Theresa Tam is a Canadian physician and public health leader best known for serving as Canada’s Chief Public Health Officer from 2017 to 2025. With a background in pediatric infectious diseases and epidemiology, she has spent decades working on infectious disease prevention, immunization, emergency preparedness, and public health policy. Her profile became especially prominent during the COVID-19 pandemic, when she played a central role in communicating health information and supporting Canada’s national public health response. However, her career extends well beyond the pandemic, including work on major infectious disease emergencies and global health initiatives.
Theresa Tam Biography Table
| Biography Detail | Information |
| Full Name | Dr. Theresa Tam |
| Born | 1965 |
| Birthplace | Hong Kong |
| Nationality | Canadian |
| Profession | Physician & Public Health Specialist |
| Medical Specialty | Pediatric Infectious Diseases |
| Medical Degree | University of Nottingham, United Kingdom |
| Pediatric Training | University of Alberta |
| Infectious Disease Training | University of British Columbia |
Who Is Theresa Tam?
Dr. Theresa Tam is a Canadian physician and public health specialist who served as Canada’s Chief Public Health Officer (CPHO) from June 2017 until June 2025. She is a pediatric infectious disease specialist whose professional work has focused on immunization, infectious diseases, emergency preparedness, health equity, and global health security.
Tam became widely known across Canada during the COVID-19 pandemic, when she served as one of the country’s leading public health voices. In that role, she provided health guidance and communicated information about the evolving pandemic, vaccination, and other public health measures.
Her career, however, extends well beyond COVID-19. Before becoming CPHO, she held senior positions at the Public Health Agency of Canada (PHAC) and contributed to Canada’s responses to several infectious disease emergencies.
Early Life and Medical Education
Theresa Tam was born in Hong Kong in 1965 and later grew up in the United Kingdom. She studied medicine at the University of Nottingham, where she earned her medical degree in 1989.
After moving to Canada, she continued her medical training. She completed a pediatric residency at the University of Alberta and later undertook specialized training in pediatric infectious diseases at the University of British Columbia.
Tam also completed the Canadian Field Epidemiology Program, which provided additional preparation in population health, disease surveillance, and outbreak investigation. She became a Fellow of the Royal College of Physicians and Surgeons of Canada.
This combination of clinical medicine and public health training became an important part of her later career.
Theresa Tam’s Career in Public Health
Before becoming Canada’s Chief Public Health Officer, Tam held several senior positions within the Public Health Agency of Canada.
Her work included infectious disease prevention and control, immunization, communicable disease surveillance, emergency preparedness, laboratory biosafety, and biosecurity. She also served as Deputy Chief Public Health Officer and Assistant Deputy Minister for Infectious Disease Prevention and Control.
Over the course of her public health career, Tam was involved in Canada’s response to several major health emergencies. These included:
- Severe acute respiratory syndrome (SARS)
- Pandemic influenza H1N1
- Ebola
- Mpox
- COVID-19
She also participated in international public health work, including activities connected with the World Health Organization and global efforts involving infectious disease preparedness and polio eradication.
Becoming Canada’s Chief Public Health Officer
The Government of Canada appointed Theresa Tam as Chief Public Health Officer on June 26, 2017. The CPHO serves as the federal government’s lead public health professional and provides public health advice to the Minister of Health and the Public Health Agency of Canada.
Tam was the first woman to hold the position. Her responsibilities included advising on health threats, supporting public health preparedness, communicating risks to Canadians, and working with provincial and territorial health officials.
During her tenure, she also emphasized issues such as health disparities and the importance of improving health outcomes for populations experiencing greater barriers to health.
Her Role During the COVID-19 Pandemic
COVID-19 became the defining public health challenge of Tam’s tenure.
As the pandemic developed in Canada in 2020, Tam became a prominent source of information about the virus and public health recommendations. Her work involved communicating evolving scientific information while coordinating with other levels of government and public health organizations.
One of the major responsibilities during this period was supporting Canada’s vaccination campaign. Canada’s COVID-19 vaccination program became the country’s largest vaccination campaign, and Tam played a leadership role in the national public health response.
The pandemic also placed public health communication under intense public attention. Guidance changed as scientists learned more about the virus, transmission, vaccines, and emerging variants. Tam’s public appearances and statements therefore became an important part of how federal health information reached Canadians.
