Introduction

One of the key components of the new Federal Initiative to Address HIV/AIDS in Canada is knowledge development, which will enhance our understanding of the HIV epidemic and inform the development of policies, programs, and interventions, such as new prevention technologies and therapies. The knowledge development component emphasizes the improvement of population-specific surveillance, including epidemiologic, socio-behavioural, ethnographic, and community-based research. The Surveillance and Risk Assessment Division, Centre for Infectious Disease Prevention and Control, has established I-Track, which is an enhanced surveillance system to track risk behaviours associated with HIV and hepatitis C virus (HCV) in people who inject drugs (IDU) in urban and semi-urban centres across Canada. It forms a part of the second-generation HIV surveillance as advocated by the World Health Organization and the Joint United Nations Programme on HIV/AIDS. Through this system, national and, to a certain extent, provincial and local trends in injecting and sexual risk behaviours among IDU can be assessed. Behavioural trend data obtained through the system will provide important information that can be triangulated with other data sources to assess the effects of prevention efforts and policies at the local, provincial, and national levels.

The surveillance system is being established in collaboration with local and provincial health departments, community-based organizations, and researchers. Within the Public Health Agency of Canada (PHAC), internal collaborations involve the Community Acquired Infections Division, the National HIV and Retrovirology Laboratory, and the HIV/AIDS Policy, Coordination and Programs Division.

Objectives

The objectives of national surveillance of HIV/HCV-associated risk behaviours among IDU in Canada are to describe changing patterns in drug injecting practices, HIV-and HCV-testing behaviours, and sexual behaviours among IDU. Depending on the availability of testing technologies, there are additional objectives:

• To describe changing patterns in the prevalence and incidence of HIV infections among IDU at the national and local level.
• To describe changing patterns in the prevalence and incidence of HCV infections among IDU at the national and local level.

The specimens collected under I-Track would also help in the study of HCV genotypes circulating in Canada.

Phase I of I-Track

In collaboration with provincial, regional, and local health authorities, community stakeholders, and researchers, PHAC has established a surveillance system of IDU, I-Track, at sentinel sites across Canada to track HIV-and hepatitis C-associated risk. First, a pilot study of the I-Track surveillance system was undertaken between October 2002 and August 2003 in Victoria, Regina, Sudbury, Toronto, and in Quebec and Ottawa through linkages made with SurvUDI. Since then, Phase I of the I-Track study was completed between October 2003 and May 2005 with the addition of Edmonton and Winnipeg.

This report presents the findings of the surveys undertaken between 2003 and 2005 at selected sites.

Results of the Phase I study

There were 3031 participants, recruited from seven sites: Edmonton (276), Quebec (including Ottawa) (1591), Regina (250), Sudbury (150), Toronto (260), Victoria (254), and Winnipeg

(250) in 2003-2005. The biological surveillance was undertaken through collection of dried blood specimens at all sites except in Quebec and Ottawa, where oral fluid specimen was collected. In the results and discussion, the results referred to as being from Quebec are the findings of surveys undertaken in Quebec and Ottawa.

Recruitment: Recruitment was mainly carried out at the needle exchange program (NEP) centres or their mobile and outreach services and through word-of-mouth. At some sites, promotion of the survey was done through flyers and posters that were displayed at prominent sites being frequented by IDU.

Demographics of the study population: The study population comprised 2092 (65.0%) males, 903 (34.1%) females, and 18 (0.7%) transgender males (information on gender was missing for 18 participants). The mean age of the study population was 36.7 years, and was higher for males

(37.8 years) than females (34.5 years). Nearly all (99%) of the study population was living in the city of recruitment. In terms of level of education, three-quarters of them had achieved high school or less. Nearly 42% of the study participants identified themselves as Aboriginal, and the majority of them were recruited from Regina, Edmonton, and Winnipeg, where 87%, 70%, and 70% respectively reported themselves as Aboriginal. Over half of the study population reported having stable housing (living in their own house or apartment or parent's/relative's house). Among the study participants 26% reported living in shelters and 27% on the street in the previous 6 months.

Drug use: Nearly a quarter of the study population (26.0%) reported injecting drugs every day, and 23.1% injected drugs once in a while, not every week. Among males one-quarter (25.5%) and among females nearly one-third (29.9%) had started to inject by the age of 16 years. The commonly injected drugs included cocaine, used by 77.5% of IDU, morphine (non-prescribed) by 45.9%, Dilaudid by 32.9%, crack by 31.9%, and heroin by 27.6%. The drugs injected varied by city: for example, in Regina, the majority of IDU reported Ritalin alone (or in combination with Talwin) as the most commonly injected drug, whereas in Victoria it was cocaine. In Toronto, Edmonton, and Winnipeg, a large proportion of IDU reported injecting crack most often, but its use was limited in other cities. People reported injecting mostly in their home (65.1%), but over a half (50.7%) reported injecting in public places also.

