Chapter 3: Population-specific HIV/AIDS status report: Gay, bisexual, two-spirit and other men who have sex with men - Status of HIV/AIDS

Chapter 3 – Status of HIV/AIDS among Gay, Bisexual, Two-Spirit and other Men who have Sex with Men

3.1 Introduction

This chapter summarizes the most recent epidemiology of HIV/AIDS among gay, bisexual, two-spirit and other men who have sex with men (MSM) in Canada. It begins with a broad picture of the epidemiology of HIV and AIDS cases attributable to the MSM exposure category in Canada compiled from routine HIV and AIDS surveillance data, findings from Phase 1 of M-Track^{Footnote 7} and data from the most recent national estimates of HIV in Canada. Specific data related to HIV/AIDS among MSM who use injection drugs, geographic and ethnic data related to the distribution of HIV/AIDS among MSM, and data on HIV viral strain and drug resistance are also presented. The chapter concludes with a brief discussion of HIV co-infections and other sexually transmitted and blood-borne infections (STBBIs) among MSM.

As discussed in Chapter 1, the epidemiological term MSM (men who have sex with men) is used in this chapter to denote a specific transmission route for HIV. As this chapter focuses on the epidemiology of HIV infection, MSM is the main term used for consistency with the original data sources, which examine behaviours rather than personal identity. However, the terms used in the original data sources are maintained for accuracy (e.g., M-Track is a survey of gay, bisexual and other MSM; therefore, the terminology in this chapter may change to reflect this source).

3.1.1 Types of Surveillance Data

The Public Health Agency of Canada uses the following three major types of epidemiological data to monitor HIV infections and AIDS cases in Canada: routine surveillance, enhanced surveillance (behavioural and biological survey data) and mathematical estimates. Each type of data has benefits and drawbacks. A complementary approach is therefore adopted to create a more comprehensive picture of the epidemiology of HIV/AIDS in Canada.

The Agency collects and analyzes routine surveillance data on positive HIV test reports and reported AIDS cases in Canada. Routine surveillance data are provided voluntarily to the Agency by the provinces and territories, consisting of positive HIV test reports and reported AIDS cases. Data on AIDS-related deaths are also collected. While a minimum set of data is provided for each positive HIV test report and AIDS case—usually age and sex—the amount of supplementary data provided varies, since not all jurisdictions report country of birth, race/ethnicity or exposure category.

Most positive HIV test reports and AIDS cases include one or more reported risk factors, such as sex with a male, sex with a female, injection drug use, or receipt of a blood transfusion. For the purpose of national reporting, positive HIV test reports and AIDS cases are assigned to a single identified exposure category based on the reported risk factors.

There are several limitations to routine surveillance data, including reporting delays, underreporting, missing information and undiagnosed HIV infections. As a result, routine surveillance data understate the magnitude of the HIV epidemic, and consequently, do not represent the total incidence and prevalence of HIV in Canada. Notably, national information on exposure categories of individuals who have tested positive for HIV is unavailable at the national level for Quebec, and can be incomplete for other jurisdictions. Notwithstanding these limitations, routine surveillance data provide important insights regarding the impact of HIV and AIDS on gay, bisexual, two-spirit and other men who have sex with men.

The Agency also monitors trends in HIV prevalence and associated risk behaviours in key vulnerable populations in Canada through enhanced (behavioural and biological) surveillance systems. Enhanced surveillance of HIV and other STBBIs combines behavioural and biological surveillance to help explain changes in the incidence and prevalence of HIV and other STBBIs in these specific populations. The objective of these enhanced HIV surveillance systems (known as the "Track" systems) is to describe changing patterns in the prevalence of HIV, as well as risk behaviour practices and testing patterns for HIV, hepatitis C (HCV) and other STBBIs in each respective population. The Agency has implemented an enhanced surveillance system focusing on injection drug users (IDU) called I-Track,^{Footnote 8} and another focusing on gay, bisexual and other MSM, called M-Track.^{Footnote 9} An enhanced surveillance system focusing on Aboriginal people in Canada, called A-Track, is currently being piloted.

