Darrell Tan

MD, FRCPC, PhD

Scientist

Biography

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. Hurst, JR, Tan, DHS, Li, A, Khera, SS, Persaud, R, Chan, A et al.. Monkeypox virus transcriptional profiles and host responses in skin lesion swabs among individuals with HIV. J Infect Dis. 2025; :. doi: 10.1093/infdis/jiaf316. PubMed PMID:40498594 .
  2. Ajiboye, W, Tharao, W, Owino, M, Soje, L, Tian, JMLH, Ly, A et al.. Racial disparities in HIV pre-exposure prophylaxis (PrEP) awareness and uptake among white, Black, and Indigenous men in Canada: Analysis of data from the I'm Ready national HIV self-testing study. Can J Public Health. 2025;116 (2):243-253. doi: 10.17269/s41997-025-01009-5. PubMed PMID:40106208 PubMed Central PMC12075050.
  3. Monti, EB, Penichet, D, Rudd, M, Yoong, D, Pathan, SS, Moin, A et al.. Hepatitis B prevention interventions during HIV post-exposure prophylaxis visits: A retrospective chart review. Int J STD AIDS. 2025;36 (7):550-557. doi: 10.1177/09564624251325312. PubMed PMID:40072487 .
  4. Tharao, W, Nyoni, T, Daftary, A, Bullock, S, Blot, S, Pierre-Pierre, V et al.. Post-arrival HIV acquisition patterns: Insights from African, Caribbean, and Black immigrant communities in Canada. Can J Public Health. 2025;116 (2):194-208. doi: 10.17269/s41997-024-00991-6. PubMed PMID:39994149 PubMed Central PMC12076988.
  5. Skakoon-Sparling, S, Chow, S, Palma, PA, Adam, B, Elkington, N, Dvorakova, M et al.. Social-support buffers the effect of internalized homonegativity on intrusive sexual thoughts/behaviors. Health Psychol. 2025;44 (7):725-733. doi: 10.1037/hea0001468. PubMed PMID:39964435 .
  6. Khera, SS, Mishra, S, Pico Espinosa, OJ, Gough, K, Tan, C, Walmsley, S et al.. Early clinical experience using tecovirimat during the 2022 mpox epidemic in Toronto underscores ongoing clinical equipoise and the need for randomized trials. J Antimicrob Chemother. 2025;80 (4):935-940. doi: 10.1093/jac/dkaf010. PubMed PMID:39960082 PubMed Central PMC11962370.
  7. McGarrity, MW, Lisk, R, MacPherson, P, Knox, D, Woodward, KS, Reinhart, J et al.. Hepatitis C Virus Seroprevalence, Incidence, and Screening Patterns in Ontario Preexposure Prophylaxis Users. Open Forum Infect Dis. 2025;12 (1):ofaf014. doi: 10.1093/ofid/ofaf014. PubMed PMID:39877400 PubMed Central PMC11773187.
  8. Xiu, F, Doyle, CM, Anato, JLF, Knight, J, Wang, L, Cox, J et al.. Impact of interventions on mpox transmission during the 2022 outbreak in Canada: a mathematical modeling study of three different cities. Int J Infect Dis. 2025;153 :107792. doi: 10.1016/j.ijid.2025.107792. PubMed PMID:39848438 .
  9. McGarrity, MW, MacPherson, P, Li, A, Naccarato, M, Anderson, P, Tan, DHS et al.. Intracellular tenofovir-diphosphate concentrations in HIV pre-exposure prophylaxis users who underwent bariatric surgery. HIV Med. 2025;26 (4):643-649. doi: 10.1111/hiv.13759. PubMed PMID:39812218 PubMed Central PMC11970351.
  10. Tan, DHS, Antinori, A, Eu, B, Galindo Puerto, MJ, Kinder, C, Sweet, D et al.. Weight and Metabolic Changes With Long-Acting Cabotegravir and Rilpivirine or Bictegravir/Emtricitabine/Tenofovir Alafenamide. J Acquir Immune Defic Syndr. 2025;98 (4):401-409. doi: 10.1097/QAI.0000000000003584. PubMed PMID:39676239 PubMed Central PMC11841724.
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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