AIDS in Canada

AIDS IN CANADA

The Canadian Epidemic
(data from Health Canada “Epi-Updates”, May 2004.)

The first case of AIDS was reported in Canada in 1982.

Twenty five years later, the epidemic is estimated to have claimed more than 20,000 lives.

Almost 58,000 people living in Canada are currently infected with HIV, approximately 1/3 of who don’t know they’re infected.

Due to improved drug and therapy programs the rate of AIDS deaths has been constant for the last three years, at 1,500, however new infections continue to rise. The epidemic is growing: In 1996, there were an estimated 40,000 people living in Canada with HIV, in 2001 there were 49,000 and at the end of 2003 there were 56,000. In 2002 there were between 2,800 and 5,200 new infections, alone.

The HIV/AIDS epidemic exists differently in different populations within Canada:

  • Early in the epidemic it primarily affected men who have sex with men (MSM) and those who received blood and blood products.
  • The current epidemic (1997+) primarily affects MSM, injection drug users (IDU), and, increasingly, women and Aboriginal people.
  • Although the HIV/AIDS epidemic no longer affects MSM to the same extent it did in the early mid-80s, this group still accounts for the largest number of new infections and deaths due to AIDS. In Montreal, it is estimated that 15% of MSM are infected with HIV. A continued increase in risky behaviour since the mid-90s is particularly dangerous to this population: data from two recent studies in Vancouver and Montreal showed that 56% of HIV-positive men and 40% of HIV-negative men reported having engaged in receptive unprotected anal intercourse in the last year. Suggested reasons for this increase in risk behaviour include feelings of complacency or optimism related to the success of antiretroviral therapy and a lack of direct experience with the AIDS epidemic in the younger generation of gay men.
  • IDUs represent a significant proportion of Canadians with HIV. Surveillance studies show varying prevalence rates among IDU: In Victoria, HIV prevalence is 16%, Montreal 23%, Ottawa 20% and Quebec 16%. Women, youth and Aboriginal IDUs are particularly at risk of infection.


For the last 5 years, women accounted for 25% all new HIV infections. Among adolescents and young adults (15 – 30 years), women accounted for around 40% of infections in that age group. Many women who account for the increase in infections are Aboriginals, injection drug users or recent immigrants from countries where HIV is endemic (i.e. countries where HIV is predominantly spread via sexual contact).

Aboriginal peoples and Blacks are increasingly overrepresented in the population living with HIV in Canada. In 2001, Aboriginal peoples accounted for 3.3% and Blacks, 2.2% of Canada’s population. In the same year, they respectively accounted for 5.5% and 15.3% of AIDS cases and in 2002, these proportions were 12.9% and 18.3%. People from countries where HIV is endemic accounted for 6 – 12% of new infections in 2002.

Recent gains in ARV treatment, however, have virtually eliminated new perinatal infections. The proportion of infected babies born to HIV-infected mothers has decreased from 50% in 1996 to 2% in 2002.

High Income Countries and HAART 
High income countries contain only a small portion of the world’s population living with HIV, but they have some unique problems related to high treatment levels with anti-retroviral drugs (ARVs)[1].

Highly Active ARV Treatment (HAART) can be very effective at suppressing levels of virus and increasing CD4+ cell count to fight infection. Advances in HIV/AIDS treatment have led to more people delaying progression to AIDS and living longer and healthier lives[2]. However, with the HI virus’ adeptness at mutating or changing key sequences in its genome, resistant strains of virus that cannot be killed by ARVs have evolved. A recent study in the U.S. showed that 53% of patients being treated with HAART after 6 months failed treatment, with levels of circulating virus rising to detectable or even to pretreatment levels[3]. ARV-resistant strains of HIV are now being transmitted in the population. The overall prevalence of primary drug resistance to at least one ARV drug in Canadians infected with HIV is 7%. This figure is similar in other countries where HAART is widely used[4].

While ARVs have significantly reduced the number of AIDS-related deaths in high-income countries in recent years, the number of new infections has not decreased. New infection levels have remained constant at ~40,000/year in the U.S.[5] and ~4,000/year in Canada[6]. The epidemic is growing, in part, due to risky behaviour because widespread access to ARV treatment is fuelling a dangerous myth that AIDS has been defeated. In the U.S., one-quarter of the people living with HIV do not know they are infected[7] and in Canada, it is one-third[8]. Within Manhattan, almost 2% of the adult population is infected with HIV[9].

The number of people initiating HAART in high-income countries is increasing steadily and important lessons are being learned for application to the rest of the world where massive treatment initiatives are being launched in countries where the burden of the HIV/AIDS epidemic is felt the most.

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  1. UNAIDS Fact Sheet 2004, “AIDS epidemic in High-income countries”.
  2. Piliero, Peter J. “Treatment of HIV/AIDS in patients failing their first HAART regimen”. www.hivandhepatitis.com
  3. Poor adherence to the antiretroviral therapy regimen was significantly associated with treatment failure. Piliero, Peter J. “Treatment of HIV/AIDS in patients failing their first HAART regimen”. www.hivandhepatitis.com
  4. Health Canada “Epi-Updates”, May 2004.
  5. Centre for Disease Control, 2003. www.knowhivaids.org
  6. Centre for Infectious Disease Prevention and Control, end of 2002. “HIV and AIDS in Canada: Surveillance Report to December 31, 2003”.
  7. UNAIDS Fact Sheet 2004, “AIDS epidemic in High-income countries”.
  8. Centre for Infectious Disease Prevention and Control, end of 2002. “HIV and AIDS in Canada: Surveillance Report to December 31, 2003”.
  9. UNAIDS Fact Sheet 2004, “AIDS epidemic in High-income countries”.