sexually acquired hepatitis C infection among some HIV-negative gbMSM, particularly those taking pre-exposure prophylaxis (PrEP) to prevent HIV. The role of PrEP in hepatitis C transmission is not well understood. Testing for sexually transmitted and blood-borne infections (STBBIs), including hepatitis C, is part of routine care for a person taking PrEP. Therefore, gbMSM taking PrEP are more likely to find out about a hepatitis C infection through routine testing, which can result in early diagnosis, linkage to care and treatment. Unlike the research studies among gbMSM living with HIV, in the studies of HIV-negative gbMSM on PrEP, drug use is often identified as a contributing factor to hepatitis C infection, including through party and play. Therefore, it is not known whether the risk is elevated in the absence of drug use.

Heterosexual people

Unlike with gbMSM, for heterosexual people there has not been any evidence that the sexual transmission of hepatitis C is a concern. Research with heterosexual couples with one exclusive sexual partner where one person in the couple has hepatitis C has demonstrated a very low or negligible risk of sexual transmission of hepatitis C. Among monogamous heterosexual couples, the estimated risk of sexual transmission of hepatitis C is a maximum of 1 infection per 190,000 sexual contacts. In this large study, about one-third of the couples reported ever having condomless anal sex; no specific sexual activities were related to sexual transmission of hepatitis C. Nevertheless, the factors that lead to an increased risk of sexual transmission among gbMSM (discussed in the next two sections) may also increase the risk among heterosexual people.

Other populations

Most research on the sexual transmission of hepatitis C has been among cisgender gbMSM and monogamous cisgender heterosexual couples. There is limited research related to other populations or the extent to which this information is applicable to other populations such as trans people. Further research is needed to better understand sexual transmission of hepatitis C among more populations.

How sexual transmission of hepatitis C occurs

How hepatitis C is passed during sex is not as well understood as other routes of transmission, such as injection drug use, and is still being explored. The risk of hepatitis C transmission through sex is considered to be low relative to the risk associated with injection drug use.

It is very well established that hepatitis C can be transmitted through blood-to-blood contact. Therefore, the risk of hepatitis C transmission through sex increases when blood is present, even when it is not visible. Transmission can happen through tiny cuts, breaks or tears in the skin or delicate mucous membranes (the wet linings) of the anus, rectum and genitals.

Not as much is known about the risk of hepatitis C transmission through genital and rectal fluids. Research has demonstrated that hepatitis C virus can reach sufficient quantity in seminal fluid to potentially pass hepatitis C. Studies suggest that exposure to semen may be a risk for transmission when other known risks are not present, such as the presence of blood, damage to skin or mucosal membranes, or sharing of drug use equipment. Emerging research has also indicated that rectal fluid can contain a sufficient volume of hepatitis C virus to potentially transmit hepatitis C. This research has been limited to small cohorts, typically involving men with HIV and hepatitis C co-infection, and this issue requires further investigation.

In most studies of the sexual transmission of hepatitis C, many different factors were involved that could contribute to risk. So far, research has generally focused on gbMSM because there is evidence in this population that hepatitis C can be transmitted through anal sex.

Factors associated with the sexual transmission of hepatitis C

  • Sexually transmitted infections (STIs): STIs that cause inflammation, ulcers or sores (such as herpes and syphilis) can increase the risk of sexual transmission, as these sores can be a route of entry for the hepatitis C virus.
  • Condomless anal sex: Irritation of or damage to the delicate mucosal membranes of the anus, rectum and penis can happen during anal sex, making it more likely for blood to be present and/or for tiny cuts or breaks to occur in the skin or mucous membranes. Having multiple sex partners increases an individual’s risk of sexual transmission of hepatitis C by increasing the possibility of having sex with someone who has hepatitis C.
  • Other activities where blood may be present:
    • fisting (involves inserting the hand into the anus or vagina) without a glove
    • group sex
    • sex play that causes breaks in the skin (e.g., some BDSM play)
    • sharing sex toys
    • sharing lubricant from the same container
    • anal douching

Other factors that impact the transmission of hepatitis C during sex among gbMSM

Research is ongoing into the many factors that may be contributing to the higher rates of hepatitis C transmission among some gbMSM. The following factors have been associated with an increased risk of transmission of hepatitis C during sex among some gbMSM.

