Last winter, parents and health-care workers across Canada sounded the alarm over an apparent increase in the number of children hospitalized with respiratory infections.

While parents said they were struggling to treat their children's symptoms amid shortages of over-the-counter cough and cold medicine, doctors warned that pediatric admissions for respiratory illness were pushing hospitals to their limits.

Now, a report from the Canadian Institute for Health Information (CIHI) bears out those stories with new data that shows hospitals did, in fact, see a significant increase in the number of stays due to respiratory illnesses among pediatric patients during the 2022-23 fiscal year.

In fact, CIHI's data shows hospitalizations for seasonal flu among children four and under spiked by 7,306 per cent, increasing to 2,444 cases in 2022-23 from only 33 cases the previous year. The federal fiscal year in Canada begins on April 1 and ends on March 31 the following year.

"Last year was unprecedented for all pediatric hospitals in this country and highlighted key gaps in our system," Dr. Lindy Samson, chief of staff and chief medical officer at the Children's Hospital of Eastern Ontario (CHEO), stated in a media release.

"We know from experience that viral seasons will continue to affect our young patients, and this is why it is so important that we invest in our pediatric health system and adopt public health measures to help reduce the risks."

Some health-care professionals attributed the spike in respiratory infections last year to the fact that physical distancing and public health restrictions during the pandemic kept most children from being infected with viruses like RSV and influenza for two years. Once those restrictions eased, the viruses began to circulate again, and some children whose bodies were inexperienced fighting them became very sick.

At the same time, health-care systems across the country were still reeling from the intense demands of the early pandemic, and hospital resources were already stretched going into the 2022-23 fiscal year.

The 10 most common respiratory illnesses among children four and under last year accounted for 32 per cent of all hospitalizations within that age group, up from 20 per cent the previous year. Among those illnesses, lower respiratory infections such as acute bronchiolitis were the top cause of hospitalizations, followed by pneumonia, asthma, COVID-19, acute upper respiratory infections and seasonal influenza.

Hospitalizations for pneumonia nearly tripled for Canadians 17 and under — rising to 9,871 from 3,447 the previous year — and almost doubled for asthma. Moreover, hospital stays for lower respiratory infections such as acute bronchitis increased to 19,909 from 9,501 among children four and under, and stays for COVID-19 rose by 43 per cent. Hospitalizations for acute upper respiratory infections also increased year-over-year by about a third, going up to 2,797 from 2,114.

"This increase in hospitalizations for respiratory illnesses among Canada's youngest patients presented additional challenges for hospitals," Juliana Wu, director of acute and ambulatory care information services at CIHI, said in a media release.

"We will continue to monitor and report on these trends to equip health system planners and decision-makers with the data required to continue to meet the needs of Canada's pediatric population."