Studies Investigate Presence of Hepatitis C Virus Among Gay and Bisexual Men
August 11, 2014
Hepatitis C virus (HCV) can infect the liver, causing inflammation that injures this organ. If HCV is left untreated, injury can spread throughout the liver and this organ consequently becomes increasingly dysfunctional. As a result, the eventual appearance of serious symptoms related to liver damage occurs and a person's quality of life degrades. HCV infection also increases the risk for liver cancer.
The Spread of HCV
HCV (and other germs) can be spread in a number of ways, including:
Transfusions, Blood Products
In Canada and other high-income countries today, the spread of HCV by transfusions of blood or platelets or by use of clotting factor is extremely rare. This safety arises from screening of the blood supply for HCV, implemented in the 1990s.
However, in some other countries the blood supply may not have been screened so immigrants to Canada may have inadvertently been infected in their country of origin, as might Canadians who received transfusions abroad.
Unsterilized Medical Equipment
In high-income countries, medical equipment that is meant for reuse is sterilized, so HCV infection via this route is extremely unlikely. This is not always the case in other parts of the world.
Another source of HCV infection may be the reuse of needles and syringes in mass treatment or mass vaccination campaigns in other countries. Again, this is not an issue in Canada today.
Researchers estimate that the risk of transmission from infected mother to infant is between 4% and 7% and higher when the mother is co-infected with HIV.
Sharing equipment for injecting street drugs is the major source of new HCV infections in high-income countries today. This includes needles, syringes, cookers and other equipment for injecting. HCV infection can also be spread from sharing straws and rolled-up currency notes used to inhale powders or crystals, and pipes used for smoking crack.
HCV can be spread through condomless vaginal sex among heterosexual people. However, among monogamous HIV-negative couples, sexual transmission of HCV is highly unusual, even when condoms are not used.
Further research is required with heterosexual women, both HIV positive and negative, to assess their risk for acquiring HCV infection during condomless anal and vaginal sex.
HCV can be spread among men who have sex with men (MSM), particularly HIV-positive MSM, and we explore this through the findings from several studies later in this report.
Tattooing and Body Piercing
Use of contaminated equipment for tattooing and body piercing can also lead to the spread of HCV.
For more information about HCV prevention (and treatment) visit CATIE's Hepatitis C section.
The Outbreak Among MSM
For at least the past decade, an outbreak of sexually transmitted HCV has been occurring among MSM. The vast majority of these cases have occurred in HIV-positive MSM. Researchers in four high-income countries -- Sweden, Switzerland, the Netherlands and Australia -- have been investigating this outbreak among both HIV-negative and HIV-positive MSM. Their findings suggest that in MSM who are HIV negative and who do not engage in high-risk sexual and/or drug-using behaviour, HCV infection is relatively rare.
The Swedish Study
Doctors at Stockholm's leading sexually transmitted infections (STI) clinic offered HCV testing to MSM who did not have HIV. This study took place between October 2012 and March 2013. Blood samples that tested positive for HCV antibodies were later analysed with other tests, including those that could detect HCV's genetic material (RNA). The antibody test can reveal if someone was exposed to HCV in the past but it cannot distinguish between past and current infection. The RNA test can reveal if HCV is being produced by infected cells and can uncover active and therefore current infection.
A total of 1,008 out of 1,061 men (95%) agreed to participate in the study. Their ages ranged from 16 to 82 years.
Six of the men tested positive for HCV antibodies and further testing revealed the following:
- two of the six men had active HCV infection (HCV RNA was present)
- in the remaining men, three were previously exposed to HCV but had overcome this infection
- in the case of the sixth man, his immune system appeared to have inadvertently made antibodies that were similar to anti-HCV antibodies detected by the first round of screening for this study; doctors concluded that he had not been exposed to this virus
- none of the six men were co-infected with HIV
Focus on the Three Men With Past Exposure to HCV
There were several possible causes of exposure to HCV in these men, which the doctors identified as follows:
- one man had been in a medical facility in South America
- another man had a former partner with whom he injected street drugs and their sexual activity included fisting
Doctors did not have information about the third man's risk factors.
Focus on the Two Men With Active HCV Infection
One of these men had a history of genital herpes and syphilis but no other STIs at present. This is an important point because these and other STIs can cause inflammation, sores or lesions (sometimes painless) that can act as an entry point for other germs, like HCV. He also disclosed that he did not engage in rough anal sex or sharing of sex toys.
The other man with HCV infection had a rectal Chlamydia infection and disclosed that he had engaged in fisting since 2012.
Overall, the Swedish team found that less than 1% (0.2%) of MSM in their study had ongoing HCV infection. This rate of HCV infection in HIV-negative MSM is similar to what is observed among the average HIV-negative Swedish population who do not use street drugs.
The Swiss Study
Researchers at a sexual health clinic in Zurich recruited MSM for their study between January 2009 and July 2010. All blood samples were tested for HCV antibodies and HCV-related proteins. Samples that tested positive for either of these were further analysed for HCV's genetic material. In total, the researchers analysed data from 840 MSM, whose ages ranged between 17 and 79 years. Researchers relied upon participants' self-reports about their HIV status.
As with the previously mentioned Swedish study, a large proportion of men (95%) who were offered HCV testing consented.
- 19 men (2.3%) disclosed a previous HIV-positive test result
- 579 men (71%) stated that they had tested negative for HIV
- 188 men (23%) did not know their HIV status
- 54 men (7%) refused to disclose their HIV status
Overall, seven men tested positive for HCV antibodies. None of the seven disclosed a previous diagnosis of HCV. Furthermore, HCV RNA was detected in only two participants, indicating active infection. Both of these men had immigrated to Switzerland from other countries. In one of those countries HCV infection is relatively common.
Overall, less than 1% of MSM in this study had HCV infection, broadly similar to what is seen among the average HIV-negative Swiss person who does not use street drugs. Among MSM who stated that they did not have HIV infection, researchers found a marginal statistical link between having tattoos and HCV. Bear in mind that the design of the Swiss study was cross-sectional. Such study designs are unable to make definitive links between cause and effect. That is, in the case of the Swiss study, researchers cannot be certain that unsafe tattooing was the source of HCV infection in some men.
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