At a Glance - HIV and AIDS in Canada: Surveillance Report to December 31^st, 2010

HIV/AIDS Surveillance

The following report outlines HIV and AIDS surveillance data and provides a description of persons who have been diagnosed with HIV and AIDS in Canada. Surveillance data understate the magnitude of the HIV epidemic and consequently do not represent the total number of people infected with HIV (prevalence) or the number of people newly infected each year (incidence). Some of the reasons for this include the fact that surveillance data are subject to delays in reporting, underreporting and changing patterns in HIV testing behaviours (who comes forward for testing). In addition, surveillance data can only tell us about persons who have been tested and diagnosed with HIV or AIDS and not those who remain untested and undiagnosed. Furthermore, because HIV is a chronic infection with a long latent period, many persons who are newly infected in a given year may not be diagnosed until later years.

The Public Health Agency of Canada (PHAC) produced estimates of HIV incidence and prevalence to the end of 2008^{Footnote 1}. These estimates were created using a combination of methods, incorporating data from a wide variety of sources, including HIV test reports, AIDS case reports, population-based surveys, targeted epidemiologic studies and census data. It was estimated that at the end of 2008, there were approximately 65,000 (54,000 to 76,000) people living with HIV (including AIDS) in Canada, of whom 26% were unaware of their infection. The number of people newly infected with HIV in Canada in 2008 was estimated to be between 2,300 and 4,300.

HIV Surveillance

Since reporting began in 1985, a cumulative total of 72,226 positive HIV test reports were reported to PHAC through December 31st, 2010. In 2010, 2,358 HIV cases were reported; a 2.4% decrease since 2009 (2,416). Figure 1 illustrates the trend in annual HIV case reports since 1996, demonstrating a steady decrease in the number of reported cases until the year 2000, followed by an increase through 2002, where it has remained fairly stable over the last nine years.

Figure 1. Number of positive HIV test reports, by year of diagnosis, 1996-2010

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Ontario accounted for the highest proportion of cases in 2010, comprising 45.5% of all positive HIV tests reported to PHAC. This was followed by Québec (20.4%), British Columbia (12.8%), Alberta (8.1%) and Saskatchewan (6.9%). Table 6B provides the number and proportion of case reports by province and territory.

The national rate for positive HIV test reports among adults in Canada for 2010 was 8.2 (per 100,000 population). Provincial and territorial rates reveal significant variation across the country. Figure 2 shows the increase seen in Saskatchewan since 2002, reaching a high of 23.8 per 100,000 population in 2009. In 2010, the rate of positive HIV tests in Saskatchewan (19.1 per 100,000) was more than double the national average of 8.2 per 100,000. The next highest rates in 2010 were reported in Manitoba (12.3 per 100,000) and in Ontario (9.7 per 100,000). Despite increasing rates observed in Saskatchewan in recent years, the number and rate of newly diagnosed cases decreased in 2010 compared to 2009.

Figure 2. Rate (per 100,000 population) of positive HIV test reports among adults (≥15 years)
by province/territory and year of diagnosis

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Historically, females have comprised a steadily increasing proportion of HIV cases reported since 1985. However, the proportion of HIV cases among adult females (≥15 years), has remained generally stable over the last 10 years, with a peak of 27.7% in 2006, with only slight fluctuations since 2001. In 2010, 23.0% of all HIV reports were among adult females.

Since 1985, the 30-39 age group has comprised the largest proportion of HIV case reports, although the proportion has been steadily decreasing in the past decade. Since 2005, the proportion of HIV case reports attributed to the older age groups (40-49 and 50+) has generally increased. In 2010, the largest proportion of cases was attributed to those aged 30-39 (29.9%), followed by the 40-49 age group (27.1%), the 20-29 age group (21.4%), the 50+ age group (19.0%), the 15-19 age group (2.0%), and the 0-14 age group (0.6%).

Age distribution among females varied significantly from males, with females being diagnosed at a younger age than males. In 2010, females had a higher proportion of case reports attributed to the four younger age groups: 0-14 (1.1% of female cases vs. 0.5% of male cases), 15-19 (3.4% vs. 1.6%), 20-29 (23.4% vs. 20.9%) and 30-39 (35.0% vs. 28.4%). In contrast, males had a higher proportion of case reports attributed to the two older age groups, i.e. 40-49 (29.3% of male cases vs. 20.4% of female cases), and those over the age of 50 (19.2% vs. 16.6%). See Figure 3.

Figure 3. Age distribution of positive HIV test reports in Canada, by sex, 2010

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Exposure category was reported for 51.1% of HIV case reports among adults in 2010. The following percentages include only those records with information about risk associated with transmission of HIV. Exposure category data are not available from Québec, and therefore are not included in the following discussion of exposure category trends.

