January 19, 2015 11:28 am
Updated: January 19, 2015 11:29 am

Nasty H3N2 flu season may have peaked in Canada, health officials say

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WATCH: According to a new U.S. report, this year’s flu shot is only 23 per cent effective. Su-Ling Goh reports.

TORONTO – Canadians may have seen the worst of this year’s flu season — while H3N2 is still widespread across most of the country, the number of cases may have peaked at the start of the year.

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The flu is still spreading across British Columbia, Saskatchewan, Manitoba, Ontario, Quebec and Newfoundland. In Alberta, the same regions have reported widespread activity for a third week straight, according to the latest update from the Public Health Agency of Canada.

The beginning of 2015 saw the country’s highest number of outbreaks in long term care homes – 152, a record number over the past five years.

But the number of positive flu cases decreased between Jan. 4 and Jan. 10, “suggesting that the seasonal influenza has peaked,” the Flu Watch report says.

At the start of the year, there were 4,579 positive cases, down from the 5,313 recorded at the end of 2014.

READ MORE: 5 ways to protect yourself from the flu

Laboratory detections, prescriptions for antiviral drugs and hospitalizations have all calmed down after a nasty season that hit seniors hard and left emergency rooms swamped.

It’s been an ugly flu season for a couple of reasons: for starters, H3N2 is the predominant strain and it’s traditionally more potent. Doctors told Global News that it could lead to more hospitalizations.

“It’s possible this might be a flu season where we’ll see people get more ill, which causes people to require hospitalizations versus riding out the flu at home,” Dr. Gerald Evans, a Queen’s University medicine professor and chief of infectious diseases at Kingston General Hospital, said.

By early December, the Centers for Disease Control and Prevention warned that the flu vaccine on hand was a mismatch. Last week, it reported that the flu vaccine is only 23 per cent effective, which is among one of the worst results since they started tracking how well the vaccines work.

Ideally, the best flu vaccines are 50 to 60 per cent effective.

The northern hemisphere, more or less, uses the same vaccine – there are only miniscule variations by product and manufacturer, which means the vaccine was just as effective in Canada, too.

READ MORE: Nasty H3N2 flu season worsens as cases rise across Canada

The Public Health Agency of Canada has already conceded that the vaccine isn’t “optimally matched” to protect against H3N2. In an emailed statement, an agency spokesperson said the Canadian situation mirrors the U.S.

“To date, the available Canadian data estimates a low level of vaccine effectiveness against the H3N2 strain consistent with the U.S.,” the statement read.

Each year, strains of the influenzas mutate and re-emerge, infecting victims and triggering a new season. Those of us in the northern hemisphere keep a watchful eye over the flu in the southern hemisphere, which affects residents during their winter (or our summer).

READ MORE: Nasty flu season strikes as H3N2 cases spike across Canada

Picking out three strains for a vaccine is guesswork, and by the time influenza makes its way into the northern hemisphere, it’s had time to mutate or “drift.” But by then, the flu vaccine is already formulated.

This year, the vaccine isn’t as effective but health officials say it’s still worthwhile to roll up your sleeve and get the shot.

READ MORE: This year’s flu shot may not be the right match, CDC tells doctors

Overall, this year’s flu season – the way it started a little early and tapered off at the start of the New Year – is similar to last year’s season, the Flu Watch report suggests.

carmen.chai@globalnews.ca

© 2015 Shaw Media

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