Canada's flu test positivity at highest level since 2020 season: report

The flu may be at its worst in Canada since the COVID-19 pandemic.

The Public Health Agency of Canada's Flu Watch report, released Friday, shows test positivity for influenza at 26.9 per cent and rising.

"Nationally, indicators of influenza activity continue to increase," according to the report. "The percentage of tests positive for influenza is now at its highest value since the start of the 2020-21 season."

The agency's surveillance for influenza includes hospital-based data, weekly surveys of Canadians who are asked about new respiratory symptoms and people who test positive for flu when they seek medical care.

"Per cent positivity will be tracked over time to see when that peak happens and when the burdens are high," Dr. Zain Chagla, an infectious disease physician at St. Joseph's Healthcare and an associate professor at McMaster University in Hamilton, said on CBC's The Dose.

Of the respiratory illnesses that are tracked, such as COVID-19 and respiratory syncytial virus (RSV), flu activity was highest in regions of Ontario, British Columbia, Quebec and Alberta.

Influenza activity is more localized in regions of Yukon, Alberta, Saskatchewan, Ontario, Quebec, New Brunswick, Nova Scotia and Prince Edward Island.

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Canada’s flu season typically starts to wind down at this time of year, but doctors are instead seeing a surge in cases. Quebec alone saw 4,600 cases last week, with some ending up in the ICU.

Nationally, indicators of COVID-19 and RSV decreased.

By age group, most of the influenza detections and hospitalizations have been among those aged 65 and older.

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In terms of severity of illness, critical care numbers are comparable to previous years, Chagla said.

The respiratory virus season tended to peak at nine weeks from 2014-15 to 2019-20, the agency noted. Canada is currently eight weeks into this season.

Influenza spreads from person to person through coughs, sneezes or face-to-face contact.

Common symptoms include fever, chills, cough, sore throat, runny nose, muscle or body aches, headaches, fatigue or tiredness.

Influenza vanished during the public health measures of the COVID-19 pandemic.