Most Significant Publications

Estimation of the sexual transmissibility of HPV using novel epidemiologic designs:

Dr. Burchell’s doctoral dissertation at McGill University used novel, unique, and sophisticated methodologies to advance this field. The first to do so, Dr. Burchell used computer simulation to estimate the transmission probability [Am J Epidemiol 2006; cited >85 times]. She designed and led an innovative couple-based transmission study—The HPV Infection and Transmission among Couples through Heterosexual activity (HITCH) Cohort Study. This was the first and only study as of 2019 that restricted recruitment to newly-formed couples for the study of HPV infection. Dr. Burchell’s findings suggested that HPV is highly transmissible; were widely covered by international media; and are used globally in models estimating population health impact and cost-effectiveness of vaccination. Outputs garnered Dr. Burchell an international reputation in HPV research: >20 invitations to present and collaborate in a monograph series [Vaccine 2006, 2008, 2012; altogether cited >1200 times] and grants. Dr. Burchell was also invited to author a chapter on HPV transmission in the International Centre for Infectious Diseases’ 2017 report on “Counselling Patients About HPV Testing”. Dr. Burchell remains an active HITCH investigator, which is now a data source for trainees at the Division of Cancer Epidemiology, McGill University (where she holds an Adjunct Professor appointment). Five HITCH trainees have altogether published eight papers to date.

Mobilizing prevention efforts for bacterial STIs among HIV-positive men who have sex with men (MSM):

One of the few researchers in Canada to do so, Dr. Burchell quantified rates of testing for and infection with syphilis, gonorrhea, and chlamydia among HIV-positive MSM. This was done via a series of papers that capitalized on a data sharing agreement between Public Health Ontario Laboratories and the Ontario HIV Treatment Network [BMC Inf Dis 2013, ‘15; Sex Transm Infect 2014, 2016]. Although sexual risk factors and HIV co-infection are reported with STI case reports in surveillance statistics, these data are only available for the numerator, not the denominator, which greatly limits their interpretation for policy and practice recommendations. Dr. Burchell documented that 1 of 4 HIV-positive MSM have had syphilis and new infections occur at minimum rates of 1 gonorrhea, 1 chlamydia, and 4 syphilis cases per 100 person-years; these rates are many times higher than in the general population. Meanwhile, testing rates were considerably lower than recommended in clinical guidelines. Dr. Burchell’s findings mobilized prevention and testing efforts among men with HIV and new emphasis in the Ontario Ministry of Health’s HIV Strategy. Along with modeling projections [PloS One 2014], her findings also supported a new syphilis screening intervention study and are mobilizing active pursuit of new interventions to improve testing services within Dr. Burchell’s program and beyond.

Characterized the HIV care cascade using data from large cohort studies and population-based health administrative data:

Dr. Burchell has made significant contributions toward estimating rates of HIV care engagement along all steps of the HIV care “cascade”: diagnosis, linkage to care, retention in care, initiation of treatment, viral suppression, and prolonging life expectancy. Successful HIV care engagement minimizes disease progression, improves access to treatment for other health problems, limits onward transmission (via virologic suppression), and ultimately lowers mortality risk. This program of research began when Dr. Burchell was Director of a province-wide HIV clinical cohort, the Ontario HIV Treatment Network (OHTN) Cohort Study, while she was a Scientist at the OHTN (2010-2015). This work was carried out in close collaboration with government partners (AIDS Bureau, Ontario Ministry of Health and Long Term Care; Public Health Ontario Laboratories), thus allowing for rapid knowledge transfer and exchange with decision makers. It also involved securing a data sharing agreement with the Institute for Clinical Evaluative Sciences (ICES), allowing for linkage to population-based health administrative datasets. Even after her move to St. Michael’s Hospital, Dr. Burchell continued her collaborations with the OHTN, including supervision of 6 trainees conducting projects in this area. These activities also resulted in Dr. Burchell being invited to collaborate nationally in the CANOC Collaborating Centre, a multi-cohort collaboration of people on HIV antiretroviral treatment, where she now leads projects on cancer outcomes. Two publications are particularly notable for their impacts.