M-Track was first implemented in 2005. It builds upon earlier local efforts and focuses on gay, bisexual, two-spirit and other MSM. M-Track aims to monitor trends in the occurrence of HIV, HCV and syphilis among MSM; and monitor changes in behaviours associated with the acquisition and transmission of these pathogens. (3)

Data available through routine and enhanced surveillance are supplemented with statistical modeling (i.e., estimating), which is used to estimate the number of HIV infections in Canada. The Agency estimates the prevalence and incidence of HIV and AIDS using combined statistical methods approximately every three years. The Agency is also responsible for reporting Canadian estimates of national HIV incidence and prevalence to UNAIDS. (4)

Finally, the Canadian HIV Strain and Drug Resistance Surveillance Program monitors the distribution of HIV subtypes and transmitted drug resistance among persons newly diagnosed with HIV in Canada. This type of data is used to detect different HIV subtypes circulating in Canada, inform vaccine development and treatment guidelines at the population level, and contribute to our understanding of HIV transmission, pathogenesis and progression to HIV-related diseases. (5)

3.2 Overview of the Epidemiology of HIV and AIDS Among MSM in Canada

Gay, bisexual, two-spirit, and other men who have sex with men in Canada continue to be disproportionately affected by HIV/AIDS. This group has accounted for the majority of HIV case reports with exposure information since HIV was first reported in Canada. While much has changed since the 1980s, MSM remains the most commonly reported exposure category among new HIV diagnoses, and HIV remains a significant health concern for gay, bisexual, two-spirit and other men who have sex with men. The following section provides an overview of the most recent epidemiological data available through national surveillance systems and estimates for the MSM exposure category.

3.2.1 Routine Surveillance

Through annual reports, the Agency provides an overview of the most recent epidemiological data available through national surveillance systems. It is important to note, as previously indicated, that exposure category data is incomplete in national HIV/AIDS reporting; the following information should be considered in the context of these data limitations and caution should be used when interpreting national trends over time.

Since HIV reporting began in Canada in 1985, a total of 74,162 positive HIV tests have been reported to the Agency up to December 31, 2011. Of these, 69,856 cases were among adults (≥15 years), with 37,133 (53.2%) reports including exposure category data. Among these cases, the MSM exposure category accounted for the largest proportion of positive HIV test reports in comparison to other exposure categories, with a cumulative total of 20,326 (54.7%). The MSM/IDU exposure category accounted for an additional 876 positive HIV test reports (2.4%). (6)

A significant drop in the proportion of new positive HIV tests attributed to MSM was observed between 1986 (89.7% of all HIV cases) and 1998 (36.0% of all HIV cases). An increase of 8.1% was observed between 2002 and 2011, and a ten-year high was reached in 2011 with 48.1% of positive HIV test reports among adults attributed to the MSM exposure category (see Figure 9).

Figure 9: Proportion of positive HIV test reports among adults (≥15 years) attributed to the MSM exposure category by year, 1985-2011 (n=20,326)

Source: (6)

In 2011, the MSM exposure category accounted for the highest number of positive HIV test reports as well, accounting for 531(48.1%) of all positive HIV tests reported among adults with known exposure category that year (see Figure 10). The MSM/IDU exposure category accounted for an additional 23 positive HIV test reports (2.1%) in 2011. (6)

Figure 10: Total number of positive HIV test reports among adults (≥15 years) with known exposure category*, MSM comparison, 2002-2011 (n=12,966)

Source: (6) Percentage based on total number minus reports for which exposure category was not reported or for which there was no identified risk (NIR).

As with HIV data, it is important to note that there are limitations to AIDS data available at the national level; the following information should be considered in the context of these data limitations and caution should be used when interpreting national trends over time.

From 1979 to December 31, 2011, 22,473 AIDS cases were reported to the Agency. Since 1979, among all reported adult (≥ 15 years) AIDS cases with known exposure category, the MSM category has accounted for the largest proportion of AIDS diagnoses, with a total of 13,616 cases or 67.2% (see Figure 11). (6) The MSM/IDU exposure category has accounted for an additional 5% (920 cases). (6)

Figure 11: Proportion (%) of reported AIDS cases among adults (≥15 years) attributed to the MSM exposure category, 1979-2011 (n=13,616)

Source: (6)

Overall, the number of new AIDS diagnoses reported to the Agency has decreased by over 56.4% over the past 10 years. (6) In 2011, 188 new AIDS cases were reported to the Agency. An exposure category was indicated for 95 of these cases, 29 of which (30.5%) were attributed to MSM. (6)

a) Geographic Distribution of the HIV/AIDS Epidemic in Canada: MSM

As discussed in Chapter 2, available demographic data suggest that, like the Canadian population as a whole, the majority of gay, bisexual, two-spirit and other men who have sex with men in Canada reside in Ontario, Quebec and British Columbia.

