Flu Hospitalizations Surge Across Canada as H3N2 Strain Spreads

Flu hospitalizations in Canada have surged dramatically, with rates nearly doubling in just one week. According to recent figures from Health Canada, the week ending December 13, 2023, saw 11,646 new cases of influenza, marking a nearly 30 percent increase in infections. This rise corresponds to a positivity rate of 27.7 percent across all tests conducted, up from 20.2 percent just a week prior, when there were 6,799 new cases.

The situation is becoming increasingly severe, as hospitalizations rose to 6.2 per 100,000 people, a significant increase from the previous week’s rate of 3.6 per 100,000. The number of reported outbreaks has also escalated, climbing from 91 in early December to 186 by mid-month. This surge in activity has affected 44 regions across 11 provinces and territories.

Widespread Activity and Vulnerable Populations

The spread of influenza is not uniform; Health Canada reports that “all indicators of influenza activity are high and increasing.” The agency noted widespread flu activity affecting regions in British Columbia, Alberta, Saskatchewan, Ontario, and Quebec. The populations hardest hit include both the very young and the elderly, with the highest hospitalization rates seen in adults aged 65 and older, as well as children under four years old.

Data indicates that 44 percent of new cases are among individuals aged 19 years or younger. The dominant strain circulating in Canada and the United States is the A(H3N2) influenza strain. Notably, a subvariant known as A(H3N2) subclade K has also been identified by the World Health Organization.

In Ottawa, the impact has been tragic, with three children aged five to nine reported to have died from complications related to influenza A. Local health officials are urging vaccination for all individuals over six months of age. In November, the Children’s Hospital of Eastern Ontario reported a significant increase in positive influenza tests among children, with numbers eight times higher than the same month last year. Hospitalizations for pediatric patients have also doubled.

Emergency Room Strain and Public Health Response

In Alberta, emergency departments are facing an overwhelming influx of influenza patients, with cases in the province rising by 70 percent in a single week. The hospital situation is becoming critical, prompting health officials to reinforce the importance of vaccination and preventive measures.

Experts highlight the significant risks posed by influenza, especially for young children. As noted by CHEO, “The flu is more than a bad cold.” Children under five are particularly susceptible to severe illness due to their still-developing immune systems and smaller airways, making early intervention crucial. The rapid spread of the virus in schools and child-care settings further complicates the situation.

As flu season progresses, health authorities continue to monitor the situation closely. Community engagement and vaccination efforts will be essential in mitigating the ongoing threat posed by this virus.