- There are at least 122,000 people in Canada who could benefit from HIV prevention medication
- It is estimated that only 19% of these people are accessing HIV pre-exposure prophylaxis (PrEP)
- To decrease new HIV infections in Canada, barriers to accessing PrEP need to be removed
The use of HIV medicines to help prevent contracting HIV is called pre-exposure prophylaxis (PrEP).
Currently approved options for PrEP include the following:
- TDF + FTC (sold as a pill called Truvada and available in generic formulations)
- TAF + FTC (sold as a pill called Descovy)
- cabotegravir (ultimately taken as an injection every two months)
In addition, later this year a long-acting injectable formulation of the drug lenacapavir for use as PrEP will be approved in Canada. What’s more, several years from now there may be long-acting pills to provide protection from HIV that can be taken as infrequently as once a month.
Yet HIV infections continue to occur in Canada.
A team of researchers with the Public Health Agency of Canada (PHAC), the Community-based Research Centre in Vancouver, the University of Victoria and McGill University cooperated in a study to estimate the size of some populations who would benefit from PrEP. Where possible, their analysis also explored populations of people who could benefit from PrEP but who were not using it.
The researchers used health-related information gathered from research surveys in Canada by other organizations that focused on two key subpopulations disproportionately affected by HIV:
- gay, bisexual and other men who have sex with men (gbMSM)
- people who inject drugs (PWID)
Using Canadian PrEP guidelines, the research team estimated the proportion of people who would be suitable candidates for PrEP (and the surveys sometimes yielded information on whether people were using PrEP).
Results
Taking all the information that the research team accessed, here are some key findings:
- An estimated 99,300 gbMSM could benefit from PrEP.
- An estimated 22,400 PWID could benefit from PrEP.
In total, this would approach 122,000 people.
Despite these figures, data suggest that only 23,644 people (about 19%) were using PrEP in 2021 (the last time the research team accessed the survey data).
The researchers estimated that at the time the surveys were conducted about 67% of gbMSM who could have been using PrEP were not taking it and none of the PWID who could have benefited from PrEP were taking it.
Barriers to PrEP
According to the researchers, other studies have identified “numerous barriers” that can prevent eligible people from using PrEP, including the following:
- HIV-related stigma
- self-perception of low HIV risk
- misunderstanding who should use PrEP
- barriers within health systems
- challenges with adherence to PrEP pills
- concerns about potential side effects
The researchers stated that “addressing these barriers may increase PrEP uptake among individuals with indications for use [of PrEP] in Canada.”
Treatment as prevention
The research team underscores work by scientists in British Columbia who have been promoting a combination of strategies, such as Treatment as Prevention (TasP) and PrEP, for different populations. TasP works because the vast majority of people who take HIV treatment (antiretroviral therapy; ART) as directed can suppress the level of HIV in their blood so low that it becomes undetectable with routinely used lab tests. Well-designed clinical trials have found that ART users with a suppressed viral load cannot pass on the virus to their sexual partners.
However, research suggests that about 11% of people with HIV in Canada are not aware of their infection. Thus, more HIV testing needs to happen so that people who test positive can be offered treatment and people who test negative who are at risk for HIV can be offered PrEP.
The research team encourages health systems to expand the availability of PrEP though “tailored approaches in Canada” to help reduce new HIV infections. They stated that deploying teams of nurses to help monitor and dispense PrEP could be useful. Also, they encourage primary care doctors to make use of educational initiatives around PrEP so they can help address the unmet needs uncovered by the present study.
The researchers stated that initiatives around harmful use of alcohol and drugs need to be integrated into PrEP care programs, so that people with these issues can be helped.
Finally, the researchers noted that long-acting injectable PrEP “provides another potential means to expand coverage and possibly address adherence for some key populations.”
Moving toward success
Reducing the number of new HIV infections in Canada will involve more than just injections or pills. As such, the researchers made the following statement:
“Effective PrEP policies, including inclusive eligibility criteria, sustainable funding mechanisms, and accessible delivery models, are crucial to ensuring that PrEP benefits those who need it. PrEP should be integrated with other HIV prevention strategies, such as testing and treatment, in order to maximize its public health impact. Well-designed and inclusive PrEP policies can increase PrEP uptake and adherence, ultimately helping to reduce HIV transmission across Canada.”
PWID and gbMSM are two key populations that are at risk for HIV. Future studies should explore PrEP deployment in other populations affected by HIV.
—Sean R. Hosein
Resources
Prescribing PrEP and PEP: Canadian Guideline – CATIE and CIHR Pan-Canadian Network for HIV and STBBI Clinical Trials Research (CTN+)
Updated Canadian HIV prevention guidelines released – CATIE News
Canadian guideline on HIV pre- and postexposure prophylaxis: 2025 update
REFERENCES:
- Yang Q, Wu HX, Lachowsky N, et al. Estimating the percentage and number of people with indications for HIV pre-exposure prophylaxis (PrEP) within two key populations, Canada, 2021. Canadian Journal of Public Health. 2026; in press.
- Jacobsen K, Babin C, Gormezano A, et al. Willingness to disclose sexual orientation and gender identity on federal government surveys: A community-based research study with gay, bisexual, transgender, and queer men and nonbinary and Two-Spirit people in Canada. Canadian Journal of Public Health. 2026; in press.
- Williams A, Sorge J, Périnet S, et al. Estimating the population size of people who inject drugs in Canada, 2021. Canada Communicable Disease Report. 2025 Oct 9;25(9):364-373.
- Oo MM, Karabelas-Pittman S, Hull M, et al. Impact of “absolute” versus “relative” HIV risk communication on pre-exposure prophylaxis interest in Canada: a randomized survey. AIDS Care. 2025 Nov 19:1-12.
- Yeong SK, Ye M, Barrios R, et al. Unsuppressed HIV viral load among people living with HIV by exposure category in British Columbia, Canada from 2005 to 2020: a population-based cohort study. BMC Global and Public Health. 2025 Oct 9;3(1):90.