A new HIV surveillance system that is tracking risk behaviours among injection drug users in cities across Canada will yield crucial data to help national, regional and local health authorities plan prevention efforts for HIV and related infections, such as sexually transmitted infections (STIs) and hepatitis C.

«Risk behaviour is accepted around the world as another type of information you need to properly monitor prevention programs,” explains Dr. Chris Archibald, Director of the Public Health Agency of Canada's (PHAC) Surveillance and Risk Assessment Division. «Because it involves gathering behaviour information, in addition to information on a person's infection status, this is often referred to as ‘second generation' surveillance.”

I-Track was launched in the fall of 2002 to monitor risk behaviours in cities that have a particularly serious injection drug use (IDU) problem. Sites in Victoria, Sudbury, Toronto, Winnipeg, Regina, Edmonton, Ottawa and across the province of Quebec are currently participating in the system (the Ottawa and Quebec locations are participating through an agreement with the ongoing SurvUDI study). Halifax and two cities in Ontario - Kingston and Thunder Bay - are being considered as new I-Track sites. Vancouver is doing its own study and is not currently part of the I-Track surveillance system.

«We do periodical surveys of IDU populations in the different cities to track trends in risk behaviours and changes in the HIV epidemic,” explains Dr. Yogesh Choudhri, a consultant working on the project for PHAC. «The surveillance system will provide critical information for those involved in planning and evaluating the response to HIV, STIs and hepatitis C by allowing us to assess national and, to a certain extent, provincial and local trends in risk behaviours.”

In addition to answering questions about their behaviours, respondents are asked to provide blood samples, which are tested for HIV, hepatitis C and other infections.

«We now have three years of data, and our big focus at this time is on getting the data out to people who need it, like managers of needle exchange programs,” says Dr. Choudhri. «We need to structure and present the data so that it feeds into their programs.”

The surveillance system is a collaborative effort between PHAC, provincial ministries of Health, regional and local health authorities, researchers and community stakeholders in the sentinel sites. For its part, PHAC provides financial and technical support, including funding for the surveys, blood sample analysis, and data input and analysis at the national level. The provinces also contribute funding, and local health authorities provide office space and personnel to manage the surveys.

Dr. Murray Fyfe, a medical health officer with the Vancouver Island Health Authority, is one of many individuals working to implement the surveillance system at the street level.

«Our role is to work with PHAC and with community agencies to conduct the I-Track study among a sample of the injection drug using population in Victoria,” says Dr. Fyfe. «During Phase I and Phase II, three interviewees were contracted to do the work, and about 250 injection drug users were interviewed. They were generally quite receptive to being included in the study and quite accepting of the questions being asked.”

The data gathered in the first two phases of the study will be of tremendous value to organizations that provide services to injection drug users in the Greater Victoria area.

«Hopefully this will give us an accurate snapshot of blood-borne pathogens and the behaviours that put this community at risk of HIV and hepatitis C,” says Dr. Fyfe. «At the local level, this data will help shape our programming and the services we provide to this population.”

Dr. Fyfe notes that the Vancouver Island Health Authority is already looking forward to participating in additional cycles of the survey, probably at two-year intervals. «This is a great example of the provinces and municipalities coming together with the federal government to create a truly national system,” says PHAC's Dr. Archibald. «A second generation surveillance system has also been established for men who have sex with men, and we hope to expand this approach into other at-risk population groups in the future.”