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HIV Prevention in Canada
The Future Is Long Acting: HIV Prevention Insights for Canada From CROI

Released: March 18, 2026

Alexander Wong
Alexander Wong, MD, FRCPC
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Key Takeaways
  • Resistance data from the PURPOSE 1 and PURPOSE 2 studies of lenacapavir and new data on MK-8527 dose selection further support expanding options for long-acting PrEP.
  • Low awareness but high willingness to use PrEP among people who use drugs in Canada indicates that education and low-barrier access points for PrEP are critical to improving uptake.

CROI 2026 continued its long-standing tradition of scientific excellence in HIV innovation and research amidst a complicated global health landscape. Along with the ongoing funding challenges for HIV research and care delivery, the past year saw increases in the amount and degree of misinformation propagated by social media in infectious disease prevention and treatment. This has directly led to decreased HIV prevention uptake and adherence to antiretroviral therapies, as well as mistrust in HIV vaccine development as a whole.

For those of us in Canada and globally who provide care for persons living with HIV, we have an ongoing obligation to fight misinformation both offline and online and to advocate for the ongoing funding and scientific integrity of HIV research and care delivery programs around the world.

HIV and Sexually Transmitted Infection Epidemiology in Canada
Here in Canada, although the overall incidence of new HIV infections across the country remained stable in 2024 at 6.3 diagnoses per 100,000 people, the rates of HIV acquisition in the Prairie provinces of Manitoba and Saskatchewan (where I practice) remain unacceptably high. Based on recently released data from the Public Health Agency of Canada, incidence rates of HIV in Manitoba (19.5 diagnoses per 100,000 people) and Saskatchewan (18.6 diagnoses per 100,000 people) are approximately 3 times greater than the national average.

Transmission dynamics are similar in these 2 provinces, with high rates of HIV infection because of heterosexual sex, which is further amplified by a concurrent syphilis epidemic that has proven difficult to control. Transmission because of the injection of substances also continues to be relevant in both provinces.

The sustained control of these outbreaks requires a comprehensive public health approach that combines 2 approaches:

  1. Harm reduction and widespread rollout of treatment and prevention strategies for all sexually transmitted and blood-borne infections
  2. Comprehensive clinical and nonclinical supports for persons with concurrent mental health diagnoses and substance use disorder, as well as those experiencing houselessness and poverty

New Strategies for HIV Prevention
Pragmatic and convenient approaches to HIV prevention are needed to help reduce the number of new HIV infections in high-incidence settings, like Manitoba and Saskatchewan, such as long-acting injectables. The ongoing PURPOSE 4 study, currently underway, will provide important information on the efficacy and safety of twice-yearly lenacapavir (LEN) for HIV prevention in different patient populations, including persons who use and inject drugs.

Follow-up data through the end of the double-blind phases for both the PURPOSE 1 and PURPOSE 2 studies were presented at the conference and continued to show very high rates of protection against HIV acquisition for over 4,300 persons receiving LEN, with only 5 new HIV infections recorded in this population.

Three of these 5 incident infections were found to have the N74D resistance mutation, indicating that capsid resistance can develop in the small number of persons who acquire HIV infection while receiving LEN. However, the rarity of incident infections and resistance still support LEN implementation for long-acting HIV prevention.

Although long-acting, injectable pre-exposure prophylaxis (PrEP) has revolutionized HIV prevention, there are still people who cannot tolerate injections or who prefer oral PrEP. Fortunately, there may soon be long-acting PrEP options for them as well: Further information on MK-8527 dose selection was presented at the meeting.

MK-8527 is an investigational nucleoside reverse transcriptase translocation inhibitor, which is being studied as a once-monthly oral option for HIV prevention in the EXPrESSIVE studies. An 11-mg oral dose is predicted to offer protection against HIV infection and allow for an additional 1-week “window” for people who might take their therapy late.

Unfortunately, despite these advances in PrEP, there are still major gaps in PrEP knowledge among the general public, which greatly hinders uptake. My Canadian colleagues, Drs Mark Hull and Darrell Tan, presented data from their work among people who use drugs in Vancouver’s Downtown Eastside. They documented low awareness yet high willingness to use PrEP, with a high preference for injectable options vs oral options, and no clear preference between injections every 2 months or every 6 months.

Taken together, these studies illustrate the growing body of evidence for long-acting PrEP agents and provide substantial hope that the expanding repertoire of PrEP options will increase acceptance and uptake. However, educating people who are using substances about PrEP and creating low-barrier access points for PrEP are critical to improving uptake of PrEP and retention in care both in Canada and globally.

Your Thoughts
What similarities can you draw between the challenges with PrEP uptake in this region and your own clinical practice? What are some practical strategies for improving PrEP education that you can implement today? Leave a comment to join the discussion!

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