The proportion of cumulative positive HIV test reports attributed to the MSM and MSM-IDU exposure categories varies by province/territory. As mentioned previously, data on exposure categories of individuals who have tested positive for HIV is unavailable for Quebec. Among all positive HIV test reports attributed to the MSM and MSM-IDU exposure categories at the national levelFootnote 10, the majority of positive HIV tests have been reported in Ontario (MSM: 48.9%; MSM-IDU: 32.4%) and British Columbia (MSM: 31.0%; MSM-IDU: 42.4%) (see Figures 12 and 13). (6) This mirrors the location of Canada's urban centres and available demographic data regarding the distribution of gay and other men who have sex with men in Canada.

Figure 12: National distribution of positive HIV test reports attributed to the MSM exposure category among adults (≥15 years) by province/territory, 1985-2011 (n=20,326)

Figure 13: National distribution of positive HIV test reports attributed to the MSM-IDU exposure category among adults (≥15 years), by province/territory, 1985-2011 (n=876)

Source: (6)

Based on provincial/territorial surveillance data, it is also possible to assess the proportion of positive HIV test reports attributed to the MSM and MSM-IDU exposure category within each province and territory. Localized HIV epidemics may be concentrated in different populations and driven by different risk behaviours^{Footnote 11}. The provinces and territories who report a majority of positive HIV test reports attributed to the MSM exposure category are Ontario (64.4%), Nova Scotia (62.1%), British Columbia (53.0%), Newfoundland (50.8%), and New Brunswick (50.5%). For the MSM-IDU exposure category, the largest proportions are found in New Brunswick (5.7%) and Yukon (5.6%). In all other provinces and territories, the proportion ranges from 0% to 4.0% (see Figure 14).

Figure 14: Proportion and number of positive HIV test reports attributed to MSM and MSM-IDU exposure categories among adults (≥15 years) within each province/territory, 1985-2011

Source: (6)

b) Age

It is important to note the latent nature of HIV infection, which can go undetected for years. This may delay an individual's decision to get tested; as a result, the age at the time of diagnosis does not necessarily reflect the age at which HIV was contracted.

HIV surveillance data show that the number of positive test reports attributed to the MSM exposure category varies widely by age group, though tends to remain consistent year-to-year. The highest number of cases is generally reported among those in the 20 to 49 year age groups. In 2011, those aged 20-29 years (147 cases), 30 to 39 years (167 cases) and 40-49 years (141 cases) accounted for 86% of all positive HIV test reports attributed to MSM. In 2011 the highest number of positive HIV test reports in the MSM-IDU exposure category were reported for the 20 to 29 and 30 to 39 year age groups (9 cases each), followed by those aged 40 to 49 years (4 cases) (see Figure 15). (6)

Figure 15: Number of positive HIV test reports attributed to the MSM (n=531) and MSM-IDU (n=23) exposure categories, by age group, 2011

Source: (6)

Cumulative AIDS data from 1979 to December 2011 show that among 13,616 cases attributed to the MSM exposure category, the highest proportion were reported among those aged 30 to 44 years (8,585 or 63.1%). For the same time period, among 919 cases attributed to the MSM-IDU exposure category, the largest proportions of cases were seen among those aged 30-34 years (235 cases), 35-39 years (184 cases) and 25-29 years (181 cases) (see Figure 16).

Figure 16: Proportion of reported AIDS cases attributed to the MSM (n=13,616) and MSM-IDU (n=919) exposure categories, by age group, 1979-2011

Source: (6)

c) Distribution of Race/Ethnicity Among Positive HIV Test Reports and Reported AIDS Cases

As described in Section 3.1.1, exposure category information is used in routine HIV/AIDS surveillance to monitor the routes of HIV transmission. Information collected on race and ethnicity through routine surveillance, when coupled with exposure category information, helps further describe HIV and AIDS in Canada. Collection of race and ethnicity data in Canada began in 1998, however, as with exposure category data, collection and submission of this information varies by jurisdiction. Up to 2011, 81.8% of all positive HIV test reports were missing information on race and ethnicity, therefore the following information should be considered in the context of these data limitations and caution should be used when interpreting national trends over time.