  • Dr. Burchell identified a rise in transmitted drug resistance among people who were diagnosed with HIV from 2002 to 2009 [J Antimicrobl Chem 2012]. This prompted Public Health Ontario to confirm the findings at the population level and to automate resistance testing when people have their first HIV viral load test [Labstract: HIV Baseline Genotyping, January 2014.]. This change will help to ensure that initially selected antiretroviral regimens are more likely to result in viral suppression.
  • Dr. Burchell also reported that, over time, increasing proportions of people in HIV care attain successful virologic suppression (likely due to regimen improvements and changing guidelines) but that engagement was suboptimal among younger adults, people who use drugs, and heterosexual men [JAIDS 2015]. Dr. Burchell shared results in a series of invited presentations to knowledge users in 2013-15. These findings were integrated into the Ontario Advisory Committee on HIV/AIDS (OACHA) Strategy to 2026 (

    Prevention of cervical cancer in high-risk, vulnerable populations:

    Dr. Burchell has contributed to the knowledge base regarding screening in high-risk populations, by identifying rates of screening, characterizing those who do not undergo timely screening, and trialing changes to screening practice that could improve participation. Most cases of cervical cancer occur among women who are under-screened, either because they have never been screened or because they have not attended routine screening. Underscreening commonly occurs among certain populations of women adversely affected by social determinants of health, generally for reasons related to poverty, language/culture, geography, and other social determinants. Women living with HIV are also at higher risk for cervical dysplasia and cancer due to HIV’s impairment of the specific immune responses required to control HPV infection. Using data from large cohorts and population-based administrative health databases, Dr. Burchell has reported suboptimal screening uptake among women living with HIV, particularly among older women and women with male physicians [Prev Med 2018; CMAJ Open 2019]. Using data from intervention trials, she has contributed to evidence suggesting that offer of self-sampling for HPV testing could improve screening uptake among rural and Indigenous women [J Women Health 2016; BMJ Open 2016].

    Current Projects

    The burden of cancer and the role of engagement in HIV care in mitigating cancer risk in people living with HIV in Ontario

    Keywords: Access to Health Care, Cancer Screening, HIV/Sexually Transmitted and Blood-Borne Infections
    Investigators: Dr. Ann Burchell Principal Investigator, Ioana Nicolau Co-principal Investigator Co-investigators: Dr. Tony Antoniou (St. Michael’s Hospital), Dr. Jennifer Brooks (University of Toronto), Dr. Curtis Cooper (Ottawa Hospital), Dr. Michelle Cotterchio (Cancer Care Ontario), Dr. Claire Kendall (Bruyere Research Institute), Dr. Abigail Kroch (OHTN), Jennifer Gillis (University of Toronto), Joanne Lindsay (St. Michael’s Hospital), Dr. Rahim Moineddin (University of Toronto), Dr. Colleen Price (Ontario Advisory Committee on HIV/AIDS), Dr. Kate Salters (BC Centre for Excellence in HIV/AIDS), Dr. Marek Smieja (McMaster University), Zak Knowles (CATIE)
    Funders: Ontario HIV Treatment Network
    Collaborators: Ontario HIV Treatment Network, CATIE, Cancer Care Ontario, ICES

    Cancer is the second-leading cause of death among people living with HIV in Ontario. HIV in and of itself is considered carcinogenic. However detailed, local information on the risk and prevalence among people with HIV in Ontario doesn’t exist.
    How many people with HIV in Ontario have been diagnosed with cancer? Which cancers are most common among people with HIV in Ontario? Could HIV care be used as a pathway and tool for cancer prevention? This kind of program for cancer prevention has never been explored.

    Gathering evidence on cancers among people living with HIV in Ontario.

    We will use existing, provincial health-research data (i.e. from the Ontario HIV Treatment Network Cohort Study, administrative health data at ICES and the Ontario Cancer Registry), to calculate cancer incidence, prevalence and mortality among people with HIV, and compare these numbers to the general population of Ontario.

    We will then examine the role of HIV care and how it affects HIV viral load and immune function to reduce cancer risk and improve patients’ general health and well-being.

    We’ll use our findings to help plan effective cancer-prevention and care strategies in Ontario and help guide the development of more holistic and effective HIV-care programs.

