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Influenza cases in Canada see rare spring surge amid eased COVID-19 restrictions


The easing of public health restrictions that were aimed at curbing the spread of COVID-19 has lead to a surge in cases of another virus, experts say.

Since the start of April, Canada has seen a sharp increase in cases of influenza, something not typically seen in the spring. According to the Public Health Agency of Canada's (PHAC) most recent FluWatch report, there were 1,580 laboratory-confirmed cases of the flu between May 22 and May 28.

This is down from the peak of 2,121 flu cases seen during the week of May 8 to 14, but PHAC warns that the number of flu cases "remains above the epidemic threshold."

Last year, the period between May 23 and June 19 saw just one laboratory-confirmed flu case. Prior to the pandemic, a five-week period in May and June 2019 saw 864 laboratory-confirmed cases, an average of 172.8 cases per week.

Toronto-based emergency room physician Dr. Lisa Salamon says she's also noticed more patients with the flu in her practice, particularly children.

"I'm really seeing influenza a lot in children. A lot of kids are coming through the emergency department with various upper respiratory tract infections, fevers and lasting quite a few days," she told CTV's Your Morning on Tuesday.

Influenza-like illnesses made up 1.6 per cent of hospital visits in the latest report. This flu season has seen a total of 438 influenza-associated hospitalizations, with 225 of these being children 16 years of age and younger. PHAC says influenza-associated hospitalizations among children "remains above levels typical of this time of year."

Salamon says much of this trend can be attributed to the lifting of provincial mask mandates at schools and other indoor places that took place between February and May.

"We never have that much influenza at this time of year, but I really think that it's lifting of mask mandates," she said. "The fact that it's circulating here now, isn't that surprising. And also people are just congregating more"

Researchers have found that pandemic measures, put in place with the aim of slowing the spread of COVID-19, have helped stem cases of influenza. Last winter, normally the height of the flu season, the number of weekly laboratory-confirmed influenza cases peaked at 44, according to PHAC

Chief Medical Officer of Health Dr. Theresa Tam also cited the lifting of public health restrictions as the driving force of increasing flu cases, but said PHAC remains "cautiously optimistic that the warmer weather months will give us some reprieve from high transmission rates."

"When most population public health measures like closures and capacity limits were removed, we saw COVID-19 transmission rates rebound and now we're seeing influenza activity increasing up to the seasonal threshold, despite the opposite trend being expected at this time of year," she told reporters during last month's COVID-19 briefing.

According to PHAC's annual telephone survey on flu vaccine coverage in Canada, the vaccination rate among adults aged 18 to 74 is 30 per cent for the 2021-2022 flu season and 71 per cent among seniors 65 and older. Salamon said waning immunity from the flu vaccine may be another factor driving up cases.

"For those of us who got the flu shot back in the fall, it only lasts so long," she said.

Even though it may not be mandatory to do so, Tam said Canadians should continue to exercise "personal protective habits" such as masking in high risk settings in order to curb the spread of both COVID-19 and the flu.

"Masks continue to be an important layer of protection for ourselves while also helping to protect our loved ones," she said.

Salamon said this also underscores the need to stay home if you're feeling sick, something that fewer people are doing now that COVID-19 restrictions are loosening.

"We did a really good job at staying home if we're sick for two years. And now people are forgetting those simple principles," she said. "We always see people getting colds throughout the year. We just have to remember that if we have symptoms, regardless if it's COVID-19 or not, we should stay home." Top Stories

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