HIV in Canada: A primer for service providers
The HIV treatment cascade
- The treatment cascade reflects the different services someone living with HIV needs to achieve optimal health outcomes.
- The treatment cascade is based on the successive steps that are needed for a person living with HIV to achieve an undetectable viral load.
The treatment cascade reflects the different services someone living with HIV needs to achieve optimal health outcomes, including HIV testing and diagnosis, linkage to appropriate medical care (and other health services), support while in care, access to HIV treatment if and when the individual is ready, and support on treatment. While enhanced engagement in the cascade may have a secondary benefit of reducing HIV transmission, the HIV treatment cascade does not include services for people who are HIV negative; these services are an additional component of an integrated framework.
The HIV treatment cascade has emerged as a convenient tool for assessing integrated health service delivery for people living with HIV. It is based on the successive steps that are needed for a person living with HIV to achieve an undetectable viral load. Research shows that people living with HIV who have an undetectable viral load are more likely to live long, healthy lives and are less likely to pass HIV to others. Starting from the total number of people living with HIV in a specific region (both diagnosed and undiagnosed), the successive indicators in the stages of engagement in the HIV treatment cascade are:
- total number of people living with HIV
- number of people diagnosed with HIV
- number of people linked to HIV care
- number of people retained in care
- number of people on HIV treatment
- number of people with undetectable viral load
At each stage of the cascade people may be lost to engagement and care as a result of many types of barriers, such as poor access to services; stigma and discrimination; poverty, food security and homelessness; and mental health and addictions issues. Typically only a small proportion of people living with HIV are engaged in all the steps needed to achieve an undetectable viral load.
In a strategic discussion paper released in 2014, UNAIDS used the HIV treatment cascade to propose that by 2020:
- 90% of all people living with HIV will know their status;
- 90% of all people with diagnosed HIV infection will receive sustained ART;
- 90% of all people receiving ART will have viral suppression (undetectable viral load).
The strategy is informally known as “90-90-90”, and if these targets are achieved, 81% of all people living with HIV will be on treatment and 73% will have an undetectable viral load – the key indicator of ongoing successful treatment—and, therefore, be significantly less likely to transmit the virus to others.” Modelling studies show that achieving these targets would result in the end of the epidemic spread of HIV by 2030.
In 2015, Canada endorsed the 90-90-90 targets. New 2014 estimates of the HIV treatment cascade in Canada were released in 2016. It is estimated that in 2014, 80% of people living with HIV were diagnosed, 76% of people diagnosed were on treatment, and 89% of people on treatment had an undetectable viral load. This means that, overall, an estimated 54% of people living with HIV in Canade had an undetectable viral load in 2014.
The HIV treatment cascade – patching the leaks to improve HIV prevention – Prevention in Focus
Changing the narrative: Why HIV prevention in Canada needs to embrace HIV treatment –Prevention in Focus
The Engagement Cascade – The Positive Side
Summary: Measuring Canada's Progress on the 90-90-90 HIV Targets – Public Health Agency of Canada
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- UNAIDS. 90-90-90: An ambitious treatment target to help end the AIDS epidemic. 2014. Available from: http://www.unaids.org/sites/default/files/media_asset/90-90-90_en_0.pdf
- Nosyk B, Montaner JSG, Colley G et al. The cascade of HIV care in British Columbia, Canada, 1996-2011: a population-based retrospective cohort study. Lancet Infectious Diseases. 2014 Jan;14(1):40–9.
- Gilbert M, Gardner S, Murray J, et al. Quantifying the HIV care cascade in Ontario: Challenges and future directions. Poster presented at: 24th Annual Canadian Conference on HIV/AIDS Research, 30 May 2015; Toronto. Available from: http://www.cahr-acrv.ca/wp-content/uploads/2012/10/InfDis_26_SB_MarApr2015_Final.pdf
- Summary: Measuring Canada’s progress on the 90-90-90 HIV targets. Government of Canada. 1 December 2016. Available at: http://www.healthycanadians.gc.ca/publications/diseases-conditions-maladies-affections/hiv-90-90-90-vih/index-eng.php