Influenza activity in Canada is declining following an unusual late-spring surge in the respiratory virus that has seen little spread during the COVID-19 pandemic.
Around this time of year, influenza cases in Canada usually are in steady decline following the fall and winter seasons, but a resurgence in early April when numerous COVID-19 measures lifted created an anomaly in that trend.
Flu cases have been low since the onset of COVID-19 in 2020, but with the pandemic easing in certain parts of the world, other respiratory viruses are beginning to reemerge and Canadians should be prepared, especially considering what’s happening in Australia.
“Their numbers of (flu) cases are higher than the five-year average for that sort of time of year. … So they’re seeing quite a few cases of influenza-like illness and confirmed influenza,” said Dr. Susy Hota, an infectious diseases specialist with the University Health Network in Toronto.
“It’s a precursor to what we could face.”
Australia’s flu season, which typically runs from May to October, has long been looked at by Canadian health experts in preparation for flu season here, which usually begins anywhere between late October and early January.
In Australia, influenza cases have been on the rise since early March, and have exploded in recent weeks.
Between May 9 and May 22, there were 26,193 laboratory-confirmed influenza cases in Australia, which is more than three times higher than the previous reporting period between April 25 and May 8, the government said in its latest report. The country has logged 38,743 cases so far this year.
In Queensland, the regional government has made flu shots free with cases doubling every week in the area.
“We would expect cases to peak in August during a normal flu season, however statewide flu notifications have been doubling each week and continue to rise sharply with 4,230 new cases in the past week,” said Queensland Health Minister Yvette D’Ath in a May 31 news release.
“The current data trend indicates we may surpass the peaks experienced in 2017 and 2019 flu seasons, but also that we may reach these numbers much earlier in this season.”
When Canada’s flu cases began to spike in the spring, COVID-19 measures designed to protect the community from the novel virus started to lift across the country as disease levels began to decline.
Those measures helped protect against other respiratory infections like influenza, which has been nearly non-existent in Canada since the onset of the pandemic, experts said.
So far this reporting season, which Ottawa indicates as starting on Aug. 29, Canada has logged 12,693 influenza cases as of May 28, it said in its June 3 report. On average, the country sees 46,539 cases recorded by this time of year.
When Global News reported on the spread of influenza at the beginning of May, Canada had logged 1,842 cases of influenza to date.
Ottawa recorded 69 influenza detections in the 2020-21 flu season. Normally, around 52,000 cases are detected each year.
Aside from the easement of COVID-19 restrictions, part of the reason Canadians saw an increase in influenza cases was due to an uptick in testing, said Dr. Gerald Evans, an infectious disease specialist at Queen’s University in Kingston, Ont.
A total of 16,031 tests for influenza were performed in Canada between May 22 and May 28, the government said in its June 3 report, which was above the weekly pre-pandemic average of 3,197 tests.
Australia is doing more influenza testing this season as well with COVID-19 circulating alongside other respiratory illnesses, Evans said.
“By the time spring rolls around, typically in any other given year, the number of influenza tests we do is actually a lot smaller than what we were doing before the influenza season hit and during the early period (of the season),” he told Global News.
“What was happening this year is we were still doing a lot of COVID testing but … a lot of that involved testing for influenza, so the result of which we were doing a lot more tests this spring, which allowed us to see these influenza cases as they appeared.”
With an expected COVID-19 resurgence in the fall, it’s important for Canadians to stay up-to-date with their vaccinations as well as practise protections like masking and good hygiene designed to stop the spread of the coronavirus, Hota and Evans said.
“This summer we’ll probably get through without it being too much of a problem with influenza and hopefully COVID, unless something really shifts in terms of different variants, but both of these things are still active and we have to be aware about what could happen when we hit the cooler seasons,” Hota said.
“If you’re using measures to prevent COVID-19, they’re probably going to be effective against influenza,” Evans said.
“If people can use those methods, even if they’re not mandated, that’s really going to help us keep those influenza numbers down.”