PrEP-ing for HIV

by Rehnuma Islam

Graphic design by Amy Assabgui

Approximately 62 000 Canadians are living with the Human Immunodeficiency Virus (HIV).1 In fact, roughly two thousand Canadians are diagnosed with HIV every year, and around 13% are unaware of their HIV positive status.1 HIV diagnosis involves testing for antibodies against the virus and viral components (e.g., antigens or nucleic acid) in blood samples. More recently self-testing was approved for use within Canada.2 HIV is contracted following exposure to vaginal fluid, semen, blood or breast milk  and often manifests flu-like symptoms.2 As the disease progress into a chronic HIV infection, it can be asymptomatic.2 Left untreated, HIV enters a phase where the immune system is severely damaged, ultimately favouring  opportunistic infections.2 This phase of the disease is termed Acquired Immunodeficiency Syndrome (AIDS) and the viral load is high. Without treatment, the estimated survival within this phase is around three years.2 

There are numerous preventative measures one can take to avoid contracting HIV. Some of which include frequent status testing, discussing one’s status among partners, practicing safe sex, and not sharing needles. According to Dr. Darrell Tan, a clinician-scientist at St. Michael’s Hospital and associate professor at the University of Toronto; “We have this relatively underutilized but really […] blockbuster intervention which is Pre-Exposure Prophylaxis (PrEP). So, a lot of my research program involves working on PrEP, which is a hugely effective and safe intervention that we don’t utilize well enough in Canada, unfortunately.”

Dr. Darrell Tan
Clinician-scientist at St. Michael’s Hospital
Associate professor at the University of Toronto

Photo Credit: Dr. Darrell Tan

Dr. Tan was elected as a governing council member of the International AIDS Society and is a Canadian Research Chair in HIV prevention and STI Research. While completing his BSc at McGill University in Microbiology and Immunology and International Development Study, Dr. Tan was interested in the biological and societal impacts of HIV, particularly its devastating effects within the LGBTQ2+ community. Dr. Tan’s passion to continue studying HIV led him to complete his MD and residency training in infectious disease, and PhD in clinical epidemiology at the University of Toronto, where he continues his mentorship and research. 

PrEP is given to individuals that are HIV negative to reduce the risk of contracting HIV. Previous research has highlighted the efficacy and safety of PrEP. However, even after a decade, individuals at risk of contracting HIV are seldom prescribed PrEP due to a lack of education and conversation surrounding its use. Currently, Dr. Tan’s research investigates the implementation of PrEP as an intervention against HIV. Past projects with PrEP implementation have helped clinicians learn about and prescribe PrEP.3 Other projects have helped link different parts of the health care system to identify individuals that could benefit from PrEP services when visiting a clinic.4 There is currently a study aimed at identifying barriers and facilitators in an individual’s choice to use or not use PrEP.5 These vital questions surrounding the efficacy and usefulness of PrEP will improve sexual health and wellbeing within the gay and lesbian communities, while efforts are being made to reach racial minorities, genderqueer individuals, and various other subjugated groups.

Dr. Tan acknowledges that there remain many hurdles to improve the public discourse around PrEP use and emphasizes the problem stems from the top down; “It’s a failure of our public health and health system that everybody does not know about it because, obviously knowledge is power and is the first step to getting people access to something that is extremely effective and safe. Frontline clinicians do not always know about the product. I speak to clinicians all the time including primary care providers who could be potentially prescribing this to patients in the clinic, but sometimes just do not have the information, they just don’t know about it.” Dr. Tan acknowledges that even on a personal level, an individual’s use of PrEP is not common conversation among social circles, further perpetuating the concerning lack of knowledge about HIV preventative measures among the public. 

HIV treatment has come a long way from treatments with side effects to relatively safe treatments that rely on a pill a day and pose minimal long-term side effects. Dr. Tan discusses recent improvements in treatment, such as the long-acting injection (lasting two months) which boasts improved safety profiles and gives individuals more freedom to live their daily lives. Dr. Tan notes that there are not only treatments for symptoms, but also treatments can prevent the spread of HIV; “the treatment of folks who are living with HIV is associated with not only benefits for that person, but also reduction in the risk of them transmitting HIV to their partners. We can actually reduce that risk, right down to zero – that is an important difference, it’s not a really low risk it’s zero risk, which completely revolutionizes how people can think about their sex lives or partners – it helps undo stigma.” And while more improved treatments are being developed, Dr. Tan recognizes that “we need to do much more in terms of equitable distribution of all these tools”.

Outside of his research, Dr. Tan also acts as a Department of Medicine’s LGBTQ2+ ambassador and hopes that the program will improve engagement with and visibility of the LGBTQ2+ community across healthcare and educational institutions. Recent data suggests that half of HIV patients on drug treatments reported avoiding HIV services because of stigma and discrimination.1 Dr. Tan’s role as an ambassador involves breaking the code of silence against all forms of discrimination, specifically those against sexual minorities. 

Sexually transmitted infections are a reality many Canadians live with, however, individuals such as Dr. Darrell Tan are improving the narratives in our living room and in our physician’s office. The future is promising for pre- and post-treatment options of HIV, the next step is to begin removing the stigma surrounding HIV. 


  1. Government of Canada / Gouvernement du Canada [Internet]; 2021 [cited 2022Jan7]. Available from: 
  2. About HIV/AIDS [Internet]. Centers for Disease Control and Prevention. Centers for Disease Control and Prevention; 2021 [cited 2022Jan7]. Available from: 
  3. Sinno J, Doria N, Cochkanoff N, et al. Attitudes and practices of a sample of Nova Scotian physicians for the implementation of HIV pre-exposure prophylaxis. HIV/AIDS – Research and Palliative Care. 2021;Volume 13:157–70.  
  4. Sharma M, Chris A, Chan A, et al. Decentralizing the delivery of HIV pre-exposure prophylaxis (prep) through family physicians and Sexual Health Clinic Nurses: A dissemination and implementation study protocol. BMC Health Services Research. 2018;18(1).  
  5. Cox J, Apelian H, Moodie EEM, Messier-Peet M, et al. Use of HIV pre-exposure prophylaxis among urban Canadian gay, bisexual and other men who have sex with men: A cross-sectional analysis of the engage cohort study. CMAJ Open. 2021;9(2).