Ontario Public Health System

Public Health History

16 June 2020

The work of a publicly-funded healthcare system focuses on the health of individuals. The work of a public health system focuses on the health of populations (communities).

The work of public health happens primarily behind the scenes. In fact, most Ontarians likely don’t realize the extent to which the work of public health impacts their lives every day. Public health interventions protect people from infectious diseases and environmental threats to their health, make the food they eat safer, and help to better support and inform their choices about risks. Public health also impacts populations by promoting social conditions that improve health and supporting the development of healthier built environments (e.g., bike-friendly, walkable).

How does the public health system in Ontario work?

Ontario’s public health system is comprised of a variety of organizations that all work together collaboratively to have the impact described above.

Ministry of Health

Ontario’s Ministry of Health (the Ministry) sets the strategic directions and priorities for Ontario’s health system, including both health care and public health. To help achieve those directions and priorities, it develops and enforces legislation, regulations, standards, policies and directives.
The Ministry monitors and reports on the health system and the health of Ontarians. It then works to improve the health of the population and the province’s health system. It works to improve access to care, deliver community care, and educate Ontarians about health decisions. It provides funding to the health system and monitors to ensure that the system meets the needs of Ontarians and is sustainable.

Ontario’s Chief Medical Officer of Health
Within the Ministry, the Office of Chief Medical Officer of Health is responsible for determining provincial public health needs, developing public health initiatives and strategies, and monitoring public health programs delivered by Ontario’s local public health units (described below). Ontario’s public health programs focus on disease prevention and control, screening for health conditions, and public education on health matters such as communicable diseases and healthy living.

The Chief Medical Officer of Health (CMOH) reports directly to the Deputy Minister of Health. The Office of the CMOH works to ensure that appropriate actions are taken to respond to urgent and emergency situations. It engages with local, national and international partners to develop public health strategies. It advises other parts of government on the potential health impacts of government initiatives and they provide training and other supports to advance Ontario’s public health system. When needed, the Chief Medical Officer of Health has the authority to direct local jurisdictions in Ontario to implement public health actions in response to a public health risk or emergency.

Local Public Health Units

Public health units (PHU) offer healthy living and disease prevention information and programs to their communities. At the local level, they lead programs focused on the prevention and control of communicable diseases, including monitoring local data to tailor their programs to what is happening in their community.  They also provide information about and programs to encourage healthy lifestyles, including sexual health, vaccinations, substance use, mental health, and healthy growth and development.

The local medical officer of health (MOH) has the authority to enforce quarantine, business closures, and a range of other actions at the local level as well as helping to execute and enforce the measures set out by the CMOH.

Each PHU is led by an MOH. This MOH is accountable to a local board of health. Each board of health has responsibility for delivering local public health programs and services within its geographic borders. Funding for Ontario’s PHUs comes both from municipalities and from the provincial government.

Public Health Ontario

Public Health Ontario (PHO) is an agency of the Government of Ontario and are a key partner in Ontario’s public health system. Our expertise spans the following areas: chronic disease prevention, emergency preparedness, environmental and occupational health, health promotion, injury prevention, infectious disease and microbiology. With this expertise, we:

  • work closely with the Ministry, the Office of the Chief Medical Officer of Health, and the local PHUs – providing them with scientific and technical information and advice to guide their decisions and actions
  • provide critical laboratory testing – conducting more than 6 million tests every year for public health units, hospitals, and physicians
  • monitor the health of Ontario’s population and support local PHUs with this type of monitoring for their local populations
  • provide education and professional development to Ontario’s health providers and organizations
  • conduct public health research
  • provide advice and operational support in emergency or outbreak situations with health implications

It takes many partners, working together, to help Ontarians live healthier lives. We link public health practitioners, front-line health care workers and researchers to the best scientific knowledge from around the world.

Partnerships and Collaboration

Because health is influenced by such a wide range of factors, public health is a field that requires the collaboration of many levels of government, healthcare and academic institutions, community organizations, and partners from the education, labour, law enforcement, and a wide variety of other sectors.

Because Ontario is part of a globally connected world, it is essential for Ontario’s public health system to coordinate with others across jurisdictions. This means close collaboration with partners in public health in other provinces and territories and with the federal level, through the Public Health Agency of Canada (PHAC), and, through PHAC, the World Health Organization (WHO).


PHO Rounds: Update on Ontario's new tick-borne diseases of public health significance

This PHO Rounds will provide an epidemiological summary of the first year of these diseases being reportable in Ontario.

See the Event Details
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Updated 16 June 2020