Cumulatively (from January 1998 to December 2011), among positive HIV test reports attributed to the MSM exposure category, the majority (78.0%) were among people who identified as White. The remaining positive HIV test reports attributed to the MSM exposure category were among the following racial/ethnic groups: Asian (7.4%), Aboriginal (5.2%), Latin American (5.2%), South Asian/West Asian/Arab (1.8%), Black (1.6%) and Other (0.8%). (6)

Exposure category tends to vary by racial/ethnic category. Between 1998 and 2011, among all positive HIV test reports which included racial/ethnic data, the MSM exposure category was most frequently reported among Latin American (69.3%), Asian (58.4%) and White (46.5%) categories (Figure 17). The Other, White and Aboriginal racial/ethnic categories experienced the highest proportions of cases attributed to MSM-IDU, at 4.3%, 3.5% and 3.2%, respectively.

Figure 17: Proportion of positive HIV test reports among adults (≥15 years), by race/ethnicity and exposure category, 1998-2011 (n=10,039)

Source: (6)

Since 1979, among adult AIDS cases attributed to MSM exposure, 91.7% were identified as White. No other racial or ethnic group has accounted for more than 2.0% of MSM-related exposure. In the MSM/IDU category, Whites accounted for 88.7% of all adult cases with race/ethnicity information, while 7.2% were identified as Aboriginal.

d) Two-Spirit, Gay, Bisexual and Other Aboriginal MSM

From January 1998 to December 2011, 2,647 positive HIV tests have been reported among Aboriginal people, 6.4% of which have been attributed to the MSM exposure category. MSM is the third most commonly reported exposure category among Aboriginal people after injection drug use (IDU), which accounted for 59.8% of positive HIV test reports, and heterosexual contact, which accounted for 29.4%. The MSM-IDU exposure category accounted for an additional 3.2% of all positive HIV test reports attributed to Aboriginal adults during this time period. (6)

The reported AIDS case data present a similar picture. From November 1998 to December 2011, there were 503 cases of AIDS reported among Aboriginal adults. The highest proportion of cases was attributed to the IDU exposure category (58.6%). In contrast, the MSM and MSM-IDU exposure categories accounted for 10.3% and 4.8%, respectively.

3.3 Enhanced (Biological and Behavioural) Surveillance/Population-specific Surveillance Data: a Snapshot of M-Track Phase 1 Data

M-Track is an enhanced surveillance system for HIV and other STBBIs among gay, bisexual and other MSM in Canada and is conducted through periodic, cross-sectional surveys administered at selected sentinel sites across the country. Participants are primarily recruited using venue-based sampling methods. M-Track participation is voluntary, anonymous, and requires informed consent. Information on demographics, sexual behaviours, drug use, HIV and other STBBI testing, and attitudes towards HIV, HCV and other STBBIs is collected via a self-administered national core questionnaire.^{Footnote 13}

To date, six sites have participated in M-Track across Canada. Phase 1 of M-Track was first implemented in Montréal in 2005. Between 2006 and 2007, four additional sites joined M-Track: Ottawa, Toronto, Winnipeg and Victoria. The Vancouver site was the most recent location to implement M-Track, joining Phase 2, which began in 2008 and ended in 2010. Montréal also participated in Phase 2 of M-Track. Some sites opted to locally brand the M-Track survey, which included a local survey name—the survey in Ottawa and Toronto is called Lambda, in Montréal Argus, and in Vancouver, ManCount. The four provinces that have participated in M-Track to date account for almost 90% of all HIV-positive tests reported to the Agency since reporting began in 1985.

The following are selected data from Phase 1 of M-Track.

Over 4,500 men participated in Phase 1 of M-Track between 2005 and 2007 across the five participating city-sites: Montréal, Ottawa, Toronto, Winnipeg and Victoria. Most men who participated in M-Track reported having been tested for HIV (86%) at least once. Of men who reported that their most recent HIV test was negative, a large proportion had been tested for HIV in the two years preceding survey participation (75%). (3)

Among participants who provided a biological sample^{Footnote 14} of sufficient quantity for testing, and who completed a questionnaire, the prevalence of HIV was 15.1% (Figure 18). Of the men whose biological sample tested positive for HIV, 19% were unaware of their HIV-positive status. (3) In the United States, by comparison, 44% of HIV-positive MSM who participated in the National HIV Behavioral Surveillance system (NHBS) were unaware of their HIV infection. (8) The M-Track figure compares favourably with the US, and is lower than the overall estimated percentage of Canadians unaware of their HIV-positive status (26%). (9) Nonetheless, it indicates that 91 M-Track participants were unaware of their HIV-positive status.