Drug use before or during sex

Some people use certain drugs before or during sex to increase arousal, to facilitate disinhibition and to enhance or prolong sexual activities. In some contexts, this is known as party and play (PnP) or chemsex. PnP can include multiple methods of drug use, such as injecting, smoking/inhaling, snorting, or squirting dissolved drugs into the rectum (known as booty bumping or boofing). PnP can also impact the way people engage in sex and is associated with types of sex that may increase the likelihood of blood being present, such as prolonged sex or group sex.

Current or past experience injecting drugs has been identified as a main contributor to the higher rate of hepatitis C infection in gbMSM populations. Other types of drug use can also pass hepatitis C, including smoking and snorting drugs. The use of drugs during sex — and sharing equipment for using drugs — makes it difficult to know whether hepatitis C transmission is happening through sex or through shared drug use equipment.

HIV status

Although a history of injection drug use is the main contributor to hepatitis C infections among gbMSM, having HIV is also associated with a higher prevalence of hepatitis C in this population. The reasons for this are still being explored; they include potential biological factors such as HIV contributing to a weakening of the rectal mucous membrane of a person living with HIV, which may make it easier for the hepatitis C virus to pass through during receptive anal sex, or having a compromised immune system (in the case of an untreated HIV infection).

Because of the high rates of HIV among gbMSM, prevention efforts for this population have traditionally focused on preventing the sexual transmission of HIV. Highly effective methods to prevent HIV now exist that do not require the use of condoms, such as an HIV-positive person achieving and maintaining an undetectable viral load (U=U) or an HIV-negative person using PrEP. However, these methods do not prevent the sexual transmission of some other infections, such as hepatitis C.

In Canada, the prevalence of hepatitis C in HIV-negative gbMSM is higher than in the general population. New cases of hepatitis C among this group have been seen in particular among gbMSM who are using PrEP to prevent HIV, although the role of PrEP in hepatitis C transmission is not well understood. It is also possible that because testing for STBBIs, including hepatitis C, is part of routine care for a person taking PrEP, gbMSM taking PrEP are more likely to find out about a hepatitis C infection through routine testing.

Strategies to reduce hepatitis C transmission during sex

Incorporating hepatitis C testing into regular and targeted sexual health services can increase knowledge about hepatitis C and encourage screening, linkage to care and access to treatment. Early detection of a hepatitis C infection with linkage to care and treatment to cure hepatitis C minimizes the opportunity for the virus to injure the liver and reduces the chance of onward transmission.

The Canadian guideline on PrEP recommends that gbMSM on PrEP be tested annually for hepatitis C as part of routine screening for STBBIs.

Increase awareness of transmission of hepatitis C during sex among gbMSM. Talk with gbMSM clients about factors that can contribute to the risk of hepatitis C transmission during sex, as well as strategies for prevention. Stigma related to gbMSM sex and drug use can negatively impact access to education about the transmission of hepatitis C during sex, as well as access to other services related to safer sex, harm reduction and hepatitis C testing and treatment. These services should be offered in stigma-free, trauma-informed, culturally safe environments, tailored to the needs of the communities being served.

For clients who have had hepatitis C in the past and spontaneously cleared the infection or been cured through treatment, provide education on hepatitis C reinfection, prevention strategies, and linkage to ongoing screening for hepatitis C reinfection. If a client has a hepatitis C reinfection, they should be linked to treatment to cure the infection.

Safer sex practices are an effective way to prevent the transmission of hepatitis C, as well as other STBBIs, including HIV. The use of barrier methods, such as condoms or gloves, can lower the chance of blood-to-blood contact. Other safer sex practices include regular application of lubricant during prolonged sex, the use of lube from a personal (i.e., not shared) container and the use of sterile and unshared equipment for activities that can increase the likelihood of blood being present during sex (e.g., sex toys, BDSM equipment).

Safer drug use practices, including safer use of drugs for sex, are an effective way to prevent the transmission of hepatitis C. For injecting drugs, this includes the use of all new equipment including needles, syringes, filters, water and cookers each time drugs are used. For smoking drugs, this includes using a pipe or stem and mouthpiece that are for personal use and not shared. For snorting drugs, this includes using rolled paper or straws that are for personal use and not shared. For booty bumping or boofing (squirting dissolved drugs into the rectum), this includes using lube from a personal (i.e., not shared) container, sterile water, a personal container to dissolve and mix the drugs in the sterile water, and a needleless syringe or lube applicator that is for personal use and not shared.

Note:

  1. As this information reflects epidemiological data, we chose language that reflects current scientific literature (i.e., gbMSM). We recognize that this does not reflect the diversity of experiences, identities, relationships and sexual practices of people who may benefit from this knowledge.

Resources for service providers

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Revised 2022