Cases of influenza are continuing to drop in Canada following an early and significant peak several weeks ago of the virus that swamped children’s hospitals across the country and led to the declaration of a flu epidemic.
Flu rates declined by 38 per cent in the first week of 2023, according to federal data published Friday.
This marks the second consecutive week in which influenza cases have “declined sharply” from a mid-November 2022 surge that saw the percentage of positive flu cases in Canada rise to 16 per cent — more than double the seasonal threshold of 5.0 per cent.
Flu rates are now below expected pre-pandemic levels, the Public Health Agency of Canada (PHAC) said in its latest FluWatch report.
“All surveillance indicators are decreasing and almost all indicators are within expected levels typical of this time of year.”
In the week of Jan. 1 to 7, a total of 1,749 laboratory detections of influenza were reported to PHAC. A majority of these cases — 77 per cent — were caused by a strain of the influenza A virus known as H3N2. The remaining 23 per cent were the influenza A strain known as H1N1.
Both of these strains are included in this year’s flu vaccine, which also includes two isolates of the influenza B virus.
The number of children requiring hospitalization from the flu has also significantly declined from a surge in childhood flu across Canada that peaked in late November.
The number of children admitted to hospital for the flu dropped by 38 per cent in the first week of January compared with the previous week. Only 30 influenza-associated hospitalizations were reported by the IMPACT network of 12 pediatric hospitals in Canada for the week ending on Jan. 7.
That represents a significant decline from the last week of November, when children’s hospitals across Canada were reporting record-high numbers of patients due to a surge in flu and respiratory syncytial virus (RSV) cases — a phenomenon that led to long emergency wait times for families.
Ottawa’s CHEO was so heavily affected by a surge in patients, the Canadian Red Cross provided volunteers to support hospital staff.
Hospitalizations of children for flu have dropped by 88 per cent since late November, according to the latest FluWatch data.
A higher proportion of seniors are now being infected with the flu, the figures show.
Almost half of all flu detections in early January were in Canadians aged 65 and over, up from 40 per cent the week before.
More seniors are also being hospitalized compared with children under five, which suggests influenza is returning to pre-pandemic seasonal patterns, according to the PHAC data.
Meanwhile, COVID-19 test positivity decreased slightly last week to 15.1 per cent countrywide compared with 15.6 per cent in the last week of December 222, while RSV is now following seasonal trends at the national level, according to PHAC’s latest weekly respiratory virus report.
“Compared to pre-pandemic seasons, RSV activity is (at) near average levels typical of this time of year,” the agency said in its report.