The Ontario HIV Epidemiology and Surveillance Initiative

Better access to timely, relevant, comprehensive information about
the epidemiology of HIV in Ontario.

What is OHESI?

Download the OHESI fact sheet in PDF format.
View the video presentation.

OHESI is a new provincial collaboration between agencies involved with HIV epidemiology and surveillance in Ontario.

The overall purpose of this new initiative is to contribute to achieving the vision, mission and goals of Ontario's HIV/AIDS Strategy to 2025: Changing the course of the HIV prevention, engagement, and care cascade. In support of the strategy, the objectives of the OHESI are to understand, monitor and translate the epidemiology of HIV in the province of Ontario, in order to:


Understand the challenges along the prevention, engagement and care cascade.


Inform local and provincial policies and programs such that services can adjust to meet changing needs.


Provide the information needed to develop, implement and evaluate strategies and interventions, and integrate evidence into practice.


Monitor the provincial progress in achieving the goals of the strategy.

Who's involved?

Why was OHESI created?

By working together, the agencies involved with OHESI are aiming to achieve better access to timely, relevant, and comprehensive information about the epidemiology of HIV in Ontario, and to disseminate this information more widely to the different groups of stakeholders who need to know it, including:

People living with or at risk of HIV, AIDS service organizations and funded programs, Local Health Information Networks, Public Health Units and Community Health CEntres, Policy and decision-makers, Clinicians, clinics and other service providers delivering care for people with HIV, Laboratories, Researchers, General public and the media

How will OHESI do this?

OHESI's activities will reflect the conceptual frameworks of the provincial strategy, namely syndemic theory and the integrated HIV prevention, engagement and care cascade. Using HIV epidemiology and surveillance data related to these frameworks, the primary emphasis of OHESI will be on the following populations affected by HIV in Ontario:

People living with HIV/AIDS

Gay, bisexual and other men who have sex with men

African, Caribbean and Black communities, including people from HIV-endemic countries

Indigenous men and women

Men and women who use drugs

At-risk women

For example, this may include for a given population:

1. Drawing on HIV testing and viral load data to describe testing uptake, diagnosis, linkage, retention in care and suppressed viral load
2. Presenting alongside research data which looks at underlying determinants (e.g. behavioural measures, socioeconomic status)
3. Combining these with modeled estimates of HIV incidence and prevalence

When will the information be available?

Currently, the partnering agencies are working together to establish the foundation needed to generate the information needed, including determining the right strategies for monitoring and translating the epidemiology of HIV in Ontario for key stakeholders. Our goal is to expand this website into an online knowledge hub for relevant provincial HIV epidemiology and surveillance information.

We will post reports and analyses as they become available on our reports page.

Join our mailing list to be notified of updates


For more information contact Abigail Kroch, Applied Epidemiology Unit, Ontario HIV Treatment Network:

extension 2306