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

Heavy turnout at advance poll in Chilliwack

Some voters waited as long as two hours

Around the BCHL: Youth trumps experience for Chilliwack and Salmon Arm

Around the BCHL is a look at goings-on in the BCHL and the junior A world.

Retirement of Chuck Stam brought out kind words and fond goodbyes

Tuesday was the last council meeting for a councillor who has served Chilliwack for almost 20 years

Chilliwack City Watch member helps RCMP catch drunk driver

Volunteer flagged down officer after watching vehicle driving erratically on Yale Road

Indigenous Bloom the only dispensary operating in Chilliwack with the dawn of legalization

Ashwell Drive storefront is on Kwaw-Kwaw-A-Pilt First Nation land operating under a new ‘cannabis law’

Mellow opening to B.C.’s only legal pot shop

About five people lined up early for the opening of the BC Cannabis Store in Kamloops.

Money Monitor: Should you switch to a fixed-rate mortgage?

BMO’s Omar Abouzaher outlines the pros and cons of both types of mortgages

Earth still moving in Old Fort, B.C., but not above homes: geologists

Transportation Ministry crews are ready to start work on the Old Fort road

Pedestrian hit and killed in Vancouver

Police said in a statement that the man was crossing mid-block near Ross Street on SE Marine Drive just after 6 a.m

Around the BCHL: Youth trumps experience for Chilliwack and Salmon Arm

Around the BCHL is a look at goings-on in the BCHL and the junior A world.

Support high for Metro Vancouver SkyTrain, light rail projects: poll

Nearly 90 per cent were in favour of a UBC SkyTrain extension

Proportional representation grows government, B.C. study finds

Spending, deficits higher in countries where voting system used

Black market will thrive until small pot growers and sellers included: advocates

Advocates say the black market will continue to thrive until small retail shops and craft growers are included in the regime.

Goodbye cable, hello Netflix: 1/3 of Canadians cut the cord

Just under half of households no longer have a landline phone

Most Read