COVID-HIV Evaluation of Serology & Health Services (CHESS Study)

In Progress


HIV/Sexually Transmitted and Blood-borne Infections


HIV affects the immune system’s ability to respond to infections and shares some of the same risk factors as COVID-19, such as older age, existing health concerns, and lower income. However due to limited testing and research, we do not yet know how many people living with HIV have been infected with COVID-19, and if they experience worse health outcomes than the general population if they do become infected.

We also do not yet know if people living with HIV will have a different antibody response to SARS-CoV-2 following natural infection or vaccination compared to those not living with HIV. It is not clear whether certain individuals will require higher doses or additional booster shots of the COVID-19 vaccine, depending on the current state of their immune system


Instructions for Dried Blood Spot Collection

See PDF of the instructions for dried blood spot collection here.

How has COVID-19 impacted the health of people living with HIV in Ontario?

This study seeks to address these gaps in knowledge, by looking at:

  1. The proportion of people living with HIV in Ontario who have been infected with or vaccinated against the COVID-19 virus since the beginning of the pandemic. We will invite people living with HIV who are part of the Ontario HIV Treatment Network (OHTN) Cohort Study to collect a finger prick of blood at home, which will be tested for antibodies to SARS-CoV-2, the virus that causes COVID-19.
  2. How well Canada’s current vaccines are working to protect people with HIV from COVID-19 infection. Using linked administrative health data from ICES, we will compare COVID-19 vaccine effectiveness in people living with HIV to individuals in the general population without HIV infection.
  3. How COVID-19 has affected the health of people with HIV in Ontario. To do this, we’ll analyze COVID-19-related health-care service utilization and testing/diagnoses data from ICES. Our study will provide a clearer picture of the rates, risk factors and health impacts of COVID-19 on people living with HIV to better inform decisions made in a rapidly changing pandemic. The results will contribute to urgently-needed recommendations on policies, practices, and strategies for health care, health services, and public health/vaccination strategies to better protect and serve people living with HIV.

This study is being run under the guidance of a community advisory board comprised of a broad range of people living with HIV in Ontario. This board is lead by two community co-chairs who have experience in community advocacy and involvement in research. These individuals provide community perspectives into project planning and evidence-sharing activities.

This study is partnered with the Ontario HIV Treatment Network Cohort Study (OHTN), the COVAXHIV Study ICES, and the Canadian HIV Trials Network.

World Aids Day 2021 Presentation on COVID-19 and people living with HIV by Dr. Ann Burchell


HIV/Sexually Transmitted and Blood-borne Infections

Dr. Ann Burchell

A national leader in HIV/STI research and Canada Research Chair in Sexually Transmitted Infection Prevention, Dr. Ann Burchell generates evidence for effective and practical strategies to prevent STIs and related cancers in high-risk populations, including people living with or at risk for HIV.


  • Dr. Abigail Kroch (PI of Ontario HIV Treatment Network Cohort Study) Principal Investigator
  • Dr. Curtis Cooper (Ottawa Hospital Research Institute) Principal Investigator
  • Dr. Marc-André Langlois (University of Ottawa) Principal Investigator
  • Dr. Gordon Arbess (St. Michael’s Hospital)
  • Dr. Anita Benoit (University of Toronto Scarborough)
  • Dr. Sarah Buchan (Public Health Ontario)
  • Catharine Chambers (PhD Student; University of Toronto)
  • Dr. Claire Kendall (Bruyère Research Institute)
  • Dr. Jeff Kwong (Institute of Clinical and Evaluative Sciences)
  • Dr. Lawrence Mbuagbaw (McMaster University)
  • John McCullagh (Ontario AIDS Network)
  • Dr. Rahim Moineddin (University of Toronto)
  • Dr. Nasheed Moqueet (Public Health Agency of Canada)
  • Ron Rosenes (Ron Rosenes Consulting)
  • Dr. Sergio Rueda (Centre for Addition and Mental Health)
  • Dr. Vanessa Tran (Public Health Ontario)
  • Dr. Sharon Walmsley (University Health Network)
  • Darien Taylor (Ontario HIV Treatment Network)
  • Dr. Philippe El-Helou (Hamilton Health Sciences Centre)
  • Dr. Jorge Martinez-Cajas (Hotel Dieu Hospital Kingston)
  • Dr. Beatriz Eugenia Alvarado (Hotel Dieu Hospital Kingston)
  • Dr. Michael Silverman (London St. Joseph's)
  • Dr. Mona Loutfy (MLMC Maple Leaf Medical)
  • Dr. David Knox (MLMC Maple Leaf Medical)
  • Dr. Nisha Andany (Sunnybrook Hospital)
  • Dr. Jeff Cohen (Windsor Regional Hospital)


  • Dr. Anna Yeung (MAP, St. Michael's Hospital)
  • Dr. Hoda Hassan (MAP, St. Michael’s Hospital)
  • Ashley Mah (MAP, St. Michael’s Hospital)
  • Catharine Chambers (PhD Student; University of Toronto)
  • Cassandra Freitas (PhD Student; University of Toronto)


  • Canadian Institutes of Health (CIHR)
  • COVID-19 Immunity Task Force (CITF)


  • Ontario HIV Treatment Network & participating clinical sites
  • Canadian HIV Trials Network
  • ICES

Contact Info

Dr. Hoda Hassan