When HIV reporting began in 1985, men who have sex with men (MSM) accounted for over 80% of all cases. Although MSM is still the predominant exposure category, the proportion has decreased significantly over the years. In 2010, 47.6% of all positive adult HIV cases with known exposure category were attributed to MSM.

Heterosexual contact, at 30.8% of case reports among adults in 2010, was the second most reported exposure category (13.2% attributed to having sexual contact with someone with no identified risk, 11.0% attributed to having sexual contact with a person at risk, and 6.6% to those of origin from an endemic country).

In 2010, injection drug use (IDU) was the third most frequently reported exposure category, accounting for 16.8% of HIV reports among adults that year. Overall, women had a higher proportion of HIV attributed to IDU than men (30.1% vs. 13.5%). See Figures 4A and 4B for complete exposure category breakdowns by sex.

Figure 4A. Proportion of positive HIV test reports among adult males (≥15 years),
by exposure category, 2010

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Figure 4B. Proportion of positive HIV test reports among adult females (≥15 years),
by exposure category, 2010

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Some variation is also observed when looking at exposure category breakdowns across the provinces. More specifically, in Ontario, British Columbia, Alberta, and the Atlantic provinces, MSM was the most frequently reported exposure category in 2010, while Saskatchewan’s primary exposure category was IDU and Manitoba’s was heterosexual contact with a person at risk.

HIV race/ethnicity reporting began in 1998, however Ontario and Québec do not submit race/ethnicity data with HIV test reports. Therefore, the following should be considered in the context of this data limitation and should not be considered nationally representative. In 2010, 68.9% of all positive HIV tests reported to PHAC were missing race/ethnicity information. Among HIV case reports with reported race/ethnicity in 2010, the breakdown is as follows: 47.5% White, 30.3% Aboriginal, 10.8% Black, 6.4% Asian, 2.3% Latin American, 1.8% South Asian/West Asian/Arab, and 1.0% Other.

Ontario HIV surveillance data^{Footnote 2}

Exposure category data are provided to PHAC by the HIV Laboratory, Public Health Ontario using provincially assigned exposure categories. Overall, a cumulative 30,800 HIV-infected persons have been newly diagnosed in Ontario as of 2009. Analysis on positive HIV test reports from 1985 to 2009 indicate that the proportion of cases with missing data for exposure category is relatively high, at 51%, and has not changed substantially in recent years^{Footnote 3}.

Unadjusted data submitted to PHAC and presented in this surveillance report show that from 1985 to 2009, the most frequently reported exposure categories were: MSM (66.7%), low-risk heterosexual transmission (10.9%), IDU (8.2%), persons from HIV-endemic regions (3.8%), and high-risk heterosexual transmission (3.4%)^{Footnote 4}.

Since October 1999, the Laboratory Enhancement Program (LEP) has collected additional information on risk factors and HIV testing histories from persons in Ontario undergoing HIV testing at the HIV Laboratory, Public Health Ontario. For this purpose, questionnaires are sent to all HIV positive cases as well as a random sample of HIV negative cases. The LEP also performs assays to distinguish recent infection on specimens from all newly diagnosed cases.  These data are not included in PHAC’s national surveillance data.

Adjusted data are presented in the provincial surveillance report to compensate for the large proportion of cases with unknown exposure category. This is done by assigning HIV-positive results of those with missing data to an exposure category using results from the LEP. Adjusted data show that the most prevalent exposure categories in Ontario from 1985 to 2009 were: MSM (59.9%), persons from HIV-endemic regions (13.0%), IDU (7.8%), low-risk heterosexual transmission (7.8%), followed by MSM/IDU (3.9%) and high-risk heterosexual transmission (3.4%)^{Footnote 5}.

Québec HIV surveillance data

HIV exposure category and ethnocultural origin data are collected by the Programme de surveillance de l’infection par le virus de l’immunodéficience humaine (VIH) using provincially-assigned exposure and ethnocultural origin categories.

The HIV laboratory of the Laboratoire de santé publique du Québec (LSPQ), of l'Institut national de santé publique du Québec (INSPQ), is PHAC’s sole data provider for Québec provincial HIV data.  It submits core elements such as sex, age and date of specimen collection, but does not capture any information related to exposure category or ethnocultural origin; these data are not submitted to PHAC and are therefore not presented in this report.

The 2010 mid-year Québec provincial surveillance report presents additional analyses however and shows that, between April 2002 and June 2010, there was a total of 3,138 newly diagnosed cases according to previous test history, of which 56.4% were attributed to MSM, 15.1% to heterosexual contact, 14.6% to persons from HIV-endemic countries, and 9.4% to IDU^{Footnote 6}.

