Several emergency departments in Canada are facing overcrowding due to the rapid spread of the flu, resulting in prolonged fevers for both children and adults. The latest federal report indicates a slight decrease in flu activity nationwide, with 33.3% of tests being positive for the week ending December 27, 2025, marking the highest value in the last three seasons according to the Public Health Agency of Canada. A federal snapshot released on January 3 showed flu positivity at 27.1%.
Influenza activity is prevalent in various regions of Canada, including British Columbia, Alberta, Ontario, Quebec, and Prince Edward Island. The current surge is primarily driven by the H3N2 subclade known as K, with mutations that do not appear to cause more severe illness, as per the World Health Organization.
Although some components of this year’s flu shot may not be perfectly matched to the circulating strains, health experts emphasize that the vaccine still provides protection against other flu subtypes and helps prevent severe outcomes like hospitalizations across all age groups.
The early and intense flu season has led to a surge in admissions at North York General Hospital in Toronto, with many patients awaiting beds in the emergency department. Public Health Ontario reported a decline in flu activity over the past two weeks, indicating a peak during the week of December 14-20, 2025.
Dr. Kevin Wasko, Chief of Emergency Medicine at North York General Hospital, highlighted the strain on the healthcare system due to the influx of flu cases but encouraged individuals in need of medical attention not to hesitate to seek help.
Further south in Ontario, Erie Shores Healthcare has seen shorter wait times compared to North York but noted an increase in pediatric flu cases. Dr. Braedon Hendy, Chief of Emergency Medicine at Erie Shores Healthcare, mentioned the rise in severity among pediatric patients and the prolonged fevers observed in children during this flu season.
In Newfoundland, health officials reported more children experiencing longer fevers and gastrointestinal symptoms due to the flu. Pediatric infectious disease specialists emphasized the lack of exposure to the H3N2 strain among children in recent years.
Wastewater testing in Ontario aligns with the clinical picture of influenza, showing subclade K as the dominant strain. Researchers are monitoring the latest wastewater data to confirm the trend following the holiday gatherings, aiming to assess the impact of the flu on the population.