For more than two years, as Canadians experienced a roller coaster of COVID-19 infections, influenza seemed to take a backseat.
The family of viruses that causes the flu was barely spreading across the country until a recent, belated return of Influenza A caught scientists’ attention.
In March — as COVID-19 restrictions lifted and more people began mingling — positive tests for influenza A viruses began rising in Canada. By late April, federal data showed a nearly seven per cent test positivity rate, close to the average level for this time of year and largely driven by a spike in Quebec.
This unusually late flu season may offer clues for how COVID and influenza will impact each other in the years ahead, with one theory suggesting these two rival viruses could ebb and flow — but it’s tough to predict what, exactly, that would look like.
“It’ll be interesting to see what happens as COVID gets less dominant, if influenza starts to compete with it, and they have a tug of war over the next couple of years,” said Dr. Sumon Chakrabarti, an infectious diseases specialist with Trillium Health Partners in Mississauga, Ont.
Flu typically spikes in winter
In a typical flu year, cases first rise in the fall, spike in the winter and taper off in the spring, with sporadic infections throughout the rest of the year — with influenza A viruses circulating before influenza B.
The viruses’ disappearance throughout the pandemic might be tied, in part, to shifts in behaviour throughout much of the last two years as COVID-19 surged unpredictably, variant after variant.
“We were able to successfully suppress influenza circulation with our other public measures related to COVID-19,” said Dr. Danuta Skowronski, the epidemiology lead for influenza and emerging respiratory pathogens at the BC Centre for Disease Control.
The lifting of restrictions, coupled with a rise in global and domestic travel, likely played a role in influenza returning in recent months, said Dr. Isaac Bogoch, an infectious diseases specialist at the University Health Network in Toronto.
A mismatched flu vaccine this season may be another factor behind this unusual spike, as U.S. public health authorities reported, or simply waning immunity from shots given back in the fall, according to Skowronski.
But some avid COVID-19 watchers say the virus that causes it, SARS-CoV-2, may also have helped keep influenza at bay.
A sign indicating the estimated wait time at Humber River Hospital is pictured in its emergency department in Toronto on April 26. The hospital is facing higher patient volumes, and a rise in flu cases. (Alex Lupul/CBC)
‘Viral interference’
There was once speculation that COVID-19 and flu could create what some dubbed a “twindemic,” with both types of infections hitting countries at once, but those fears haven’t materialized.
Instead, some medical experts say there could be some level of “viral interference,” in which a virus such as COVID-19 pushes out other pathogens at a population level for a period of time.
“There’s some type of interesting viral suppression and competition going on here,” said Chakrabarti, who suggested COVID and flu may ebb and flow in circulation.
Throughout the pandemic, he explained, widespread COVID-19 infections may have kept people’s immune systems on high alert, giving SARS-CoV-2 a long-term advantage over the flu.
Influenza A cases began rising in Canada unusually late this year, following the lifting of public health restrictions and when more Canadians began mingling and travelling. (Alex Lupul/CBC)
“There were flu outbreaks this year, mostly in pockets of the United States, but still it clearly wasn’t a regular flu season and influenza was clearly suppressed,” echoed Bogoch.
“Now, people talk about viral interference with influenza and COVID and I wouldn’t ignore anything. I think the short answer is you can’t get overconfident with how the next year or so is going to play out.”
On the flip side, virologist Alyson Kelvin of the University of Saskatchewan’s Vaccine and Infectious Disease Organization said the sudden return of influenza may actually be tied to millions of Canadians’ immunity being dulled by the fifth and sixth COVID-19 waves — not sharpened by a COVID-19 infection.
“The circulation of SARS-CoV-2 — specifically Omicron — may have left people slightly immunocompromised,” she said.
“After the virus comes in and infects people, their immune system is weaker, leaving an opportunity for Influenza A to infect people in the weeks following their initial Omicron infection.”
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Different pattern of influenza possible
Several experts who spoke to CBC News did agree there could be unexpected shifts in the influenza season based on how the virus behind COVID-19 operates going forward.
“Will SARS-CoV-2 and COVID-19 cases become more seasonal? If so, we might see a different pattern of influenza cases,” Kelvin said.
In the short term — more reassuringly — both viruses are expected to fade away as the weather warms up before returning, at some point, in the fall.
This lull period is the time when health-care systems and governments need to start planning for an uncertain future, according to Dr. Leon Rivlin, chief of emergency medicine at Humber River Hospital.
Dr. Leon Rivlin, chief of emergency medicine at Humber River Hospital, inside the emergency department in late April. He is bracing for an uptick in the number of COVID-19 cases. (Alex Lupul/CBC)
Right now, as flu cases are ticking up, hospitals are still facing staffing shortages tied to COVID-19, he said. On his team, seven physicians called in sick for suspected SARS-CoV-2 infections just last weekend.
“We’re going to have this upsurge again,” he warned. “And once again, we’re going to be strained for human resources.”
The months ahead could be crucial to ensure Canadians continue getting vaccinations that offer protection against severe illnesses, while policy makers ensure there’s adequate space and staff to handle patients who do fall seriously ill with COVID-19 or flu.
“There’s going to be both short-term and long-term solutions,” Chakrabarti said. “Ultimately, we need some type of way to absorb any sudden surge of infections that occurs.”
The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.
It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.
Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”
Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.
Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.
A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.
On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.
Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”
But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”
“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.
Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.
Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.
Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.
“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.
“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”
This report by The Canadian Press was first published Sept. 13, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.
The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.
Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.
“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”
The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.
A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.
Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.
“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.
Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.
The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.
“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.
This report by The Canadian Press was first published Sept. 11, 2024.
ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.
Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.
Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.
The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.
“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.
Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.
Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.
Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.
A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.
This report by The Canadian Press was first published Sept. 10, 2024.
