April 3, 2014
We reported on the Swedish and Swiss studies because they were published in 2014. However, it may also be useful to review an Australian study with MSM published in 2010. In that study, researchers assessed HCV infection in 1,427 HIV-negative men recruited between 2001 and 2004. HCV antibodies were relatively uncommon, found in about 1% of men. This is broadly similar to the proportion of HCV in the average HIV-negative person in Australia. There was no trend of an increase over time in MSM in this study. The most significant risk factor for HCV was injecting street drugs. Two men with HCV antibodies who did not report injecting street drugs had other possible risk factors -- body piercing and tattooing.
In the same study, between 2001 and 2007, five men developed antibodies to HCV. Only one of these five disclosed that he injected street drugs. Four of the men had sexual contact with HIV-positive men (in this study HCV is almost 10-fold more common among HIV-positive men). Three of the men disclosed the use of sex toys with their partners (sharing sex toys without first disinfecting them can inadvertently transmit germs), one reported fisting and one reported condomless sex.
In the same Australian study, 245 HIV-positive men were offered testing for HCV during 2005 and 2007, with 23 testing positive for HCV antibodies. According to the researchers, 18 of these 23 men responded to the question about whether they had ever injected street drugs, with 16 of these 18 (89%) disclosing that they had done so.
In their concluding remarks, the Australian researchers stated: "As [injecting street drugs] is probably more highly stigmatized than sexual-risk behaviour in this population, it is possible that [injecting street drugs] was under reported" in their study.
Researchers in Amsterdam have been keeping track of HCV (and HIV) in their city for several decades. To do this they regularly seek blood from participants and also ask them detailed questions about sexual and substance-using behaviour. Among a total of 777 HIV-positive men, HCV infections increased over time. In 1995, about 6% of HIV-positive MSM had HCV and by 2008 this figure had climbed to nearly 21%. After this time, the rate of new HCV infections in this population seems to have stabilized.
Among these 777 men, only 11% disclosed that they had ever injected street drugs. The usual high-risk sexual and substance-using risk factors were linked to HCV infection among HIV-positive men. However, the researchers found that fisting and use of recreational drugs became less linked to HCV infection over time. One possible explanation for this change, the Dutch scientists suggested, was that some MSM were becoming educated about behaviours that led to HCV infection and had reduced their risks. This possible explanation requires confirmation in a study designed to specifically assess HCV education and risk behaviours.
The researchers also analysed data gathered from 1,513 HIV-negative MSM from 2007 to 2010 to assess HCV infection. They found that rates of HCV infection in this population were low -- less than 1% (0.6%). There was no significant change in HCV infection rates over this time. Furthermore, the proportion of HCV infections among HIV-negative MSM was similar to that of the average HIV-negative citizen of Amsterdam who did not engage in high-risk behaviour.
Researchers in Australia who are experienced in studying the outbreak of HCV among HIV-positive men have reviewed data from many research projects in an attempt to put together explanations for the increase in HCV. According to their review and experience, there are several explanations, related to an interaction between behaviour, biology, germs and possibly some drugs. Here are some key factors followed by brief explanations:
Serosorting -- researchers have found that some men choose to have condomless sex with partners of the same perceived HIV status, a behaviour called serosorting. Among some MSM, this has led to increased high-risk behaviour "such as reduced condom use and increased traumatic sex leading to higher levels of STIs," stated the Australian researchers. Researchers in Berlin have also confirmed that serosorting leads to an increase in STIs. This can occur as people involved in serosorting generally think that the main germ of interest is HIV so they may not be as concerned about other STIs, including syphilis, gonorrhea, herpes, LGV (lymphogranuloma venereum) and human papilloma virus (HPV).
The wet lining of the anus, penis and rectum is delicate and relatively rich in mucous. The tissue lining these and other wet areas of the body are called mucosa. At least three published studies with MSM have found a link between damage to mucosa during sex and transmission of HCV, as follows:
A study done in the UK (comparing 60 cases of HCV infection to 130 people who did not have this infection) found that HCV infection was most strongly associated with engagement in group sex. Men who engaged in group sex were more likely to have condomless sex (insertive or receptive) and to engage in fisting (receptive or insertive). Exposure to multiple partners means an increased risk of exposure to germs.