As the M-Track surveillance system is anonymous, respondents did not receive the results of their biological tests. However, participants were encouraged to seek testing for HIV and other STBBIs via local clinics or physicians. Local contact information for healthcare providers and testing facilities was available at each site and used by research assistants to make appropriate referrals.

Figure 18: Prevalence (%) of HIV among MSM who participated in Phase 1 of M-Track, 2005-2007 (n=3,309^a)

^aOf 4,793 men who completed a questionnaire in Phase 1 of M-Track, 3,309 provided a dried blood sample (DBS) of sufficient quantity for HIV testing.

As noted above, the Track surveillance systems primarily use venue-based sampling methods to overcome some of the inherent difficulties in accessing hard-to-reach populations. As a result, the surveillance findings are not representative of all MSM in Canada. Underreporting of some risk behaviours may occur because of social desirability biases.

For more detailed information on Phase 1 M-Track results, please refer to the Public Health Agency of Canada's report M-Track: Enhanced surveillance of HIV, sexually transmitted and blood-borne infections, and associated risk behaviours among men who have sex with men in Canada. (10)

3.4 National Estimates of HIV Incidence and Prevalence

3.4.1 National Estimates of HIV Prevalence in 2011

The most recent national estimates indicate that gay and other MSM continue to be the population most affected by HIV, with an estimated 46.7% (33,300) of all prevalent cases in 2011 attributed to the MSM exposure category. This estimated overall proportion was similar to the estimated proportion in 2008 (46.9%). (8; 91) In addition, the combined MSM-IDU exposure category was estimated to represent an additional 3% (2160) of prevalent cases in Canada in 2011, while the estimated rate for 2008 was 3.2%. (9)

Of the estimated 71,300 people living with HIV in Canada in 2011, 25% (17,980, ranged of 14,500-21,500) were unaware of their HIV infection. This represents a slight decrease from 2008, when it was estimated that 26% of people living with HIV in Canada were unaware of their HIV infection. (91) However, fewer HIV-positive individuals in the MSM exposure category were estimated to be unaware of their HIV infection relative to all people living with HIV in Canada (20% in the MSM exposure category versus 25% of all persons living with HIV). This translated into an estimated 6,700 (5,100-8,300) people living with HIV in the MSM exposure category who were unaware of their HIV-positive status. (9) By comparison, a higher proportion of HIV-infected people in the IDU exposure category (24%) and in the heterosexual exposure category (34%; endemic and non-endemic combined) were estimated to be unaware of their HIV infection. (9)

3.4.2 National Estimates of HIV Incidence in 2011

Gay and other MSM continued to account for the highest proportion of estimated new HIV infections in 2011 (46.6%, or 1,480 cases attributed to the MSM exposure category, range of 1,060-1,900). This was slightly higher than the estimated 44.1% of new infections attributed to the MSM exposure category in 2008. (91) The combined MSM-IDU exposure category represented an additional 2.5% (80 cases, range of 50-110) of new HIV infections in 2011. (9)

Over time, the estimated new HIV infections among gay and other MSM has varied greatly. In the early stages of the epidemic, the majority of new infections were attributed to the MSM exposure category. This trend reached its peak in 1984-85. New infections attributed to the MSM exposure category then declined sharply until 1996, increased again between 1999 and 2005, and have essentially been stable since 2005. Figure 19 illustrates the trends in estimated numbers of new HIV infections in Canada across selected exposure categories. (11)

Figure 19: Estimated number of incident HIV infections per year in Canada by exposure category (range of uncertainty omitted)

Source: (11)

3.5 Viral Strain and Drug Resistance

HIV viral strain and subtype surveillance is important for understanding the distribution of HIV subtypes in Canada. This ensures that HIV tests continue to reliably detect all strains and subtypes. The surveillance data inform vaccine development, enable assessment of genetic markers of drug resistance, and inform our understanding of HIV transmission, pathogenesis and progression to AIDS.

