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

Tseshaht First Nation athlete honoured with provincial sports award

Rain Thomas competes in three different sports

Alberni Valley firefighters pass the boot for Muscular Dystrophy

Annual fundraiser started in 1967 with Port Alberni Fire Department

Cougars spotted in Sproat Lake neighbourhoods

ACRD director warns residents to keep children, pets close

Who are the Frozen Franklins? Find out at the Alberni Valley Museum

The museum and Echoes in the Ice exhibit are open April 20 during Easter weekend

Former teacher returns to Port Alberni to lead Alzheimer’s Walk

Jory Mitchell celebrates his journey with late wife and her Alzheimer’s diagnosis

Sri Lanka invokes war-time military powers after nearly 300 killed in Easter bombings

Sri Lanka’s minister of tourism says 39 foreign tourists were killed in the Easter Sunday attacks

Bodies of 3 mountain climbers recovered after last week’s Banff avalanche

The men disappeared while attempting to climb the east face of Howse Peak in the Icefields Parkway

Happy birthday: Queen Elizabeth II turns 93 on Easter Sunday

Sunday is the first of two birthday celebrations each year for the queen

RCMP confirm witnesses say body found at Kelowna’s Gyro Beach

Police tape is blocking part of the beach and several RCMP officers are on scene.

B.C. fire department rescues kittens

Enderby homeowner not aware kittens in wood pile near garbage pile fire that got out of hand

QUIZ: How much do you know about Easter?

Take this short quiz and put your knowledge to the test

B.C. VIEWS: NDP’s lawyer show is turning into a horror movie

Court actions pile up over pipelines, car insurance, care aides

Global Affairs warns Canadians in Sri Lanka there could be more attacks

A series of bomb blasts killed at least 207 people and injured hundreds more

Most Read