HIV in Canada Among Persons from Countries where HIV is Endemic

Centre for Infectious Disease Prevention and Control

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Immigration and HIV/AIDS Surveillance

On January 15, 2002, Citizenship and Immigration Canada (CIC) initiated routine HIV testing for all applicants who require an Immigration Medical Examination (IME) and are 15 years and over, as well as for those children who have received blood or blood products, have a known HIV-positive mother or are potential adoptees. In June 2002, the Immigration and Refugee Protection Act (IRPA) was implemented, requiring that applicants be assessed for inadmissibility on the basis of health care needs. Certain groups, such as refugees and family-class immigrants, are exempted from the Act. Further information on this legislation is available on the CIC Web site (www.cic.gc.ca).

Between January 15, 2002 and December 31, 2004, 1,474 applicants tested positive for HIV during their IME.^*** Of these 1,474 applicants:

• 918 were identified via testing in Canada, and 556 were identified outside of Canada; and,
• 981 (67%) were born in Africa and the Middle East, 334 (23%) in the Americas, 109 (7%) in Asia and 50 (3%) in Europe.

For HIV screening conducted in Canada, most provinces and territories handle positive HIV test reports in the same manner as all other positive HIV tests and included them in their HIV report to CIDPC. The 918 positive HIV test reports identified in Canada represent 12% of the 7,522 positive HIV tests reported to CIDPC during the above-mentioned time period.

HIV/AIDS Incidence and Prevalence Estimates Among Persons from Countries where HIV is Endemic

National HIV surveillance data capture only those who are tested, whose HIV infection is diagnosed and whose positive test results are reported to CIDPC. As a result, surveillance data do not describe the full scope of the epidemic. Calculations using national surveillance data supplemented by other data sources and analytic methods are carried out to estimate the total number of people living with HIV (prevalence) and the number newly infected with HIV (incidence).

CIDPC has estimated the number of Canadians living with HIV, including those living with AIDS (prevalence), to be 56,000 (46,000 - 66,000) in 2002.²³ Of these, it was further estimated that there were approximately 3,700 to 5,700 prevalent HIV infections among persons from HIV-endemic countries within the heterosexual exposure category, representing 7 to 10% of all prevalent infections in Canada.

It has also been estimated that 250 to 450 of the estimated 2,800 - 5,200 new HIV infections diagnosed in Canada in 2002 (representing 6 to 12% of all new infections in Canada),²³ were among persons belonging to the HIV-endemic exposure subcategory. It is important to consider that these incident infections include a mix of infections that were acquired in a person's country of origin as well as infections that were acquired in Canada. Remis & Merid¹³ have undertaken a modelling exercise to try to differentiate the sources of infection in Ontario, and their results suggest that 20 - 60% of new infections in the HIV-endemic group in Ontario occurred after arrival in Canada. Distinguishing between HIV infections acquired abroad or within Canada is important not only for accurately measuring Canadian incidence, but also for more effectively guiding prevention and care programs, particularly when considered with demographic characteristics such as age and gender.

When these national incidence and prevalence estimates are compared to data from the 2001 Census, it is clear that persons from countries where HIV is endemic are over-represented in Canada's HIV epidemic. In 2001, approximately 1.5% of the Canadian population was born in a country where HIV is endemic,³ yet this group accounted for an estimated 7 - 10% of prevalent HIV infections and 6 - 12% of all new infections in 2002.

As previously mentioned, the estimates noted above pertain only to HIV-infected persons from countries where HIV is endemic within the Heterosexual Contact exposure category. Persons from HIV-endemic countries in other exposure categories are not included and the number of such persons is likely not insignificant. For example, using mathematical modelling, Remis & Merid¹³ estimated that there were 2,627 persons from HIV-endemic regions (1,366 from sub-Saharan Africa and 1,261 from the Caribbean) living with HIV infection and residing in Ontario in 2002. This number comprises 11% of the estimated 23,563 HIV-infected people in Ontario, which is much higher than the 2.6% of the Ontario population that is from a country where HIV is endemic. In addition, Remis and Merid¹³ estimated that at least 400 or more of these HIV-infected 2,627 persons were from the MSM exposure category.

In 1999, Adrien et al.²⁴ estimated the prevalence of HIV infection among Montrealers of Haitian origin in a clinic-based epidemiological study of 5,039 persons aged 15 to 49 born in Haiti or with at least one parent born in Haiti. Overall, the HIV prevalence in this population was 1.3% (1.6% in men and 1.1% in women), and was lower among those born in, or who were long-term residents of, Canada. These data further illustrate the overrepresentation of persons from HIV-endemic countries in Canada's HIV epidemic.

Comment

Limitations

This report has summarized HIV and AIDS surveillance data for persons belonging to the HIV-endemic exposure subcategory of the broader Heterosexual Category. It should be noted that due to a number of limitations as mentioned above, surveillance data underestimate the magnitude of the HIV epidemic and do not represent the actual number of people infected with HIV (prevalence) or the number of people newly infected with HIV during one year (incidence). Surveillance data do not provide information on those HIV-infected persons who remain untested and undiagnosed. CIDPC has estimated that approximately

30% of the estimated 56,000 Canadians living with HIV infection at the end of 2002 were unaware of their infection.23 In addition, the completeness of surveillance data is affected by under-reporting, reporting delays, and incomplete information for some variables (especially ethnic status and exposure category). Reliance on the 'HIV-endemic' exposure category does not capture information on persons from countries where HIV is endemic who are assigned to an exposure category higher up in the hierarchy (such as MSM or IDU). Further limitations to the HIV/AIDS surveillance data are detailed in 'HIV and AIDS in Canada Surveillance Report to December 31, 2004'.²⁵

Interpretation

Despite the limitations associated with surveillance data, a picture emerges of the pattern of the HIV/AIDS epidemic among persons from countries where HIV is endemic. The observed trends suggest there is an increasing proportion of reported HIV and AIDS cases attributed to this group and that this group is overrepresented in the Canadian HIV epidemic. Furthermore, those particularly affected include persons under the age of 40 and women, including women of childbearing age. Most of the people associated with the HIV-endemic exposure category identify themselves as being of 'Black' ethnicity.

Public Health Implications

There is a need for improved HIV/AIDS surveillance data at the national level to permit better monitoring and characterization of trends in HIV among persons from HIV-endemic countries, which will in turn provide better data to guide prevention and care programs for this group. To accomplish this, CIDPC is strengthening its collaboration with provincial/territorial governments and community stakeholders specifically to find ways to improve the quality of exposure category and ethnicity information for the population born in countries where HIV is endemic. It is also important that further research in this area is developed to better understand the reasons behind these observed trends and to assess the best way to address them. More complete surveillance and research information would enable policy makers, public health officials, and community members to jointly develop, implement and sustain culturally relevant prevention, education and support services for this population across Canada.

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*** Correspondence with CIC, March 15 2005.