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

WATCH: Lacombe and Red Deer Chambers prepare members for cannabis legalization

Luncheon speaker educates businesses on marijuana policies

WATCH: STARS lottery returns for 25th year

$500,000 grand prize up for grabs in support of air ambulance

UPDATE: Highway 2 lanes were closed due to milk truck fire near Millet

A southbound truck hauling milk and cartons collided with a bridge

UPDATED: Red Deer will officially be the home of the Canadian Finals Rodeo

CFR has potential to bring in an economic impact of $20-30 million

UPDATED: Red Deer will officially be the home of the Canadian Finals Rodeo

CFR has potential to bring in an economic impact of $20-30 million

WATCH: Lacombe and Red Deer Chambers prepare members for cannabis legalization

Luncheon speaker educates businesses on marijuana policies

Suspected Toronto serial killer targeting gay community arrested

A 66-year-old man is charged with first-degree murder in disappearance of two Toronto men

Barenaked Ladies, Steven Page, to be inducted into Canadian Music Hall of Fame

Canadian band to get top honours at 2018 JUNO Awards

B.C. out of the running for Amazon’s next headquarters

Toronto is the only Canadian city left in the running despite the province backing Metro Vancouver’s bid for new Amazon headquarters

Post interest rate hike debt tips

What to do about your debt and mortgages after the interest rate hike

Foreign workers sleeping in Alberta Burger King basement

Alberta Health Services said its inspectors found foreign workers sleeping in the basement of the Lethbridge restaurant

Court application halts release of bread price-fixing documents

Bread price-fixing documents won’t be unsealed Thursday, Loblaw says

Pharrell and N.E.R.D to headline NBA All-Star halftime show

11-time Grammy winner Pharrell and his hip hop-rock band N.E.R.D. will headline the halftime show at the 2018 NBA All-Star game in Los Angeles

Heritage Minister wants zero tolerance for harassment in entertainment industry

Heritage Minister Melanie Joly had two meetings to discuss harassment in the film, TV and theatre worlds

Most Read