The hallways were packed. Staff were routing children to overflow spaces.
Each winter, the ancient negotiation between human vulnerability and viral persistence reasserts itself — but this year, Canada's children's hospitals are meeting that reckoning earlier and harder than most had prepared for. An aggressive H3N2 influenza strain has driven pediatric emergency departments in Ottawa and Montreal to their limits, with hospitalizations doubling and patient volumes reaching levels that even seasoned medical staff describe as unprecedented. The surge, concentrated now in Ontario and Quebec, carries the quiet certainty of a wave still building — public health forecasters expect the worst to arrive in the weeks ahead, and the rest of the country is watching the horizon.
- Canada's pediatric hospitals are being hit by flu volumes eight times higher than last year, with emergency departments in Ottawa and Montreal pushed well beyond their designed capacity.
- Most of the children falling seriously ill had not been vaccinated, and a mutation in the dominant H3N2 strain has raised questions about how well this season's vaccine matches the circulating virus.
- Medical experts are urgently pushing back against vaccine hesitancy, stressing that even an imperfect match still meaningfully reduces the risk of severe illness and hospitalization.
- The surge is currently concentrated in Ontario and Quebec, but historical flu patterns and real-time surveillance data suggest other provinces should expect their own wave within weeks.
- With the national peak forecast for late December — just as families gather for the holidays — hospitals are bracing for conditions that could grow significantly worse before they improve.
On a Monday in late November, nearly 300 children passed through the emergency department at CHEO, Ottawa's children's hospital, in a single day — a twenty percent increase from the year before. Staff routed patients into overflow spaces. Hospital administrators called the surge unprecedented. Most of the sick children had not been vaccinated against influenza. Hospitalizations had doubled compared to the same period in 2024, and public health forecasters were already warning that the worst was still to come.
The strain was not confined to Ottawa. At Montreal Children's Hospital, the emergency department had been relatively quiet through mid-November before the volume shifted sharply. By late November, more than 200 patients were arriving daily. Dr. Harley Eisman described watching twelve to fifteen new patients register every hour during a single night shift — far beyond what the department was built to absorb. In Toronto, a similar pattern was unfolding, with children presenting with fevers, coughs, and gastrointestinal symptoms.
Nationwide surveillance data showed influenza A climbing steeply across pediatric hospital sites from British Columbia to Newfoundland. The driving strain, H3N2, carries new mutations that scientists flagged as a potential mismatch with this season's vaccine. But Dr. Srinivas Murthy of B.C. Children's Hospital cautioned against the conclusion that vaccination was therefore pointless. The shot still offered meaningful protection against severe illness — the outcome that matters most — and he worried that headlines about the mismatch were discouraging families from getting vaccinated at all.
B.C. had not yet seen a major surge, but Murthy expected that to change. Flu waves that take hold in one region reliably spread to others within weeks. Ontario and Quebec were already overwhelmed. Internationally, Scotland had seen flu cases jump forty-five percent in a single week, and British health officials were warning of a particularly severe season ahead. For Canadian hospitals outside the current hot zones, the question was no longer whether a surge was coming — only when.
The waiting room at CHEO, Ottawa's children's hospital, filled to breaking point on a Monday in late November. Nearly 300 young patients moved through the emergency department in a single day—a twenty percent jump from the same stretch the year before. The hallways were packed. Staff were routing children to overflow spaces. And this, hospital administrators warned, was only the beginning.
Canada's flu season arrived early and arrived hard, slamming pediatric hospitals across the country with patient volumes that caught even experienced medical teams off guard. At CHEO, the numbers told a stark story: eight times as many children tested positive for influenza in November 2025 compared to November 2024. Hospitalizations doubled. Most of the sick children had not received a seasonal flu vaccine. Karen Macauley, the hospital's vice-president of acute care services, described the surge as unprecedented. Public health forecasters were already predicting worse ahead, with the peak expected to arrive in December.
