Flu cases surge across Canada, public health agency reports

Influenza continues to increase quickly across the country, according to the latest data released by Health Canada. (CTV Calgary)

Influenza continues to increase quickly across the country, according to the latest data released by Health Canada.

For the week ending Dec. 13, the health agency reported that flu activity was “high and increasing,” with 27.7 per cent of tests being positive. This marks the highest value of positive tests recorded in the last three seasons, passing the 27.6 per cent of positive tests reported in the week ending Feb. 15, 2025.

According to Dr. Isaac Bogoch, an infectious disease specialist at the Toronto General Hospital, this flu season appears more significant than previous ones.

Bogoch says this is because of the three viruses that are currently circulating: two are influenza A, H3N2 and H1N1, and one is influenza B. He says the H3N2 flu strain is the predominant one.

“Years that are H3N2 dominant tend to put more pressure on (the) health-care system,” Bogoch told CTVNews.ca in an interview Friday. “They tend to be more significant and tougher compared to an average flu year.”

According to the latest data, the percentage of positive tests for COVID-19 was stable in the recent reporting week, while the percentage of positive tests for RSV is slowly increasing, but is below expected levels.

However, the number of flu-related outbreaks is increasing, with 284 reported. Of those outbreaks, 65 per cent were associated with influenza.

The rate of respiratory viral hospitalizations reported by participating provinces and territories is also increasing: the number of hospitalizations for the week ending Dec. 13 is more than 2,700, compared to nearly 2,000 reported the week ending Dec. 6.

According to FluWatchers, a volunteer program that helps track the activity of common viruses in Canada, the percentage of FluWatchers reporting cough and fever is higher than any week of the past three seasons.

For Bogoch, he says the take home message is that it is not too late to get the flu vaccine.

“The risk factors for severe illness are the older and younger cohorts, pregnant women, and people with underlying health conditions ... but even if you don’t have risk factors, influenza can still cause a really nasty illness. People can get very sick from it,” he said.

“The vaccine is not perfect, we know it’s not perfect, but it can still reduce the risk of getting the infection and even if you do get the infection, it can still mitigate the severity for symptoms.”