Canada is on track to face its first full flu season in several years, one that starts earlier than usual, even as the country’s health care system is already struggling with respiratory infections like COVID-19 and RSV .
It’s hard to know how the next few months will play out, including how much strain serious flu infections will put on overwhelmed hospitals and how this year’s roster of viruses will interact now that SARS-CoV-2 is firmly in the mix.
But what is clear is that there is already a sharp increase in recent infections, and a “wave” of cases is likely on the way, said Dr. Sameer Elsayed, an infectious disease physician and medical microbiologist in London. Ontario, and professor with Western University.
“We’re going to have a great flu season, I expect, this year.”
At the national level, flu activity has been “highly increasing” and has exceeded the seasonal threshold of five percent of samples returning positive in late October. If these trends continue, the federal government will declare the start of a flu epidemic in Canada in its next update, scheduled for November 14.
Ontario has already passed that benchmark, with about 10% of newly positive tests for the dominant strain of influenza A this year.
In Public Health Ontario’s latest update on November 4the province said the flu season has started “more than a month earlier than is typically seen in pre-pandemic seasons.”
This early start comes as the province’s pediatric hospitals are already overflowing with sick children with illnesses such as respiratory syncytial virus, or RSV, and while positive COVID-19 test results are rising again, more recently it has reached 17 percent.
“In the coming months, Ontario will likely face the triple threat of respiratory disease,” warned Dr. Rose Zacharias, president of the Ontario Medical Association, a physician advocacy group. during a press conference this Wednesday.
Alberta also began to experience an increase in influenza A cases at the end of Octoberalong with the circulation of other pathogens, and BC public health officials are also monitoring a steady increase in positive samples.
“Right now we’re seeing flu spikes and samples coming through long-term care facilities, children’s hospitals and adult hospitals,” said Dr. Linda Hoang, medical microbiologist, associate director and Head of the Bacteriology and Mycology Laboratory Program at the BC Center for Disease Control.
Tracks of the southern hemisphere
How Canada’s flu season progresses from here could mirror, to some extent, what countries in the southern hemisphere experienced earlier this year.
In Chile, where the 2022 flu season has come and gone, influenza A began circulating “months earlier” than during pre-pandemic flu seasons, according to a recent report published by the US Centers for Disease Control. (The United States is also experiencing an early start, with southern states experiencing the largest increases.)
Chilean officials reported more than 1,000 hospitalizations during the season. That’s higher than during the COVID pandemic, when public health restrictions and other factors kept the flu at bay for more than a year, but lower than during recent flu seasons before the pandemic. The country’s flu shots also nearly halved the risk of hospitalization.
Data on laboratory-confirmed influenza cases in Australia this year They also show that the country experienced an early start and end to its flu season and a much higher level of infections than in any of the previous five years.
But the Australian government considered the clinical severity of the 2022 flu season, in terms of the total number of deaths and the proportion of patients admitted to intensive care, to be “low”.
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The Ontario Medical Association is urging people to wear masks indoors and get vaccinated against the flu and COVID-19 as concerns grow that a surge in flu cases could overwhelm an already overwhelmed health care system sees an influx of RSV and COVID patients.
So what do these trends portend for Canada in the coming months?
Alyson Kelvin, a virologist and researcher at the University of Saskatchewan’s Infectious Diseases and Vaccines Organization, said it’s possible that our flu season could also “rise and fall” earlier.
But he stressed that the combination of influenza and other respiratory viruses, including the first time that COVID is circulating in the winter months without any public health restrictions, makes the stretch ahead particularly difficult to predict.
It is possible that the early start of the flu season in the southern hemisphere, which is now being echoed in countries further north, suggests that the virus is moving into circulation after other waves of infections.
“We could see a further spike in COVID-19 cases, perhaps in early January,” Kelvin said. “But it could also just be the reaction to not seeing the flu for the last couple of years; I really don’t know. And I’ll be watching the numbers to see a clearer pattern over the next couple of years.”
Is it mask time again?
Hospital teams worry that waves of different viral infections will put months of strain on Canada’s health care system, even if flu cases alone mean high levels of hospitalizations this season.
“It’s only November,” said Dr. Fahad Razak, an internist at St. Michael from Toronto, during an interview with CBC News Network.
“Typically, the season for respiratory viruses, including influenza and RSV, but of course also COVID-19, would be expected to peak in the coming months. So we haven’t seen, probably, until how far will this go.”
The coming months could be “very, very difficult,” he added, given the already long wait times to access care at many overburdened and understaffed hospitals across the country.
Given these concerns, a growing chorus of doctors now they ask for wear a mask again within indoor environments to mitigate the spread of viral infections.
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Dr. Fahad Razak, internist at St. Michael, says the triple threat posed by COVID-19, RSV and flu should be tackled with public health measures such as mask mandates.
“If it’s added to the other layers of protection, including vaccination, then it could make a difference in terms of cushioning the increase so that hospitals can cope a little bit better,” said Public Health Canada’s director , Dr. Theresa Tam. he said at a press conference on Thursday.
A study published this week in the New England Journal of Medicine offered further evidence suggesting that masks can help mitigate the transmission of the virus. The peer-reviewed research, which focused on Boston school districts, found that lifting mask requirements was associated with roughly 45 more cases of COVID per 1,000 students and staff in the months after it ended of a state policy.
Masks are a blunt and imperfect tool, Razak said, but one that also helped keep the flu at bay in Canada for much of the pandemic.
The 2020 flu season it ended abruptly after a series of public health restrictions were put in place to combat COVID, and there was also no evidence of community circulation of influenza the following season.
The flu is usually thought to kill thousands of Canadians each year, while COVID is currently killing hundreds every week.
Canadians were encouraged to get vaccinated against influenza and COVID
Getting a vaccine to protect against both is paramount this fall, several medical experts stressed in recent interviews with CBC News.
It is even safe to get both a Booster blow from COVID and an annual flu shot during the same appointment, according to the National Advisory Committee on Immunization of Canada.
Kelvin, who has been studying influenza for some time, said Canadians should always take the threat of influenza seriously.
The added fear now, he said, is that it will roar back as another respiratory virus, SARS-CoV-2, is now in the mix.
“This will increase the cases of serious diseases,” he said. “And that’s what I want to be careful about: that we’re doing as much as possible to reduce the transmission of the respiratory virus in the community.”