Flu spread among children and teenagers at ‘sky-high’ levels as experts fear wave of infections will worsen
A surge of influenza among school-age children has been linked to the recent deaths of several Ontario children, prompting Canadian families to get vaccinated as medical experts prepare for a worsening wave of infections across all age groups.
Three children aged five to nine died from complications of influenza this month, health officials from Ottawa Public Health and the Eastern Ontario Health Unit said in a report. statement on monday,
Officials are not releasing further details about the children, including whether they were vaccinated against the flu or had any underlying health issues, but did note that all three lived in the Ottawa area.
“There are childhood deaths due to influenza every year in Canada, but it is unusual to have such a high number of deaths in such a short period of time,” Dr. Trevor Arnason, Ottawa’s medical officer of health, told CBC News.
Nationwide, the latest federal data shows that more than 20 percent of all influenza tests are now coming back positive, with the highest number found in people 19 and younger. (The same data shows that compared to last week, there have been fewer than five child deaths across the country so far this season.)
The spike is being driven by the spread of H3N2, which is typically associated with more severe flu seasons — including a recent subtype of H3N2 with mutations that don’t cause more severe disease but make the virus significantly different from the one targeted in this year’s flu shot. According to the World Health Organization,
Dr. Jesse Papenberg, a pediatrician and researcher at Montreal Children’s Hospital, said it has been a long time since Canada experienced a flu season dominated by H3N2.
“So that means there are a lot of children who have probably never been exposed to H3N2, and so there is a very high probability of that type of infection in the pediatric population at this time,” he said. “I think that’s part of what explains the really high positivity rates in children.”
It also turns into a serious numbers game, Papenberg cautions, because higher prevalence of flu among school-aged children could mean more instances of serious outcomes — many of which could be prevented by annual flu shots, even if they don’t exactly match this year’s dominant strain.
The latest available vaccine effectiveness estimates show the current shot is up to 75 percent effective in preventing hospital visits in children aged two to 17, and 30 to 40 percent effective in adults, WHO said.
“It’s not too late to get vaccinated,” Papenberg said.
Children’s hospitals remain busy
While many areas are seeing an increase in children suffering from the flu, the early and rapid increase in illness among children and teens is occurring rapidly in Ontario.
At CHEO, the Children’s Hospital of Eastern Ontario, located in Ottawa, more than 300 tests came back positive for influenza in the first 10 days of December, a staggering increase from only 11 tests that came back positive during the same period last year.
Over the past week, the hospital’s emergency room has seen between 220 and 280 patient visits per day, with more than a dozen admitted patients, hospital officials said.
The pediatric clinics at St. Michael’s Hospital and St. Joseph’s Health Center in Toronto are also busy, with more tests coming back positive than hospitals do this time of year, said Dr. Anne Wormsbaker, a pediatrician at Unity Health Toronto.
Children are coming in with a variety of symptoms, he said, including some patients with long-term illnesses, including fevers that last for several days.
Province-wide, the percentage of influenza A tests coming back positive is now about 26 per cent – higher than the past three seasons, and with increases across all age groups. Public Health Ontario data shows,
Children and teens are currently hardest hit: about 64 percent of flu tests among children aged five to 11 are now coming back positive, while more than half of flu tests among children aged 12 to 19 are coming back positive.
“This is very high. It means that the amount of influenza spread among school-age children is really tremendous at this time,” Papenberg said.
The handful of recent deaths in Ontario are a “tragedy,” he said, adding that in any given flu year, pediatric deaths during the season can range from one or two to more than 10.
Health officials are warning of a rise in influenza among youth populations. The BC Center for Disease Control is reporting more cases of influenza in children, which they say has led to an increase in emergency hospital visits. Our Dan Burritt is joined by Dr. Tom McLaughlin, a pediatrician at BC Women’s and Children’s Hospital.
‘The sooner you get vaccinated, the better’
Papenberg was part of a team that analyzed pediatric flu mortality across Canada. That study identified a total of 80 influenza-associated deaths in Canadian pediatric hospitals between 2004 and 2022.
their studies, Published last July in the Journal of PediatricsFound that more than half of those cases were in children under five years of age, while children with high-risk conditions accounted for about 80 percent of the cases.
The researchers found that only a quarter of hospitalized children with known vaccination status had received the latest flu shot.
Medical experts expect a similar situation this year too public health teams It’s being emphasized that it’s important to get vaccinated against influenza as families begin gathering for the holidays.
“The sooner you get vaccinated, the better, because we know that during the holiday season, there’s going to be a lot of intergenerational mixing,” Papenberg said. “What I see is that we could have a really bad influenza season for our most vulnerable population, which is our elderly.”
While flu often rises first among younger age groups, eventual outbreaks among older adults typically result in far more cases of severe illness. For example, in recent weeks, federal data shows a rising number of influenza outbreaks in long-term care homes.
“We can help reduce the severity of symptoms, especially in people who are at higher risk — so, the elderly and young children, people with chronic medical conditions,” said Dr. Sidd Thakor, a pediatrician at the Children’s Hospital of Calgary.
He said the facility is largely over capacity due to the influx of young flu patients, while the hospital is also bracing for a surge in respiratory syncytial virus (RSV).
“There is a lot of misinformation out there regarding vaccines,” Thakor said. “We’re seeing the outcome of this: We saw measles first, now we’ll see influenza and then we’ll see what happens with RSV.”
In recent years, many vaccine-preventable diseases, such as measlesDespite significant evidence showing the safety and success of vaccination programs in protecting people from severe disease, vaccination rates have declined sharply in countries such as Canada.
Wormsbaker in Toronto recommended getting a seasonal flu vaccine as well as other basic precautions — including washing hands, staying home when sick and not sharing food and drinks.
“Like in the summer, we apply sunscreen; it’s not perfect… but it gives us some protection, and the vaccine does the same thing,” she said.
