Darrell Tan


Scientist, Li Ka Shing Knowledge Institute


Dr. 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. Knox, DC, Anderson, PL, Harrigan, PR, Tan, DH. Multidrug-Resistant HIV-1 Infection despite Preexposure Prophylaxis. N. Engl. J. Med. 2017;376 (5):501-502. doi: 10.1056/NEJMc1611639. PubMed PMID:28146652 .
  2. Tan, DH, Raboud, J, Szadkowski, L, Szabo, E, Hu, H, Wong, Q et al.. Novel imaging modalities for the comparison of bone microarchitecture among HIV+ patients with and without fractures: a pilot study. HIV Clin Trials. 2017;18 (1):28-38. doi: 10.1080/15284336.2016.1266074. PubMed PMID:27951753 .
  3. MacFadden, DR, Tan, DH, Mishra, S. Optimizing HIV pre-exposure prophylaxis implementation among men who have sex with men in a large urban centre: a dynamic modelling study. J Int AIDS Soc. ;19 (1):20791. . PubMed PMID:27665722 PubMed Central PMC5035769.
  4. Money, DM, Moses, E, Blitz, S, Vandriel, SM, Lipsky, N, Walmsley, SL et al.. HIV viral suppression results in higher antibody responses in HIV-positive women vaccinated with the quadrivalent human papillomavirus vaccine. Vaccine. 2016;34 (40):4799-806. doi: 10.1016/j.vaccine.2016.08.016. PubMed PMID:27544584 .
  5. Wilton, J, Kain, T, Fowler, S, Hart, TA, Grennan, T, Maxwell, J et al.. Use of an HIV-risk screening tool to identify optimal candidates for PrEP scale-up among men who have sex with men in Toronto, Canada: disconnect between objective and subjective HIV risk. J Int AIDS Soc. 2016;19 (1):20777. . PubMed PMID:27265490 PubMed Central PMC4911732.
  6. Grewal, R, Allen, VG, Gardner, S, Moravan, V, Tan, DH, Raboud, J et al.. Serosorting and recreational drug use are risk factors for diagnosis of genital infection with chlamydia and gonorrhoea among HIV-positive men who have sex with men: results from a clinical cohort in Ontario, Canada. Sex Transm Infect. 2017;93 (1):71-75. doi: 10.1136/sextrans-2015-052500. PubMed PMID:27154185 PubMed Central PMC5293859.
  7. Burchell, AN, Allen, VG, Grewal, R, MacPherson, PA, Rachlis, A, Walmsley, S et al.. Enhanced syphilis screening among HIV-positive men (ESSAHM): a study protocol for a clinic-randomized trial with stepped wedge design. Implement Sci. 2016;11 :8. doi: 10.1186/s13012-016-0371-0. PubMed PMID:26772390 PubMed Central PMC4715363.
  8. Tan, DH, Szadkowski, L, Raboud, J, Yi, TJ, Shannon, B, Kaul, R et al.. Effect of Intercurrent Infections and Vaccinations on Immune and Inflammatory Biomarkers Among Human Immunodeficiency Virus-Infected Adults on Suppressive Antiretroviral Therapy. Open Forum Infect Dis. 2015;2 (2):ofv036. doi: 10.1093/ofid/ofv036. PubMed PMID:26380337 PubMed Central PMC4567101.
  9. Burchell, AN, Allen, VG, Gardner, SL, Moravan, V, Tan, DH, Grewal, R et al.. High incidence of diagnosis with syphilis co-infection among men who have sex with men in an HIV cohort in Ontario, Canada. BMC Infect. Dis. 2015;15 :356. doi: 10.1186/s12879-015-1098-2. PubMed PMID:26289937 PubMed Central PMC4546079.
  10. Yoong, D, Naccarato, M, Sharma, M, Wilton, J, Senn, H, Tan, DH et al.. Preparing for pre-exposure prophylaxis: perceptions and readiness of Canadian pharmacists for the implementation of HIV pre-exposure prophylaxis. Int J STD AIDS. 2016;27 (8):608-16. doi: 10.1177/0956462415589896. PubMed PMID:26025254 .
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Affiliations & Other Activities

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