Seroprevalence of HIV and hepatitis C: The seroprevalence of HIV (average of seven sites) among study participants was 13.2% and varied by city: Edmonton 23.8%, Quebec (including Ottawa) 17.3%, Regina 2.9%, Toronto 7.6%, Sudbury 12.2%, Victoria 15.4%, and Winnipeg 13.1%. The seroprevalence of hepatitis C was 65.7% (average of seven sites) and varied by city: Edmonton 65.8%, Quebec (including Ottawa) 64.7%, Regina 63.7%, Toronto 67.1%, Sudbury 68.5%, Victoria 68.5%, and Winnipeg 61.8%. The HIV/HCV co-infection rate among the study participants was found to be 11.7% (average of seven sites).

Sharing of needles and injecting equipment: When asked about sharing needles and other injecting equipment such as cookers, water, cotton, filters etc. within the 6 months before participating in the study, 14.5% of the study population reported borrowing needles for injection. Needles were mostly borrowed from a close friend or from regular sex partners. In terms of other injection equipment, 30.9% of the study population had borrowed cookers, water, cotton, filters etc., mostly from a close friend or regular sex partners. Almost a third of the study participants (32.0%) reported passing on injecting equipment that they had used to others, and in comparison 18.2% of participants reported passing used needles to someone else.

Sexual behaviours: A significant proportion of the study population (20.0% of males and 11.5% of females reported not having had a sexual partner of the opposite sex) across the seven sites reported engaging in some kind of sexual activity during the preceding 6 months. Nearly one-third (32.1%) of female IDU reported having male client sex partners, 2.8% of the males had female client sex partners, and 6.2% of the males reported having had a male sexual partner within 6 months before the study. Condom use during penetrative sex was higher than during oral sex. Condom use during penetrative and oral sex was more infrequent with regular sex partners than with casual or client sex partners.

Testing behaviours: In terms of HIV/ HCV testing, 88.0% and 85.2% of the study population who responded to this question reported that they had ever been tested for HIV and HCV respectively. The proportions varied by site, over 90% of the study population in Toronto, Edmonton, and Quebec reporting that they had been tested for HIV, as compared with Regina, where only 80.0% reported ever having been tested. The proportion of those who reported having ever been tested for HCV was similar at all sites. When asked about testing for HIV in the 6 months before the study, overall 39.9% reported being tested in that period; the proportions varied at each site.

Conclusions

The results of the study indicate that the prevalence of HIV and HCV remains unacceptably high in IDU populations in Canada. Although the risky behaviours have shown a decline in the two phases of the I-Track survey, the possibility for the spread of HIV and HCV in these populations of IDU still exists. Ongoing monitoring of risk behaviours in IDU populations in urban and semi-urban locales is essential for program planning and evaluation, and I-Track is able to provide such information at the national and local levels. Given the rapidly changing and varied drug culture in different cities, prevention measures must be tailored to reflect these differences within each community. Services should be directed to those IDU whose test results are negative for HIV and HCV to help them remain negative, and to IDU whose results are positive for these two infections to provide them with the care and counselling needed to avoid further transmission of HIV and HCV.

Phase II of the survey has been completed in Victoria, Sudbury, and Kingston and is ongoing in Quebec and Ottawa. Efforts are under way to recruit additional sites to the surveillance system.

The need for behavioural surveillance among people who inject drugs in Canada

The Federal Initiative to Address HIV/AIDS in Canada commits the federal government to develop discrete approaches addressing the epidemic for eight specific target populations: people living with HIV/AIDS, gay men, people who inject drugs (IDU), Aboriginal people, prison inmates, youth, women and people from countries where HIV is endemic. One of the key components of the new Federal Initiative is knowledge development, which will enhance our understanding of the HIV epidemic and inform the development of policies, programs, and interventions, such as new prevention technologies and therapies. The knowledge development component emphasizes the improvement of population-specific surveillance, including epidemiologic, socio-behavioural, ethnographic, and community-based research. It advocates the establishment of sentinel surveillance programs for vulnerable populations, including those with co-infections and sexually transmitted infections, as appropriate. This is in line with the “Second Generation HIV Surveillance” being advocated by WHO and UNAIDS.¹ Second-generation surveillance emphasizes the importance of using behavioural data in addition to routine surveillance data to help explain changes in HIV incidence and prevalence, and as an early warning system for HIV spread. In addition, since behaviour change is the goal of most prevention programs, second-generation surveillance supports more extensive use of behavioural information to inform program design and to help evaluate programs.

In collaboration with provincial, regional and local health authorities, community stakeholders and researchers, PHAC has established a surveillance system of IDU, I-Track, at sentinel sites across Canada to track HIV-and hepatitis C-associated risk. First, a pilot study of the I-Track surveillance system was undertaken between October 2002 and August 2003 in Victoria, Regina, Sudbury, Toronto, and in Quebec and Ottawa through linkages made with the SurvUDI. Since then, Phase I of the I-Track study was completed between October 2003 and May 2005 with the addition of Edmonton and Winnipeg.