With regards to race/ethnicity data, the most prevalent categories reported in Québec between April 2002 and June 2010 were as follows: Canadian (70.5%), Sub-Saharan Africa (9.4%) and Caribbean (8.9%, primarily Haitian)^{Footnote 7}.

AIDS Surveillance

It is important to note the limitations associated with reported AIDS diagnoses. AIDS surveillance data have not been available from the province of Québec since June 30, 2003, so the counts presented in this report are not an accurate reflection of the actual number of AIDS diagnoses in Canada. Furthermore, the province of Ontario undertook an IT-application change for AIDS case management and reporting in 2005. As a result of the conversion, reported AIDS diagnoses from Ontario for 2005 onwards do not contain any exposure category or race/ethnicity data. Caution must be used when interpreting AIDS trends over time nationally. Further details regarding these data limitations are available in Section III.

Since AIDS reporting began in 1979, there has been a cumulative total of 22,120 AIDS cases reported to PHAC through December 31st, 2010. In 2010, 188 AIDS cases were reported to PHAC; a 24.8% decrease since 2009. See Figure 5.

Figure 5. Number of reported AIDS cases, by year of diagnosis, 1979-2010

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In 2010, the majority of AIDS cases were reported in Ontario (49.5%), followed by British Columbia (21.3%), Alberta (16.0%) and Saskatchewan (8.0%).

In 2010, 82.4% of all reported AIDS cases were among males and 17.6% were among females (where sex was reported).

The majority of reported AIDS cases in 2010 were between the ages of 40 and 49 (37.8%), followed by those aged 50 years and over (28.7%) and those aged 30 to 39 years (24.5%).

Similar to the trend observed with HIV, age distribution of AIDS cases among females varied significantly from males. In 2010, females had a higher proportion of AIDS case reports in the younger age groups; those aged 0 to 14 years (6.1% of female cases vs. 0.0% of male cases), 15-19 years (3.0% female vs. 0.0% male), 20-29 years (12.1% vs. 6.5%) and 30-39 years (30.3% vs. 23.2%).

In contrast, males had a higher proportion of AIDS case reports in the older age groups: 40 to 49 years (41.3% of male cases vs. 21.2% of female cases) and 50 years and over age group (29.0% vs. 27.3%). See Figure 6.

Figure 6. Proportion of reported AIDS cases in Canada, by sex, and age group, 2010

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When looking at exposure category, the largest proportion of AIDS cases among adult males was attributed to MSM in 2010, with 34.7% of cases. This was followed by IDU (30.7%) and heterosexual contact (26.7%). In 2010, among adult female AIDS cases, the majority were attributed to IDU (56.3%), followed by heterosexual contact at 37.5%. See Figure 7.

Figure 7. Proportion of reported AIDS cases among adults (≥15 years) in Canada,
by sex and exposure category, 2010

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Race/ethnicity data were not provided for all AIDS cases reported to PHAC in 2010. Therefore, the following should be considered in the context of this data limitation and should not be considered nationally representative. In 2010, 44.7% of all reported AIDS cases had race/ethnicity information.

In 2010, 48.8% of all adult AIDS cases were identified as White, followed by 33.3% Aboriginal, and 8.3% Asian. See Figure 8. Trends in race/ethnicity since 2005 show that the proportion of AIDS cases among Aboriginal peoples was higher in 2009 and 2010 compared to 2008 and 2007, while there has been a corresponding decrease in the proportion of cases attributed to the White racial/ethnic category.

Figure 8. Proportion of reported AIDS cases in Canada, by race/ethnicity, 2005-2010

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Immigration

Changes to policies at Citizenship and Immigration Canada (CIC) can likely explain some of the increase in the number of positive HIV tests reported after 2001. On January 15, 2002, CIC added routine HIV screening for all applicants who require an Immigration Medical Examination (IME) and are 15 years of age or older, as well as for those children who have received blood or blood products, have or had a known HIV positive mother or are potential adoptees. In 2004, CIC discontinued the routine HIV testing of potential adoptees.

In June 2002, the Immigration and Refugee Protection Act (IRPA)^{Footnote 8} was implemented, requiring that applicants be assessed for the health grounds of inadmissibility (danger to public health, danger to public safety and excessive demands on health or social services). However, the Act exempted certain groups of immigrants from excessive demand evaluation. Information on this legislation is available on the CIC website.

Between January 15, 2002 and December 31, 2010, there were 4,768 applicants who underwent an IME who tested positive for HIV^{Footnote 9}. In 2010 alone, 488 applicants undergoing an IME tested HIV-positive. Of these, 231 were identified by HIV testing in Canada, and 257 were identified outside of Canada.

IME HIV testing undertaken in Canada is managed and reported in the same manner as all other positive HIV tests diagnosed among Canadians, and is included in provincial/territorial HIV reporting to PHAC. In September 2004, CIC introduced reporting to provincial/territorial health authorities of HIV cases, medically examined overseas, who have entered Canada.

