[3][4] During the Severe acute respiratory syndrome (SARS) crisis in 2003, TPH under then medical officer of health Dr. Sheela Basrur lead the City of Toronto's response to the virus.

As a result of SARS, TPH "totally reorganized itself", with a stronger liaison unit with acute-care facilities and changes being made to better address public health on a provincial and federal level.

On January 7, 2020, TPH was informed of a "undiagnosed viral pneumonia" in Wuhan, China, and began to monitor and develop a response plan should it spread to Toronto.

[8] TPH collaborated with the University of Toronto to interpret self-reported symptom data provided by the COVID Near You platform, based out of Harvard Medical School and Boston Children's Hospital.

[11] On September 11, 2020, the Public Health Agency of Canada announced $13.9 million in funding for TPH to establish a "voluntary self-isolation centre" for eligible residents facing "difficulty properly isolating themselves.