Flu Hospitalizations Nearly Double, H3N2 Most Dominant Strain: Public Health Agency of Canada

Influenza activity is high and increasing in all regions across Canada, according to the Canadian respiratory virus surveillance report lasted updated on Dec. 19, 2025, produced by the FluWatch+ surveillance program. PeopleImages.com - Yuri A/Shutterstock

Weekly flu hospitalizations nearly doubled in Canada compared to the number reported the previous week, with the influenza A (H3N2) strain being the most commonly detected among the rising number of infections, the latest Public Health Agency of Canada (PHAC) data indicates.

The number of new influenza cases detected in Canada in the week ending Dec. 13 rose by approximately 64 percent compared to the week ending Dec. 6, increasing from 7,120 new cases to 11,646 new cases, says the most recent Canadian respiratory virus surveillance report, last updated on Dec. 19.

Of the 11,646 new cases detected, 99 percent (11,577 cases) were reported to be influenza A, while 69 cases were reported to be influenza B, according to the report for influenza, produced by PHAC’s FluWatch+ surveillance system. Among the subtyped influenza A detections, 89 percent were influenza A (H3N2).

“All indicators of influenza activity are high and increasing,” the report said. “All regions throughout the country are reporting increasing influenza activity.”

The report says 44 regions across 11 provinces and territories reported influenza activity levels in the week ending Dec. 13, with “widespread” activity reported in 11 regions in five provinces: British Columbia, Alberta, Saskatchewan, Ontario, and Quebec.

The weekly rate of reported hospitalizations associated with influenza nearly doubled, from 3.9 per 100,000 population in the week ending Dec. 6 to 6.2 per 100,000 population in the week ending Dec. 13, totalling 2,134 reported hospitalizations. Hospitalizations were highest among those aged 65 years and older, with a rate of 18.4 per 100,000 population.

For those aged 18 years and younger, there have been 306 hospitalizations, 36 ICU admissions, and less than five deaths reported to be associated with influenza since Aug. 24, according to the report, citing data from the University of Calgary’s SPRINT-KIDS Project, or Surveillance Program for Rapid Identification and Tracking of Infectious Diseases in Kids.

Outbreaks are also on the rise, with 186 new influenza outbreaks reported in the week ending Dec. 13, up from 109 the previous week.

The youngest and oldest age groups reported the highest numbers of cases, with 3,553 cases attributed to those 19 years and younger, and 3,075 cases attributed to those 65 years and older.

The report says 47 people were admitted to the ICU due to influenza in the week ending Dec. 13, with a total of 136 ICU admissions related to influenza since Aug. 24. Additionally, there have been a total of 74 influenza-related deaths reported since Aug. 24.

“Seasonal influenza activity has increased globally in recent months, with an increased proportion of seasonal influenza A(H3N2) viruses being detected,” the World Health Organization said in a Dec. 10 news release.

“This rise coincides with the onset of winter in the northern hemisphere and an increase in acute respiratory infections caused by influenza and other respiratory viruses typically observed at this time of year.”