Her tenure also involved communicating about other pandemic-related issues, including protective measures, emerging variants, vaccination, and the continuing need to monitor infectious disease risks.
Work Beyond COVID-19
Although COVID-19 received much of the public attention surrounding Theresa Tam, her professional interests have covered a much wider range of public health issues.
Her work has included immunization programs, communicable disease surveillance, emergency management, laboratory biosafety and biosecurity, and opioid-related harms.
Health equity was another recurring theme in her public health work. In a 2018 statement outlining her priorities, Tam said reducing health disparities among key populations would be an important focus of her mandate.
Her international work has also been significant. Tam has served as an expert on World Health Organization committees and participated in international efforts related to infectious diseases and global health security.
Theresa Tam’s Approach to Public Health
Tam’s career reflects the connection between clinical medicine and population-level health protection.
A physician treating individual patients may focus on diagnosis and treatment, while public health professionals also consider how diseases spread through communities, how health systems prepare for emergencies, and how preventive measures can reduce risks across populations.
Tam’s background in pediatric infectious diseases, epidemiology, immunization, and emergency preparedness gave her experience across several of these areas.
Her public health work also placed considerable importance on evidence, surveillance, preparedness, and communication. These areas became especially visible during the COVID-19 pandemic, when health authorities had to make decisions while scientific knowledge was changing rapidly.
Awards and Recognition
Theresa Tam has received recognition for her contributions to medicine and public health.
In 2025, she was appointed an Officer of the Order of Canada. The Governor General’s citation recognized her decades of work as a pediatric infectious disease specialist and public servant, including her contributions to national and global public health and her leadership during the COVID-19 pandemic.
She also received an honorary Doctor of Laws degree from Carleton University in recognition of her career in public health and her role during Canada’s COVID-19 response.
The Canadian Public Health Association also formally recognized Tam when she concluded her tenure as Chief Public Health Officer in June 2025.
What Happened After Her CPHO Tenure?
Theresa Tam concluded her tenure as Canada’s Chief Public Health Officer on June 20, 2025, after serving in the position for almost eight years.
Her departure marked the end of a period in which the CPHO position received unusually high public visibility because of COVID-19.
Importantly, her career should not be defined only by the pandemic. Her professional background spans decades of work in infectious diseases, immunization, epidemiology, emergency preparedness, and broader public health.
Frequently Asked Questions
Who is Theresa Tam?
Theresa Tam is a Canadian physician and public health specialist. She served as Canada’s Chief Public Health Officer from 2017 to 2025 and has expertise in pediatric infectious diseases, immunization, emergency preparedness, and global health security.
When did Theresa Tam become Canada’s Chief Public Health Officer?
Tam was appointed Chief Public Health Officer on June 26, 2017.
When did Theresa Tam leave the CPHO position?
She concluded her tenure as Chief Public Health Officer on June 20, 2025.
What did Theresa Tam do during COVID-19?
Tam was one of Canada’s senior public health leaders during the COVID-19 pandemic. She helped guide the national public health response and played a leadership role in the country’s COVID-19 vaccination campaign.
Where did Theresa Tam study medicine?
She earned her medical degree from the University of Nottingham in the United Kingdom. She later completed pediatric training at the University of Alberta and pediatric infectious disease training at the University of British Columbia.
What diseases and health emergencies has Theresa Tam worked on?
Her public health career has included work involving SARS, H1N1 influenza, Ebola, mpox, and COVID-19, along with broader work in infectious disease prevention, immunization, and emergency preparedness.
Has Theresa Tam received major Canadian honours?
Yes. In 2025, she was appointed an Officer of the Order of Canada in recognition of her contributions to public health.
What is Theresa Tam’s area of medical specialization?
Tam is a pediatric infectious disease specialist. Canadian medical records list her specialties as pediatrics and infectious diseases.
Conclusion
Theresa Tam is a Canadian physician whose career has combined clinical medicine, infectious disease expertise, epidemiology, and public health leadership. Her appointment as Chief Public Health Officer in 2017 placed her at the centre of Canada’s national health system, and her visibility increased substantially during the COVID-19 pandemic.
Her broader career includes work on immunization, infectious disease surveillance, emergency preparedness, health equity, and global health security. After concluding her term as CPHO in June 2025, her professional record remained closely associated with several decades of public health service in Canada.
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