Of the 488 HIV-positive diagnoses in 2010, 271 (55.5%) were born in Africa and the Middle East, 147 (30.1%) in the Americas, 50 (10.2%) in Asia and 20 (4.1%) in Europe. In 2010, the 231 HIV-positive tests identified in Canada represented 9.8% (231/2,358) of the positive HIV tests reported to PHAC.

Canadian Perinatal HIV Surveillance Program

The Canadian Perinatal HIV Surveillance Program is an active surveillance system comprising all identified infants and children born to mothers infected with HIV. The program includes infants identified as exposed to HIV during pregnancy and older infants and children not identified in the perinatal period or born outside Canada who are receiving care for HIV infection. Between 1984 and 2010, there have been 3,317 infants identified as being perinatally exposed to HIV. The number of HIV-exposed infants reported per birth year increased between 2004 and 2008 (from 182 to 240). In 2010, 235 cases of perinatally HIV-exposed infants were reported to PHAC.

Between 1984 and 2010, the overall proportion of HIV-exposed infants whose mothers' HIV status was attributed to the exposure category of heterosexual contact was 72.9%, while 24.5% were attributed to injection drug use.

Although the number of infants exposed to HIV has increased over time, the proportion of infants born in Canada confirmed to be HIV-infected has decreased gradually from >20% prior to the advent of antiretrovirals during pregnancy (AZT monotherapy after 1994, HAART after 1996) to 1.7% in 2010. Correspondingly, the proportion of HIV-positive mothers receiving antiretroviral therapy has increased, attaining 93.2% in 2010 (Section II). 

Black women have the highest proportion of perinatally HIV-exposed infants amongst all other ethnic groups in Canada, and represent 49.8% of all reported cases in 2010. This is followed by 20.4% of cases attributed to Aboriginal women and 20.0% attributed to White women.

Interpretation

The annual number of HIV cases reported to PHAC for the year 2010 is the lowest reported since 2002, although overall, the annual number of cases has remained fairly stable over the past decade. Increases during this time, however, were observed among specific population groups including younger females, older males and Aboriginal peoples.

Saskatchewan had the highest rate of positive HIV test reports in 2010 compared to the rest of Canada, and has exceeded the national average over the past six years. While nationally, the number of HIV cases attributed to injection drug use has declined in recent years, the province of Saskatchewan has experienced a significant increase in the number of IDU-attributed HIV cases. Similar to 2009, cases observed in 2010 are primarily in the Aboriginal race/ethnicity category, which has also contributed to the observed increase in the proportion of cases among Aboriginal peoples at the national level. In response to this situation, the Saskatchewan Ministry of Health launched a provincial HIV strategy, which includes further investigation of this increase in case reports.

Overall, when looking at the different risk exposures for HIV, MSM is still the leading reported risk exposure in Canada; this is followed by heterosexual contact and injection drug use. However, the pattern of risk exposure differs by province/territory as well as by race/ethnicity.

Distinct differences between the sexes are observed in terms of age at diagnoses of HIV and AIDS, whereby females are being diagnosed at a younger age compared to males. The proportion of HIV cases among older Canadians has been gradually increasing since reporting began in 1985, with a higher proportion of males occurring in the older age groups.

Given the variations in the HIV and AIDS case reports across different demographics (e.g., race/ethnicity, age and sex), the data presented in this Surveillance Report highlight the need for population-specific interventions.

To obtain a copy of the report, send your request to:

Centre for Communicable Diseases and Infection Control
Public Health Agency of Canada
Room 1341, 100 Eglantine Driveway, Health Canada Building
A.L. 0601A, Tunney's Pasture
Ottawa, ON  K1A 0K9
E-Mail: ccdic-clmti@phac-aspc.gc.ca

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Footnote 1

Public Health Agency of Canada. Summary: Estimates of HIV prevalence and incidence in Canada, 2008. Ottawa: PHAC, 2009:1-3.

Footnote 2

Most recent data for the province of Ontario available to 2009.

Footnote 3

Ministry of Health and Long-Term Care. HIV/AIDS in Ontario: Preliminary Report, 2009 (PDF document). Tables 1.2, 1.3.

Footnote 4

Ibid.

Footnote 5

Ibid.

Footnote 6

Gouvernement du Québec. Surveillance des infections transmissibles sexuellement et par le sang (PDF document). Mise à jour des données au 30 juin 2010. Table 5.

Footnote 7

Ibid.

Footnote 8

Citizenship and Immigration Canada. Immigration and Refugee Protection Act.

Footnote 9

Health Branch (HB), formerly Health Management Branch (HMB), Citizenship and Immigration Canada - Database on HIV, as of February 2011.