    Bringing bacterial STIs (sexually transmitted infections) to the agenda for comprehensive sexual health care: Community-directed interventions to facilitate testing among men who have sex with men

    Keywords: HIV/Sexually Transmitted and Blood-Borne Infections, Screening
    Investigators: Dr. Ann Burchell Principal Investigator, Ryan Lisk (ACT), Principal Investigator, Co-investigators: Dr. Darrell Tan, Jean Bacon (Ontario HIV Treatment Network), Dr. Jason Brunetta (Maple Leaf Medical Clinic Toronto), Dr. Mark Gilbert (BC Centre for Disease Control Vancouver), Dr. Dionne Gesink (University of Toronto), Ramandip Grewal (MAP Centre for Urban Health Solutions, Unity Health Toronto), Dr. Charlie Guiang (St. Michael’s Hospital, Hassle Free Clinic), Michael Kwag (Canadian AIDS Treatment Information Exchange), Dr. Carmen Logie (University of Toronto), Leo Mitterni (Hassle Free Clinic Toronto,) Dr. Rita Shahin (Toronto Public Health)
    Staff: Dr. Anna Yeung Research Coordinator, Jayoti Rana Research Coordinator
    Funders: Canadian Institutes of Health Research
    Collaborators: ACT

    In Canada, rates of bacterial sexually transmitted infections (STI) – specifically, syphilis, gonorrhea and chlamydia – among men who have sex with men have increased substantially over the past decade. The majority of cases occur in Toronto. Left untreated, serious consequences can develop such as neurosyphilis, an increased risk of HIV transmission and painful inflammation and bleeding in the rectum.

    Data shows that not enough men in Toronto who have sex with men are getting the STI testing and treatment that they need.
    Improving and increasing testing for bacterial STIs among men who have sex with men in Toronto.

    What would make it easier for men who have sex with men to get tested for bacterial STIs?

    To find out, we reviewed the scientific literature to identify potential options for increasing testing. We also got feedback on testing barriers and facilitators from gbMSM (gay, bisexual and other men who have sex with men) via focus groups, and health-care providers via an online survey.

    To adapt and refine options to improve testing, we will present the options we gathered to both the gbMSM community and healthcare providers in separate “e-Delphi Panels.” Delphi studies use several rounds of surveys to build consensus to inform the development of an intervention. For our studies, the panels will tell us what they think are the best option(s) for improving testing.

    Early results have identified eight potential solutions that address local needs and show promise getting more tests to more men who have sex with men in Toronto. For example, testing needs to be more streamlined and integrated into ongoing care for sexually active men. Examples include routine testing, online testing, nurse-led testing, and express-testing clinics that allow patients to collect their own samples. Client-targeted as well as provider-targeted reminders, online education and test-booking, as well as provider audit and feedback have the potential to improve access or delivery of STI testing.

    The literature review and focus groups/survey also revealed that effective STI testing interventions need to overcome stigma by being person-centered, sex-positive and LGBT-affirming.

    Next, we will conduct another e-Delphi study to build consensus on which of these eight solutions have the greatest potential for improving STI testing services for men who have sex with men in Toronto. These findings will be used along with community input to improve access and delivery of STI testing, enable early treatment and prevent further transmission of bacterial STIs.

    Engage-HPV: Human papillomavirus prevention for gay, bisexual and other men who have sex with men in Vancouver, Toronto and Montreal

    This project is part of the Engage Cohort Study, a sexual-health study of 2,440 men who self-identify as gbMSM in Vancouver, Toronto and Montreal.

    Keywords: HIV/Sexually Transmitted and Blood-borne Infections, Cancer Screening
    Investigators: Dr. Ann Burchell Principal Investigator, Dr. Joseph Cox (McGill University), Principal Investigator, Dr. Alexandra De Pokomandy (Research Institute of the McGill University Health Centre), Principal Investigator, Dr. Troy Grennan (B.C. Centre for Disease Control), Principal Investigator, Dr. Trevor Hart (Ryerson University), Principal Investigator, Dr. Gilles Lambert (Institut national de santé publique du Québec), Principal Investigator, Dr. David Moore (University of British Columbia), Principal Investigator
    Co-investigators: Dr. Rosane Nisenbaum (Unity Health Toronto), Dr. Darrell Tan (Unity Health Toronto), Dr. Marc Brisson (Université Laval), Dr. Francois Coutlee (Centre hospitalier de l’Université de Montréal), Dr. Shelley Deeks (Ontario Agency for Health Protection and Promotion), Dr. Eduardo Franco (McGill University), Dr. Daniel Grace (University of Toronto), Ramandip Grewal (Unity Health Toronto), Jody Jollimore (Community-Based Research Centre), Dr. Nathan Lachowsky (University of Victoria), Dr. Gina Ogilvie (University of British Columbia), Dr. Chantal Sauvageau (Institut national de santé publique du Québec) ,
    Staff: Dr. Anna Yeung (Research Coordinator), Catharine Chambers (PhD Student), Ramandip Grewal (PhD Student)
    Funders: CIHR Foundation Grant to Dr. Ann Burchell, Canadian Immunization Research Network, CIHR Institute of Cancer Research
    Collaborators: Rézo (Quebec), Gay Men’s Sexual Health Alliance, AIDS Committee of Toronto