Background to IDU and HIV/HCV

IDU are at risk of acquiring HIV and other blood-borne infections, such as hepatitis C virus (HCV), through contaminated needles and unsafe sex practices The current national HIV estimates indicate that the proportion of new infections among IDU had decreased to 14% of all new infections in 2005 (350-650 of a total of 2,300-4,500 new infections).² A similar trend has occurred in the adult positive HIV tests reported to the Centre for Infectious Disease Prevention and Control (CIDPC), Public Health Agency of Canada (PHAC). Surveillance data as of December 31, 2005, indicate that in 2005, 19.5% of adult positive HIV tests reported to CIDPC were attributed to IDU, down from a peak of just over 33% in 1996 and 1997.³ Although the number of new HIV infections among IDU appears to be decreasing somewhat, the issue of HIV among IDU in Canada continues to be a serious problem that requires ongoing attention.

HIV prevalence at participating sites under I-Track (2002-2003) was quite variable, ranging from a low of 1.2% in Regina in 2002-2003 to a high of 19.6% at sites under SurvUDI (20032004).⁴ Available research indicates that HIV incidence and prevalence remain unacceptably high among Canadian IDU. HIV incidence in the ongoing SurvUDI study of people who inject drugs decreased from 5.1 per 100 person-years (PY) in 1995 to a range of 2.3–3.3 per 100 PY during 2001-04.⁵ Results from the Vancouver Injection Drug User Study (VIDUS) showed that HIV incidence was 1.5 per 100 PY in 2000, down from 10.3 in 1997 and 3.2 in 1999.⁶ Ongoing monitoring of the extent of HIV infection and trends in its spread among IDU from a variety of jurisdictions in Canada is needed given the worrisome levels of HIV infection that have been documented for this population.

The overall HCV prevalence rate for the I-Track study population in 2002-03 was 63.8% (average of four sites).⁷ The highest HCV prevalence rate was observed in Victoria at 79.3%, followed by Regina at 61.5%, Sudbury at 60.2%, and Toronto at 54.3%.⁷ Given the paucity of data on the extent of HCV among IDU, there is an urgent need to track HCV infection and trends in its spread among IDU from both large and small centres in Canada.

The pilot phase of I-Track^4,7 and other studies in Canada^5,8,9 have documented relatively high levels of needle sharing and multi-person use of other drug injecting paraphernalia, highlighting that the conditions exist for the spread of blood-borne viruses among networks of IDU. Ongoing monitoring of risk behaviours in IDU populations in urban and semi-urban locales would serve as an early warning system for HIV spread and would provide continuous data for prevention programming and evaluation.

Development of a system for surveillance of risk behaviours among IDU in Canada

Although several ongoing regional studies (VIDUS in Vancouver, SurvUDI in Quebec and Ottawa) collect risk behaviour data on IDU and a number of one-time cross-sectional surveys on risk-taking among IDU have been conducted (e.g. Regina Seroprevalence Study, RARE project Victoria, eastern project Cape Breton, Prince Albert seroprevalence study, etc.), it is challenging, if not impossible, to compare levels of risk behaviour between data sets. A national surveillance system that would track comparable HIV-and HCV-associated risk behaviour in IDU populations in urban and semi-urban centres across Canada would provide critical information for those involved in planning and evaluating the response to HIV/HCV among IDU. Through such a system, national and, to a certain extent, provincial and local trends in injecting and sexual risk behaviours could be assessed. Data on behavioural trends would also enhance existing national HIV/AIDS surveillance data and national incidence and prevalence estimates in monitoring the course of the HIV (and HCV) epidemic among IDU.

The development of a system for enhanced surveillance of risk behaviours among IDU in Canada (I-Track) that would contribute to achieving the above-mentioned benefits was proposed and developed by CIDPC. Partnerships were formed between PHAC, researchers, provincial/ local health authorities, and community-based organizations in Victoria, Edmonton, Regina, Winnipeg, Sudbury, and Toronto. In addition, linkages were developed with the ongoing SurvUDI study to implement the studies in Quebec and Ottawa. The selection of the sites to be included in the survey was a result of discussions among all stakeholders, including provincial and local governments, and was guided by HIV prevalence and incidence in different cities and the need to study the populations of IDU. The initial questionnaire was modified after a pilot phase and in consultation with the partners.

Objectives of surveillance of risk behaviours among IDU populations across Canada

The objectives of national surveillance of HIV/HCV-associated risk behaviours among IDU are as follows:

• To describe the changing patterns in drug injecting practices among IDU at the national and regional level
• To describe the changing patterns in HIV-and HCV-testing behaviour among IDU at the national and regional level
• To describe changing patterns in sexual risk behaviours among IDU at the national and regional level
• To describe changing patterns in the prevalence of HIV infections among IDU at the national and regional level
• To describe changing patterns in the prevalence of hepatitis C (HCV) infections among IDU at the national and regional level

Depending on the availability of valid tests, such as the detuned assay, additional objectives may include assessment of the incidence of HIV at the national and regional level. The specimens collected under I-Track would also help in the study of HCV genotypes circulating in Canada.

This report presents the findings of the surveys undertaken between 2003 and 2005 at selected sites.