Results from the Public Health Agency of Canada's national HIV Strain and Drug Resistance program indicate that the viral strain HIV-1 B predominates among men infected through having sex with men. Of specimens received by the HIV Strain and Drug Resistance program from 1984 to 2005, 97.7% (785 of 803) of all HIV infections attributed to the MSM exposure category were HIV-1 Subtype B. Cases attributed to MSM-IDU are also primarily infected with Subtype B, with 92.3% (84 of 91) of specimens showing this viral strain. When comparing across exposure categories, data suggest non-B subtypes of HIV-1 are more prevalent in individuals infected by heterosexual sex (including those who come from HIV-endemic countries). (5)

Antiretroviral therapies (ARVs) have led to simplified treatment regimes and reduced mortality rates from AIDS-defining illnesses for many people living with HIV/AIDS (PHAs) in Canada. There are concerns, however, that the increased and widespread use of ARVs and a growing number of treatment failures may lead to the transmission of drug-resistant strains of HIV. Overall, the prevalence of primary drug resistance in treatment-naïve HIV-positive individuals was 8.9% among specimens received by the national Strain and Drug Resistance program for the years 1996-2005. The prevalence of multi-drug resistant (resistant to more than two classes of ARVs) HIV was 1.4% among specimens for the same time period. (5) Specimens attributed to the MSM exposure category exhibited a primary drug resistance prevalence of 9.2% for the years 1996-2005, while specimens attributed to the MSM-IDU exposure category exhibited a primary drug resistance prevalence of 8.6% during the same time period. (5)

3.6 HIV Co-infections

HIV co-infection with pathogens such as tuberculosis and sexually transmitted and blood-borne infections (STBBIs) presents specific challenges for the health of co-infected individuals and poses additional risk of HIV transmission on a population level.

Data are limited on co-infections and trends in STBBIs other than HIV among MSM at the national level. Based on the data that are available, HIV co-infections represent a significant health burden among MSM, and evidence from other developed countries points to the common occurrence of HIV co-infection with other STIs in this population. (12-17) Data on the prevalence of STIs among MSM come from enhanced surveillance activities and targeted epidemiological studies. Co-infections involving HIV and other STIs have significant implications for disease progression, treatment and care. However, there is limited evidence in Canada on viral hepatitis and tuberculosis from surveillance systems and targeted research studies specific to MSM.

3.6.1 Sexually Transmitted Infections

Sexually transmitted infections (STIs) are associated with an increased risk of acquiring and transmitting HIV. (12;18-27) Similar transmission modes and risk behaviours for HIV and STIs, as well as several biological factors related to STI infection, increase one's susceptibility to infection. (18) STIs such as gonorrhea, chlamydia, herpes simplex virus (HSV) and syphilis can cause genital lesions and inflammation, thereby increasing the risk of HIV transmission during sex. (18;25;28) STIs also elicit immune responses, causing local increases in immune cells which are targets for HIV. (18;23;25) Co-infection with HIV and another STI can also increase the risk of transmitting HIV to a sero-discordant partner. (18;23;29-32)

The relationship between HIV and other STIs extends beyond transmission risks. Co-infection with HIV and another STI can accelerate the progression of HIV and have significant effects on the disease course of the co-existing STI. (12;18;23;26;32;33) For example, an individual infected with HIV and syphilis may be at greater risk of developing neurosyphilis. (34;35) Syphilis co-infection is also associated with an increase in HIV viral load and a decrease in CD4 cell count, markers of disease progression for HIV-positive individuals. (29) HIV and other STI co-infections thus create a significant burden on affected communities, and can collectively increase the burden of each individual infection.

Although knowledge of the relationship between HIV and other STIs has evolved, further research is needed to better understand the synergistic relationship between STIs and HIV. (19;25) Other influences, such as IDU or social determinants of health (e.g., low income, overcrowded living conditions, poor access to health care) can put MSM at risk for other blood-borne infections such as hepatitis B and hepatitis C.

a) Syphilis

Nationally collected data on syphilis co-infection in MSM with HIV are not available. However, data collected on syphilis outbreaks across Canada have identified MSM as the primary community affected. (32;36;37) In Ontario, having a same-sex sexual partner was the most frequently reported risk factor for infectious syphilis among men, accounting for 84% of cases (532 of 630) in 2009. (38) MSM also account for over 90% of cases of infectious syphilis in Quebec. (39) In British Columbia, 66.2% of infectious syphilis cases were among MSM in 2009. (40) Over one third (37.0%) of syphilis cases in the province were among MSM living with HIV. (40)