    Gay, bisexual, and other men who have sex with men (gbMSM) are at higher risk for cancers and other diseases caused by the human papillomavirus (HPV), compared to the general population. The Provinces of British Columbia, Ontario and Quebec offer publicly funded HPV vaccine to high-risk men, including men who have sex with men – but only those who are age 26 and under. For older men, the HPV vaccine must be covered by extended-health insurance or be paid out of pocket.

    Based on clinical trials, the HPV vaccine should protect against persistent HPV infection about 60% of the time in young, healthy men who have limited sexual experience.

    How well are HPV-vaccination programs working to reduce and prevent HPV-associated diseases among men who have sex with men?
    To find out, we will:

    • Find out what proportion of gbMSM are infected with HPV in their anal and oral tracts.
    • Monitor HPV vaccine uptake among gbMSM.
    • Identify which gbMSM are more likely to be vaccinated (or willing to be vaccinated) with HPV vaccine, according to their demographic characteristics or sexual exposures.
    • Estimate how well the vaccine works against persistent HPV infection, a surrogate marker for HPV-associated cancers.
    • Predict the impact of current and alternative vaccination strategies using economic analysis and mathematical modelling.

    As part of the large, multi-city Engage Cohort Study, gbMSM complete a sexual-health survey every six months to tell us about their HPV vaccination history. Every 12 months, men also self-collect oral and anal specimens for HPV testing that will allow us to detect up to 36 different HPV types.

    Our study will provide critically needed information about how common HPV disease is among gbMSM in Canada, and the effectiveness of provincial, targeted vaccination programs for high-risk males in Canada. We will share these findings and work with public-health experts, clinicians, and community members to design HPV-prevention programs that better serve and protect gbMSM.

    Enhanced syphilis screening among HIV-positive men (ESSAHM)

    Keywords: HIV/Sexually Transmitted and Blood-borne Infections, Access to Medications, Screening
    Investigators: Dr. Ann Burchell (Principal Investigator), Dr. Darrell Tan (Principal Investigator), Dr. Vanessa Allen (Public Health Ontario, Principal Investigator)
    Co-investigators: Dr. Sharmistha Mishra (Unity Health Toronto), Dr. Sean B. Rourke (Unity Health Toronto), Dr. Nisha Andany (Sunnybrook Health Sciences Centre), Dr. Curtis Cooper (The Ottawa Hospital), Dr. David Fisman (University of Toronto), Dr. Sandra Gardner (Baycrest Health Science), Dr. Mark Gilbert (BC Centre for Disease Control), Dr. Kevin Gough (St. Michael’s Hospital), Dr. Paul MacPherson (The Ottawa Hospital), Dr. Janet Raboud (University Health Network), Dr. Anita Rachlis (Sunnybrook Health Sciences Centre), Dr. Sharon Walmsley (University Health Network)
    Staff: Ramandip Grewal, Research Coordinator
    Funders: Canadian Institutes of Health Research, Canadian HIV Trials Network
    Collaborators: Medical Outpatient Clinic at Sunnybrook Health Sciences Centre, Immunodeficiency Clinic at The Ottawa Hospital, Positive Care Clinic at St. Michael’s Hospital, Immunodeficiency Clinic at Toronto General Hospital, Public Health Ontario Laboratories, Ontario HIV Treatment Network, Dr. Jonathan Angel (Ottawa Hospital), Dr. Tony Mazzulli (Public Health Ontario), Dr. Irving Salit (University Health Network)

    Syphilis is on the rise among HIV-positive men who have sex with men in Ontario. Untreated syphilis may lead to serious problems such as neurosyphilis, can be spread to sexual partners, and can increase the likelihood of spreading HIV from one person to another. Early treatment, on the other hand, is simple, effective and inexpensive.

