ONPrEP Cohort: A community-based cohort study of HIV pre-exposure prophylaxis in Ontario

In Progress

Access to Medications

HIV/Sexually Transmitted and Blood-borne Infections

As a relatively new and highly effective option for HIV prevention, pre-exposure prophylaxis (PrEP) could greatly reduce new HIV infections in Ontario.

While PrEP has been available on a limited scale for several years, formal approval of the drugs tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for use as PrEP by Health Canada in February 2016 has helped to increase community interest in PrEP and led more people to use it.

How will pre-exposure prophylaxis (PrEP) be used by communities most impacted by the HIV epidemic?

What potential benefits and challenges will arise as PrEP use grows?

To find out, we are enrolling 800 HIV-uninfected people across the province who are using PrEP, to learn more about how people use this medication in their daily lives.

We hope to answer important questions about the effectiveness of PrEP in real-world settings, and how it may impact things like overall sexual health, sexual behaviour, perceptions of HIV risk, and engagement in medical care.

Our pathways to impact

Our results will inform policy, practice, programming and further research in multiple ways, with the ultimate goal of making PrEP easier to access for those who need it.

  • Our results will be invaluable to front-line, community-based organizations and clinicians counseling clients about HIV prevention options, as providing data on real-world outcomes is the best way to help people make evidence-informed decisions.
  • Our findings on the predictors of these outcomes will help providers develop and deliver more effective, appropriate and targeted services to better support people who use PrEP.
  • Our data on the availability and accommodation of PrEP services will be incorporated to our ongoing efforts to engage more providers into PrEP delivery, and our data on engagement in care will help providers counsel clients and reorganize services to maximize retention.
  • To promote the affordability of PrEP medications, we will generate cost-effectiveness data on previously unexamined aspects of PrEP rollout in industrialized settings. This information will be used in ongoing advocacy for broader funding of PrEP. This work will build on ongoing efforts by our collaborating agencies to push for access to PrEP medication for all who could benefit from it.
  • Our cohort findings (especially biological and behavioural outcome data) will serve as data inputs for an ongoing dynamic mathematical model of HIV transmission in Ontario.
  • To promote the appropriateness of PrEP care, we will incorporate our findings into our existing training initiatives on PrEP, especially our implementation science initiative targeting education family physicians, nurses and other clinicians.

About the study

This is an open-cohort study of 800 HIV-uninfected people across the province who are using PrEP. Participants will be followed every six months for an initial planned follow-up period of two years. If participants transition off PrEP, we will still follow up with them, to investigate possible health disparities between those who remain in PrEP care and those who do not.

All study visits will be coordinated with participants’ regular PrEP care. At each visit participants will complete a questionnaire including items about their mental, physical and sexual health, their experience accessing health care, and their experience with PrEP. Participants may choose to complete these web-based questionnaires either at the study site or before or after their visit via an emailed, participant-specific link provided by study staff.

We will also be asking to collect medical information related to participants’ PrEP care. Site staff will be asked to complete case report forms at each study visit with details about the care they provide including HIV testing, testing and vaccinations for STIs, sexual health and adherence counseling, and other health monitoring completed as part of PrEP care. We will request permission from participants to collect their laboratory results for HIV and other STI tests directly from Public Health Ontario through data linkage once annually during participation in the study.

As this study is non-interventional and designed to track real-world implementation of PrEP, there are no specific requirements in our study protocol for how PrEP is being provided. There are, however, widely available and commonly used professional guidelines for PrEP provision that take into account the need for patient safety including screening for HIV and STIs and monitoring potential side effects of TDF/FTC. These guidelines also make recommendations for ongoing adherence and sexual health counseling and referrals to psycho-social supports as needed to promote patient health and optimize PrEP care.

Access to Medications

HIV/Sexually Transmitted and Blood-borne Infections

Dr. Darrell Tan

An infectious diseases physician and Canada Research Chair in HIV Prevention and STI Research, Dr. Darrell Tan is dedicated to improving the prevention, detection and management of HIV and sexually transmitted co-infections such as herpes and syphilis.


  • Ryan Lisk (ACT) Principal Investigator
  • Dr. V. Allen (Public Health Ontario)
  • Camille Arkell (CATIE)
  • Molly Bannerman (Women & HIV/AIDS Initiative)
  • Dr. Isaac Bogoch (Toronto General Hospital)
  • Mia Bondi (Regional HIV/AIDS Connection)
  • Deanna Clatworthy (HIV/AIDS Resources and Community Health)
  • Dr. David Knox (Maple Leaf Medical Clinic)
  • Dr. Alan Li (Ontario HIV Treatment Network)
  • Dr. John MacLeod (790 Bay Street Medical Clinic)
  • Dr. Paul Macpherson (Ottawa Hospital)
  • R. Ortiz Nunez (MAX Ottawa)
  • Dr. Janet Raboud (University of Toronto)
  • Jeff Reinhart (Sherbourne Health Centre)
  • Dr. Ayden Scheim (St. Michael’s Hospital)
  • Dr. Malika Sharma (Casey House)
  • Wangari Tharao (Women’s Health in Women’s Hands CHC)
  • James Wilton (Ontario HIV Treatment Network)
  • Dr. Kevin Woodward (Hamilton Health Sciences)


  • Canadian Institutes of Health Research
  • Ontario HIV Treatment Network
  • Canadian Foundation for AIDS Research
  • CIHR Centre for REACH in HIV/AIDS (REACH 2.0)


  • Asian Community AIDS Services
  • African & Caribbean Council on HIV/AIDS in Ontario
  • AIDS Committee of Ottawa
  • AIDS Committee of Toronto
  • Action Canada for Sexual Health and Rights
  • AIDS Committee of Windsor
  • The AIDS Network
  • Alliance for South Asian AIDS Prevention
  • Black Coalition for AIDS Prevention
  • Committee for Accessible AIDS Treatment
  • Canadian AIDS Treatment Information Exchange (CATIE)
  • Centre for Spanish-Speaking People
  • Gay Men’s Sexual Health Alliance
  • MAX Ottawa
  • Regional HIV/AIDS Connection
  • Sherbourne Health Centre
  • Trans Priorities Project, the 519
  • Women’s HIV/AIDS Initiative
  • Women’s Health in Women’s Hands CHC

Contact Info

Piragas Puveendran

Study Coordinator

(416) 864-6060 ext. 77395