M-Track data are also available on HIV and syphilis co-seropositivity. When describing the biological results for hepatitis C and syphilis from M-Track, the term co-seropositivity is used instead of infection because the dried blood sample (DBS) tests can only detect lifetime prevalence and cannot distinguish between past and current syphilis infections (i.e., antibodies to a past or present infection). Among Phase 1 M-Track participants who provided a biological sample of sufficient quantity for testing for both HIV and syphilis, 12% were seropositive for only HIV, 3.4% were seropositive for only syphilis, and an additional 2.9% were seropositive for both HIV and syphilis (i.e., HIV/syphilis co-seropositive). (10)

Although data identifying same-sex sexual behaviour are not available through the routine surveillance of STIs in Canada, male-to-female rate ratios can also be used as a surrogate for trends in male-to-male transmission of STIs. An increase in the male-to-female rate ratio for infectious syphilis (8:1 in 2004 compared to 1.3:1 in 1997) suggests increased transmission among MSM. (41) Two recent US-based studies have also found that MSM are at higher risk of HIV and syphilis co-infection. (42;43)

b) Gonorrhea

Canadian data on HIV/gonorrhea co-infection are not readily available. However, international studies show that rectal gonorrhea infection is associated with higher rates of HIV co-infection and seroconversion over time. (44-48) In addition, a meta-analysis of the effect of genital tract infections on HIV-1 shedding in the genital tract found evidence of increased HIV-1 shedding in HIV-positive persons co-infected with gonorrhoea or chlamydia. (49)

c) Chlamydia

Canadian data on HIV-chlamydia co-infection are not readily available. However, international studies have found evidence of increased HIV viral shedding in the semen of HIV-positive individuals co-infected with chlamydia. (49-51)

d) Lymphogranuloma Venereum

Until recently, the STI lymphogranuloma venereum (LGV) was rare in industrialized countries. However, outbreaks in MSM communities have been observed in Europe, the US, and Canada. All Canadian cases of LGV have been among males, with the majority reporting recent sexual activity with one or more male partners. A recent systematic international review found a significant association between LGV and HIV among MSM, with a prevalence of HIV among MSM with LGV ranging from 67% to 100%. (52) In Canada in 2009, HIV co-infection was reported in 72.4% (42 out of 58) of LGV cases among males with information available on HIV infection status. (53)

e) Human Papillomavirus

International data suggest that the prevalence of anal human papillomavirus (HPV) is significantly higher among MSM (54) with HIV-infected MSM having rates of infection upwards of 95%. (55-58) HPV has been associated with the development of anal cancer. (59-61)

In Canada, the Toronto Research for Anal Cancer Evaluation (TRACE) study of 224 HIV-positive MSM found HPV among 93% of participants. (62) Some data on HPV are also available from the Vancouver M-Track site (locally branded as ManCount). As a site-specific initiative, ManCount asked a subsample of men to participate in an additional study, unique to Vancouver, by providing an anal swab for HPV screening, as well as chlamydia, gonorrhoea and anal cancer. Of the samples that were adequate for analysis (approximately two thirds of 239 swabs), 62% were positive for HPV. (63)

3.6.2 Viral Hepatitis

a) Hepatitis A

Hepatitis A is an acute viral liver infection, transmitted person to person via the fecal/oral route, through ingesting contaminated food or water, or direct contact (including sexual contact) with an infected person. (64) The prevalence of hepatitis A among MSM has been reported to be significantly higher in European studies (64) and outbreaks have also been reported in the US and Australia. (64;65) Evidence on the impact of hepatitis A infection on HIV is mixed. Some studies suggest no impact, (64;66) while others suggest HIV infection may prolong hepatitis A infection and increase the likelihood that hepatitis A becomes symptomatic and that it may increase HIV viral load. (64;67)

b) Hepatitis B

In most Western countries where hepatitis B prevalence is low, including Canada, hepatitis B transmission is mainly restricted to certain risk groups, such as people who use injection drugs, sex workers and MSM. In Canada, sexual transmission, especially between men, is the main route of hepatitis B infection.

