Darrell Tan




Dr. Darrell Tan is an infectious diseases physician, clinician-scientist and Canadian Institutes of Health Research (CIHR) New Investigator whose research focuses on clinical trials in human immunodeficiency virus (HIV) prevention and HIV/sexual transmitted infection (STI) co-infection. As Director of the University of Toronto Clinical Research Unit on HIV Prevention and co-leader of the CIHR Canadian HIV Trials Network Biomedical Prevention Working Group, he is leading multiple efforts to optimize the implementation of HIV pre- and post-exposure prophylaxis (PrEP and PEP) in Canada. These include Canada’s first demonstration project of daily oral TDF/FTC-based PrEP in Toronto MSM, the development of national Clinical Practice Guidelines on PEP & PrEP use, exploration of the relationship between syndemic health problems and clinical outcomes of PEP & PrEP, studies of nurse-led PEP & PrEP, and evaluations of novel antiretroviral PEP regimens.

Additional research interests are in the interaction between HIV and common co-infections such as herpes simplex virus type 2 (HSV-2) and syphilis, and the role of systemic inflammation in driving clinical outcomes in people living with HIV. He is also Co-Principle Investigator on two CIHR-supported multicentre randomized control trials including the a trial of anti-herpes medication for attenuating HIV disease progression, and a trial of enhanced syphilis screening in HIV-positive men.

Recent Publications

  1. McClymont, E, Tan, DH, Bondy, S, Albert, A, Coutlée, F, Lee, M et al.. HSV-2 infection and HPV incidence, persistence, and precancerous lesions in a cohort of HPV-vaccinated women living with HIV. Int J STD AIDS. 2023; :9564624231154298. doi: 10.1177/09564624231154298. PubMed PMID:36702811 .
  2. Chambers, C, Deeks, SL, Sutradhar, R, Cox, J, de Pokomandy, A, Grennan, T et al.. Vaccine effectiveness against 12-month incident and persistent anal human papillomavirus infection among gay, bisexual, and other men who have sex with men. J Infect Dis. 2023; :. doi: 10.1093/infdis/jiad005. PubMed PMID:36655513 .
  3. Klein, MB, Young, J, Ortiz-Paredes, D, Wang, S, Walmsley, S, Wong, A et al.. Virological Outcomes After Switching to Abacavir/Lamivudine/Dolutegravir Combined with Adherence Support in People Living with HIV with Poor Adherence: A Phase IV, Multicentre Randomized Prospective Open Label Study (TriiADD-CTN 286). Patient Prefer Adherence. 2022;16 :3267-3281. doi: 10.2147/PPA.S379065. PubMed PMID:36536672 PubMed Central PMC9759014.
  4. Hart, TA, Noor, SW, Tavangar, F, Berlin, GW, Skakoon-Sparling, S, Tan, DHS et al.. Crystal methamphetamine use and bacterial sexually transmitted infections (STIs) among gay, bisexual and other sexual minority men in Canada. Drug Alcohol Depend. 2023;242 :109718. doi: 10.1016/j.drugalcdep.2022.109718. PubMed PMID:36516548 .
  5. Costiniuk, CT, Singer, J, Lee, T, Langlois, MA, Arnold, C, Galipeau, Y et al.. COVID-19 vaccine immunogenicity in people with HIV. AIDS. 2023;37 (1):F1-F10. doi: 10.1097/QAD.0000000000003429. PubMed PMID:36476452 PubMed Central PMC9794000.
  6. Girometti, N, Ogoina, D, Tan, DHS, Pozniak, A, Klein, MB. Intersecting HIV and mpox epidemics: more questions than answers. J Int AIDS Soc. 2022;25 (12):e26043. doi: 10.1002/jia2.26043. PubMed PMID:36468930 PubMed Central PMC9721203.
  7. Knight, J, Tan, DHS, Mishra, S. Maximizing the impact of limited vaccine supply under different early epidemic conditions: a 2-city modelling analysis of monkeypox virus transmission among men who have sex with men. CMAJ. 2022;194 (46):E1560-E1567. doi: 10.1503/cmaj.221232. PubMed PMID:36442881 PubMed Central PMC9828961.
  8. Daroya, E, Grey, C, Lessard, D, Klassen, B, Skakoon-Sparling, S, Gaspar, M et al.. 'I did not have sex outside of our bubble': changes in sexual practices and risk reduction strategies among sexual minority men in Canada during the COVID-19 pandemic. Cult Health Sex. 2022; :1-17. doi: 10.1080/13691058.2022.2139414. PubMed PMID:36336339 .
  9. Pico-Espinosa, OJ, Hull, M, MacPherson, P, Grace, D, Gaspar, M, Lachowsky, N et al.. PrEP-related stigma and PrEP use among gay, bisexual and other men who have sex with men in Ontario and British Columbia, Canada. AIDS Res Ther. 2022;19 (1):49. doi: 10.1186/s12981-022-00473-0. PubMed PMID:36303191 PubMed Central PMC9615170.
  10. Hempel, A, Biondi, MJ, Baril, JG, Tan, DHS. Pre-exposure prophylaxis for HIV: effective and underused. CMAJ. 2022;194 (34):E1164-E1170. doi: 10.1503/cmaj.220645. PubMed PMID:36265058 PubMed Central PMC9448422.
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Affiliations & Other Activities

  • Clinician-Scientist, Department of Medicine, St. Michael’s Hospital
  • Assistant Professor, Department of Medicine, University of Toronto
  • Assistant Professor, Institute of Health Policy, Management & Evaluation, University of Toronto
  • Director, HIV Prevention Clinical Research Unit, University of Toronto
  • Affiliate Scientist, Toronto General Research Institute