    A solution to make it easier for HIV-positive men to get tested for syphilis.

    We are working with four Ontario clinics to see opt-out syphilis testing incorporated whenever men in HIV care undergo HIV viral load testing, which typically occurs every three to six months. ‘Opt-out’ means that the test is a routine part of the patient’s clinic visit, unless a patient requests otherwise. The goal of this solution is to ensure that more HIV-positive men get screened for syphilis more often, increasing the chances of better outcomes through early treatment.

    We used a cluster-randomized, stepped-wedge design to introduce the testing strategy across four urban HIV clinics in Toronto and Ottawa, and then analyzed the data from participating patients’ lab results, medical charts and information. Over 30 months, enhanced screening will be applied to roughly 3,100 patients.

    Our program-science approach involving researchers and knowledge users will guide policy and practice decisions regarding scale-up in these and other HIV clinics in Ontario. Our results will also be important addition to the literature on what kinds of policies, practices and strategies really work to control the spread of syphilis among men who have sex with men, and prevent serious syphilis-related disease. Our learnings may also be applicable to other sexually transmitted and blood-borne infections that pose risk for HIV-positive men.

    Advancing evidence-based HPV vaccination & screening delivery for men who have sex with men and people living with HIV

    Investigators: Dr. Ann Burchell (Principal Investigator), Dr. Aisha Lofters, Dr. Sean B. Rourke, Dr. Darrell Tan, Dr. David Brennan, (University of Toronto), Dr. Alexandra de Pokomandy (McGill University), Jennifer Gillis (University of Toronto), Dr. Daniel Grace (University of Toronto), Dr. Troy Grennan (BC Centre for Disease Control), Dr. Trevor A. Hart (Ryerson University), Dr. Claire Kendall (University of Ottawa), Joanne Lindsay (St. Michael’s Hospital), Dr. Mona Loutfy (Women’s College Hospital), Dr. Paul MacPherson (The Ottawa Hospital), Dr. Irving Salit (Toronto General Hospital), Ramandip Grewal (St. Michael’s Hospital), Dr. Anna Yeung (St. Michael’s Hospital)
    Staff: Ashley Mah (Research Coordinator), Jayoti Rana (Research Coordinator), Lane Bonertz (Community Investigator)
    Funders: Canadian Institutes of Health Research (CIHR)
    Collaborators: Jean Bacon (Ontario HIV Treatment Network), Dr. Charlie B Guiang (St. Michael’s Hospital, Hassle Free Clinic), Dr. Shelley Deeks (Public Health Ontario), Ron Rosenes (Rosenes Consulting)

    Three-quarters of all people in Canada will be exposed to the human papillomavirus (HPV) at least once in their lifetime. While some types of HPV are low risk, other strains cause cervical, anal, and oral cancers.

    Vaccines and screening programs to prevent HPV-related cancers are available in Canada, but they’re not easy for everyone to access.

    Two populations at particularly high risk of HPV are:

    • Gay, bisexual and other men who have sex with men (gbMSM). HPV is very common among gbMSM, impacting 78-98% of this population. Although several Canadian jurisdictions, including Ontario, have a targeted HPV vaccine policy for gbMSM aged 9-26, this requires a young man to be aware of his sexual orientation, and to be willing to disclose it to a provider.
    • Men and women living with HIV infection. Research shows that this group is not getting the HPV-related cancer screening they need. The rate of anal cancer among HIV+ gbMSM is 100 times higher than in the general population. Only half of women living with HIV in Ontario undergo regular cervical cancer screening.

    How can we make it easier for high-risk groups to access HPV vaccination and screening for HPV-related cancers?

    Using a community-based perspective, this project will generate solutions by gathering and integrating scientific as well as community knowledge:

    • Searching the scientific literature: We have synthesized findings and recommendations from eight recent research studies about HPV vaccine uptake and willingness, HPV awareness, and screening for HPV-related cancers.
    • Consulting with the community: We brought the evidence we gathered to health/service providers and people with lived expertise, to discuss, listen and acknowledge concerns. We then gathered ideas and advice from this community, looking for innovative ideas, alternatives and recommendations for policy and practice.