The strain rippled across provincial lines. At Montreal Children's Hospital, the emergency department had been relatively calm through mid-November. Then the volume shifted. By late November, the facility was seeing more than 200 patients daily. Dr. Harley Eisman, who leads the pediatric emergency medicine division there, worked a night shift and watched twelve to fifteen new patients register every hour—well above what the department was designed to handle. Most tested positive for influenza A. In Toronto, St. Joseph's Health Centre's Just for Kids Clinic reported a similar pattern: children arriving with runny noses, coughs, prolonged fevers, sometimes vomiting and diarrhea. Dr. Anne Wormsbecker, the clinic's chief of pediatrics, urged families to get vaccinated before the holidays.
Nationwide surveillance data captured the acceleration. Between mid-November and late November, positive influenza A tests at pediatric hospitals jumped eight percent. In the week of November 16, influenza A accounted for thirty-five percent of tests. By the week of November 23, that figure had climbed to forty-three percent. The Surveillance Program for the Rapid Identification and Tracking of Infectious Diseases in Kids, which monitors real-time trends across more than a dozen pediatric hospital sites from British Columbia to Newfoundland, showed influenza now appearing far more frequently than other respiratory illnesses in children and teens.
The culprit was H3N2, a subtype of influenza A that typically drives higher hospitalization rates. This year's version carried new mutations. Scientists had flagged a potential mismatch between the mutations and this season's vaccine formulation. The worry was real enough that it made headlines. But Dr. Srinivas Murthy, a pediatric intensive care physician and researcher at B.C. Children's Hospital, pushed back against the conclusion some people were drawing. Yes, the vaccine might not be a perfect match. No, that did not mean people should skip it. The shot still offered substantial protection against severe illness—the outcome that mattered most. "People hear that and think they shouldn't get vaccinated," Murthy said. "That's not the right message."
B.C. Children's Hospital had not yet seen a substantial surge, Murthy noted. But he expected that to change. Flu surges that appeared in one region typically spread to others within weeks. Ontario and Quebec were already overwhelmed. The rest of the country was watching and waiting. Across the Northern Hemisphere, health officials braced for similar patterns. In Scotland, flu cases had jumped forty-five percent in a single week. British health officials were warning that the season ahead would be particularly severe. The question was no longer whether Canadian hospitals outside the current hot zones would face their own surge, but when.
Notable Quotes
The vaccine, regardless, will help prevent severe disease, which is what we all end up caring about the most.— Dr. Srinivas Murthy, pediatric intensive care physician, B.C. Children's Hospital
We were seeing 12 to 15 new patients register an hour, which is certainly above our hourly capacity.— Dr. Harley Eisman, medical director of pediatric emergency medicine, Montreal Children's Hospital
The Hearth Conversation Another angle on the story
Why did this flu season hit so much harder than last year? Was it just bad luck with the timing?
It's partly timing—the season started early—but mostly it's the strain itself. H3N2 is the culprit, and it's a subtype that historically sends more kids to the hospital. This year's version also mutated in ways that made it trickier for the vaccine to match.
So the vaccine doesn't work?
That's the misunderstanding everyone's making. The vaccine still works. It won't prevent infection perfectly, but it prevents the kind of illness that lands you in a hospital bed. That's what matters.
Why weren't more kids vaccinated before this started?
That's the harder question. Most of the children flooding these emergency departments hadn't had the flu shot. Whether that's access, hesitation, or just timing—the hospitals didn't say. But it's the clearest pattern in the data.
Is this going to get worse?
Yes. The hospitals are already at capacity in Ontario and Quebec. Public health forecasters expect the peak in December. And when surges happen in one region, they spread. Other provinces are probably weeks away from seeing what Ottawa and Montreal are seeing now.
What does "overflow spaces" actually mean for a kid in the ER?
It means the hospital is using hallways, waiting areas, spaces not designed for patient care. It means staff are stretched thinner. It means the experience is chaotic for families and harder on the medical teams trying to help.
Should people be worried?
Concerned, yes. The vaccine still works. Getting it now, before December, is the single most useful thing a family can do. But the hospitals are telling us plainly: they're overwhelmed, and it's going to get worse before it gets better.