A German study (comparing 34 cases of HCV infection to 67 people without HCV) identified several risk factors such as rectal trauma with bleeding, being fisted without gloves, group sex and nasally administered recreational drugs. The German researchers made this statement:
"We suggest that blood rather than semen is the critical medium. An insertive partner's fist (or penis), contaminated with blood, might serve as a vector for subsequent receptive partners in a group sex session, when condoms or gloves are either not applied or not changed for every new partner -- particularly when using a collective supply of lubricant. Lesions in both the ano-rectal mucosa -- from fisting, prolonged anal intercourse or rectal STIs -- could serve both as a portal of entry and as a source of infection."
A study in the U.S. (comparing 22 cases of HCV infection with 53 people who did not have HCV) generally found similar risks as the UK and German studies. However, in the U.S. study, two statistically significant risk factors were practising receptive anal intercourse without a condom when the insertive partner ejaculated and nasally administered recreational drugs.
Another U.S. study, done in the time before potent combination therapy for HIV (commonly called ART or HAART) was available, suggested that HCV could be transmitted sexually between MSM. Although sharing equipment for substance use was the strongest risk factor, having an enema/douching before receptive anal intercourse was also a risk factor for HCV infection.
One of the problems that bedevil researchers who study HCV transmission routes among MSM is the ability to be sure of the precise role that substance use plays. Studies of human behaviour tend to rely on self-reports by participants. As mentioned earlier, researchers suspect that some people do not disclose to researchers their behaviour about injecting street drugs. But even taking that into account, the intended effects of street drugs -- getting high, inducing feelings of euphoria and relaxation -- can cause people to temporarily lose their sense of judgement and control and to inadvertently engage in high-risk behaviour. However, as mentioned earlier, several studies have found a link between the use of nasally administered recreational drugs and an increased risk for becoming infected with HCV.
Regarding nasally administered drugs, in the previously mentioned German study, researchers made the following statement:
"A rolled banknote that is being circulated at a commercial sex party might be sufficient to expose consumers to HCV-contaminated blood."
Some recreational drugs used by MSM, such as methamphetamine (crystal meth), can dry mucous membranes (the delicate tissues lining the openings of the body, such as in the anus, nose and penis), increasing the risk for bleeding. Other drugs that are being used include cocaine, ecstasy, mephedrone, gamma-hydroxybutyric acid (GHB) or its pre-cursor gamma-butyrolactone (GBL), and ketamine (special K).
Some researchers think that HIV plays a role in the spread of HCV. It is possible that HIV, by weakening the immune system, may make some people more susceptible to HCV infection. It is also possible that HIV weakens the body's ability to control HCV in co-infected people, which might increase the amount of HCV in their blood. Certainly, one U.S. study has found that this is the case.
A study from France compared fluid samples from 120 HCV-infected men, 82 of whom were co-infected with HIV. Researchers confirmed the U.S. finding that HCV levels in the blood of co-infected men were greater than in men with HCV infection alone. Also, from time to time, they were more likely to detect HCV in the semen of some co-infected men compared to men who were infected with HCV alone.
Germs such as herpes, syphilis and LGV can cause sores, ulcers or lesions in delicate tissue inside the penis and anus (in addition to other parts of the body). These sores, ulcers or lesions could act as entry points for other germs such as HCV (and HIV). HCV experts have observed that the initial reports of HCV infection among some HIV-positive men noted that these men also had a history of LGV and syphilis. Other studies in France, Switzerland and Taiwan have all suggested that past or recent infection with syphilis can be linked to a future risk for acquiring HCV in MSM.
Reports from London, UK, as well as Tokyo, Japan, suggest that there may be an intersection of high-risk behaviours -- involving sex and substance use -- among some populations, including MSM. This may lead to the spread of both HIV and HCV.
As past experience with the nearly simultaneous outbreaks of LGV in Western Europe and North America has shown, outbreaks of sexually transmitted infections are not limited to one city or region but can and do spread to different continents. It is therefore possible that the outbreaks and behaviours being reported in London and Tokyo may be harbingers of what may be happening in other high-income countries.
All MSM can reduce their risk for acquiring HCV and other germs and can lead healthier lives by doing the following:
For people who suspect that they may have HCV infection, speaking to their doctor about testing is a good first step. Should this screening confirm HCV infection, asking a doctor about treatment options begins the process of managing this disease. Highly effective HCV treatments are being approved for use in Canada and other high-income countries.
INESSS -- Guides sur le traitement pharmacologique des ITSS
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