A man walks pass a sign for flu shots in Toronto. (Doug Ives/The Canadian Press)

Flu cases spike across Canada, signaling peak of epidemic: experts

The dominant influenza A strain is H3N2, which tends to infect seniors in greater numbers

The number of flu cases is continuing to rise across Canada, suggesting the peak of infections with one of the dominant circulating strains could come within a few weeks — or even sooner, say infectious diseases experts, who describe this influenza season as “unusual.”

“We really haven’t seen a season quite like this in a little while,” said Dr. Michelle Murti of Public Health Ontario, referring to the mix of two primary strains making people sick during this year’s epidemic.

The dominant influenza A strain is H3N2, a nasty virus that tends to infect the elderly in greater numbers, with concurrent circulation of a B strain, a type that typically causes less severe illness. Influenza B can also affect older people and is the strain that most often infects children.

READ MORE: Researchers claim the ‘man flu’ does exist

READ MORE: B.C. rolls out 2017 flu shots

“Normally in a season, we’ll see a peak of influenza A happening some time towards the end of December or through January,” Murti said Monday. “And as that is coming down toward the end of February, that’s when we start to see that peak of influenza B activity into the spring and later season.”

But this year’s B strain, known as B/Yamagata, began circulating in the fall, much earlier than is usually the case.

B.C., for example, is seeing an atypical 50-50 mix of H3N2 and B/Yamagata, although other regions in Canada may have different ratios of the two strains affecting their populations, Dr. Danuta Skowronski of the BC Centre for Disease Control said from Vancouver.

“The spike in influenza activity that we’re experiencing now is not unusual,” she said. “In fact, such a sharp increase in activity is a signature feature of influenza that distinguishes it from other respiratory viruses that have a more prolonged, grumbling activity through the winter period.”

Skowronski described graphs illustrating flu activity as looking like a church steeple — with a sudden rise, a peak and then a sharp decline.

“We are currently spiking, but whether we have passed the peak or are continuing to rise, it’s still too early to tell,” she said, adding that peaks may arrive at varying times across the country as regions and communities experience major upticks in cases at different points in the epidemic.

In its weekly FluWatch report, the Public Health Agency of Canada says there were 11,277 laboratory-confirmed cases of flu across the country as of Dec. 30 — about 70 per cent attributed to H3N2 — with more than 1,000 influenza-related hospitalizations and 34 deaths.

However, Murti said those figures are an underestimate of the actual number of cases, as most people don’t seek medical attention for flu and, therefore, aren’t tested. As well, not all provinces and territories keep track of hospitalizations due to influenza.

“Looking at our numbers over the last couple of weeks and knowing there’s a bit of a reporting delay, we’re certainly on the upswing right now in terms of increasing activity for flu,” she said of Ontario. “So probably in the next few weeks, we’re going to continue to see increased activity.”

Murti predicts the province’s peak — for H3N2 cases, at least — will likely come in the next few weeks.

“But you really don’t know the peak until you’re coming down the other side,” she said.

Sheryl Ubelacker, The Canadian Press

Just Posted

Saanich police are seeking suspect in sexual assault report

Incident happened early Saturday morning near Rudd Park

Saanich to hear update on regional sewage treatment plant

Likely subjects of presentation include fate of trees along Grange Road, costs

Canadian students are smart cookies

Canadian teachers also among highest paid in the developed world

Local fundraising initiative addresses tampon recall

Period Posse checking donations during 10-day campaign

Victoria Literacy Connection needs volunteers for new Reading Partner program

The program will be in five Greater Victoria elementary schools

Langford elementary school kids test their hand at entrepreneurship

Students sold their own products at a Young Entrepreneurs Fair Friday

POLL: Are you dreaming of a white Christmas?

The rain Vancouver Island is famous for is coming down in buckets,… Continue reading

Greater Victoria Crime Stoppers wanted list for the week of Dec. 11, 2018

Greater Victoria Crime Stoppers is seeking the public’s help in locating the… Continue reading

Microscopic parasite found in Prince Rupert water affecting thousands

More than 12,000 residents affected by the boil water advisory issued Dec. 14

Trudeau lashes out at Conservatives over migration “misinformation”

Warning against the “dangers of populism,” Trudeau says using immigration as a wedge political issue puts Canada’s future at risk.

B.C. hockey coach creates ‘gear library’ to remove cost barrier of sport

Todd Hickling gathered donations and used gear to remove the cost barrier for kids to play hockey.

Canada’s ambassador meets with second detainee in China

Global Affairs says John McCallum, Canada’s ambassador to China, met with Spavor Sunday

‘They’re coming:’ Flying cars may appear in urban skies by 2023

Air taxis will number 15,000 and become a global market worth $32 billion by 2035

B.C. VIEWS: Andrew Wilkinson on taxes, ICBC and union changes

Opposition leader sees unpredictable year ahead in 2019

Most Read