In several emergency departments throughout Canada, the rapid spread of the flu is contributing to overcrowding as both children and adults are experiencing prolonged fevers. The most recent federal report indicates a slight decrease in flu activity nationwide.
According to the Public Health Agency of Canada, for the week ending on December 27, 2025, 33.3% of tests came back positive for the flu, marking the highest rate in the past three seasons. As of January 3, a federal snapshot indicated flu positivity at 27.1%. Areas in British Columbia, Alberta, Ontario, Quebec, and Prince Edward Island have reported widespread influenza activity.
The current surge in flu cases is driven by the H3N2 subclade, known as K, which has mutations that do not seem to result in more severe illness, as per the World Health Organization. While there may be some mismatch in the flu shot components targeting this year’s strains, experts emphasize that the vaccine still provides protection against other flu subtypes and helps prevent severe outcomes such as hospitalizations across all age groups.
The early and significant increase in flu cases this season has led to a surge in admissions at North York General Hospital in Toronto. Dr. Kevin Wasko, the hospital’s chief of emergency medicine, mentioned that the hospital is operating at full capacity, resulting in admitted patients waiting in the emergency department for available beds.
Meanwhile, Public Health Ontario reported a decline in flu activity over the past two weeks, indicating that the peak occurred in mid-December 2025. Dr. Wasko 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.
In southwestern Ontario, the Erie Shores emergency department observed shorter wait times compared to North York but noted a trend of more children being affected this year. Dr. Braedon Hendy, chief of emergency medicine at Erie Shores Healthcare, mentioned an increase in admissions for influenza type A, particularly with more severe cases in pediatric patients.
The flu has impacted individuals of all ages, with symptoms ranging from fever, cough, and fatigue to severe illness requiring medical intervention like intubation. Notably, children have been experiencing longer fevers and gastrointestinal symptoms with the current flu strain.
Health officials have highlighted the importance of vaccination to combat the flu, especially as the predominant strain, H3N2, has not circulated widely in recent seasons. Monitoring of wastewater in Ontario aligns with the clinical flu picture, with subclade K being the dominant strain. Researchers are awaiting the latest wastewater data to confirm trends following holiday gatherings.
The situation remains dynamic, and ongoing monitoring and preventative measures are crucial as healthcare facilities strive to manage the impact of the flu season effectively.