Despite the availability of safe and effective vaccines, many MSM have not been adequately vaccinated against hepatitis B. From 2005-2010, of 262 acute hepatitis B patients in Canada who were interviewed as part of the Enhanced Hepatitis Strain Surveillance System, 9.9% (26 of 262) reported having a history of MSM activity in the six months before the onset of illness. (68) Another study indicated that approximately 21.9% of all new hepatitis B infections in Vancouver are among MSM. (69)

As a consequence of shared modes of transmission, co-infection with hepatitis B among persons living with HIV is relatively common. Among men who are infected with hepatitis B, 6%-10% are co-infected with HIV. (70) Hepatitis B progresses more quickly in HIV-positive patients. Episodes of hepatitis B activation are more frequent, cirrhosis of the liver occurs more rapidly and hepatocellular carcinoma is more frequent than in those who are only infected with hepatitis B. (71) Moreover, liver-related mortality among patients co-infected with hepatitis B and HIV is 14 times greater than that of patients infected with only one of the viruses. (70;71) Hepatitis B treatment options are also limited, and treatment outcomes are negatively influenced when a patient is co-infected with HIV. Monotherapy for both HIV and hepatitis B is inappropriate because of the high possibility of resistance. (71)

c) Hepatitis C

Other STI co-infections with HIV also impact disease progression, treatment, management and transmission. Canadian data on hepatitis C (HCV) co-infections with HIV among MSM are currently limited.

The primary risk factor for HCV transmission is exposure to infected blood, such as through the use of contaminated equipment for IDU, which accounts for the majority of such infections nationally. (72;73)

Sexual transmission of HCV is controversial; some consider sexual transmission rare. (74;75) Others have reported evidence supporting the sexual transmission of HCV and consider it a risk for MSM. (76-80) From 2002-2007, of 8,389 male HCV patients in Canada who were interviewed as part of the Enhanced Hepatitis Strain Surveillance System, 707 (8%) reported having a lifetime history of MSM activity. MSM-IDU, with their potential for sexual and percutaneous (i.e., through IDU) exposure, are a specific population at risk for HCV infection, as well as co-infection with HIV due to the common transmission routes of these infections. (79)

HIV and HCV co-infection impacts the health of those affected and presents challenges for care providers. HCV co-infection with HIV is associated with higher rates of liver disease, (81;82) which is negatively correlated with CD4 counts. (83) With high rates of HIV and HCV co-infection and longer life expectancy among HIV-infected individuals, HCV has become a leading cause of morbidity and mortality among the HIV-positive population, a trend that is expected to continue as HIV treatments improve. (84-86) Care and support services for co-infected individuals are important for improving and maintaining health because of treatment-related drug interactions and toxicities. (84)

Agency data on MSM HIV-HCV co-infection are also unavailable; however, data are available on co-seropositivity.Footnote 15 Data from Phase 1 of M-Track indicate that, among men who provided biological samples of sufficient quantity for testing for both HIV and HCV, 12.9% were HIV seropositive only, 3.1% were HCV seropositive only, and an additional 2.2% were HIV/HCV co-seropositive. (10)

3.6.3 Tuberculosis

There is little domestic or international data available about TB and HIV co-infection among MSM.

By 2007 only 12% of TB patients in the general population were tested for HIV among the 202 countries that report to the WHO monitoring system. (87) In Canada there has been a slow but steady increase in the number of reported TB cases for which HIV status was also reported. In 2009, the HIV status of 39% of all TB cases was reported, up from 16% in 2000. Of the cases for which HIV status was reported, 9.9% were positive; however, this does not necessarily reflect the prevalence of HIV among TB cases, as a number of other risk factors may have led to being tested for HIV. As a result, the prevalence of HIV among TB cases is estimated at between 3.9% and 9.9%, which should be interpreted with caution. (88) Enhanced TB recording and reporting for HIV-infected individuals and HIV reporting for TB-infected individuals is being encouraged.

Latent TB infection is an important HIV co-infection concern. It is estimated that one third of the general population is infected with dormant TB and that between 5% and 10% of individuals with latent infection will progress to active disease at some point in their lives. However, among those co-infected with HIV and TB, there is a 10% annual risk of progression to active TB disease. (89) As with other co-infections, treatment of HIV and TB co-infection presents challenges for healthcare providers due to the need to manage multiple treatments. (90)

3.7 Conclusion

Notwithstanding certain limitations regarding the collection and reporting of data, important conclusions can be drawn based on the information presented in this chapter. It is clear that, since the beginning of the epidemic, gay and other men who have sex with men have been, and continue to be, the population most affected by HIV and AIDS in Canada. This population accounts for the highest proportion of both new and prevalent infections, as well as reported AIDS cases. This fact, combined with the fact that new infections continue to occur among MSM, points to the need for a sustained and renewed approach to prevention, testing, diagnosis, care and support among gay and other men who have sex with men.

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