If flu activity in Australia and the Southern Hemisphere is any indication, Canada, and North America on the whole, could be in for a nasty flu season in the months ahead.
Australia, Hong Kong – and other spots in the Southern Hemisphere — have grappled with one of their worst flu seasons on record.
Health officials keep a watchful eye over the flu in the Southern Hemisphere, which affects residents during their winter (or our summer). Its patterns there that lay the groundwork for predicting which viruses may make the rounds by the time they make their way north.
“The key thing with influenza is that it’s predictably unpredictable but a few arrows are pointing in the direction that this may be a bit more on the rough side for influenza seasons,” Dr. Isaac Bogoch, a tropical infectious disease specialist at Toronto General Hospital and the University of Toronto, told Global News.
“There were more documented influenza cases in Australia compared to last year and the year before, more hospitalizations related to influenza and more deaths,” Bogoch said.
And then there’s the predominant strain: H3N2 – what health officials say may cause the biggest problems. It’s the same virus that wreaked havoc three years ago when the vaccine was a mismatch.
It’s typically known for affecting older patients, leading to serious complications and higher rates of hospitalizations.
This time around it got worse because it “drifted,” creating subtypes of H3N2, according to Jason Tetro, a Canadian microbiologist and bestselling author.
“It’s basically gone from one root of the virus, one clade split into five. As a result of that, the vaccine strain is losing its ability to match these five different ones. It’s very difficult once you start seeing these changes to develop a new vaccine,” Tetro said.
“We have to find out if any one of those subtypes is going to take over in North America and then once we’re done that we have to decide if the vaccine is a good match,” he said.
Which strains are circulating this year?
There are three types of influenza: A, B and C. Influenza A is the “big bad one we always worry about,” according to Dr. Gerald Evans, a Queen’s University professor and Kingston General Hospital chief of infectious diseases.
Influenza C, on the other hand, is “inconsequential,” Evans says.
Influenza B, for its part, is an important disease in that it hits kids more than adults. Each year, the flu vaccine contains protection against two strains of influenza A and one strain of influenza B.
This year, public health officials are bracing for three major strains based on H1N1 called A/Michigan/45/2015, H3N2 known as A/Singapore/INFIHM-16-0019/2016, and a B strain, B/Phuket/3073/2013. This presents a problem as this year’s vaccine is not an exact match for the H3N2 and the B.
However, researchers in Australia suggest there will be overlap between the circulating strains and the vaccine, meaning getting the shot could still help your chances at staying safe.
And even if the vaccine is a mismatch, those who get the flu shot typically end up with milder symptoms if they get the flu.
This year, the flu virus should make an appearance by November, and by January, an upswing of sickness should hit the country and linger for about four weeks before influenza dies down, Evans said.
There are typically two peaks — one in December as kids return home from school, germs in tow, and again in January and into February, as frigid temperatures set in.
How do experts make their guesses?
Each year, influenza strains mutate and re-emerge, infecting victims and triggering a new season.
Scientists look at the patterns and make their predictions based on which viruses made their rounds in the Southern Hemisphere and estimate what mutations could occur before the influenzas make their way over the equator.
They narrow their guesses to only a handful and those three strains are then included in the seasonal vaccine that’s given to the masses.
Evans says that three-quarters of the time, the medical community is right, and the flu vaccine concocted that year is the correct defence against that year’s influenza.
Who should be getting the flu shot?
As always, doctors are advising Canadians to get their flu shots to help protect themselves, and the people around them from catching influenza.
At this point, Evans says that vaccination rates nationally sit at a meagre 20 to 25 per cent while health-care workers report higher numbers at about 40 per cent.
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Evans says that if at least 75 per cent of the public were to be immunized, “herd immunity” would occur. That means that if most people were vaccinated, the odds of an unvaccinated person getting sick would be very low.
He cautions that while most of us feel healthy, the flu shot has benefits that extend beyond our own immune systems.
“I’m a doctor and I get my shot every year so the likelihood of me getting the flu is reduced, and that means I’m unlikely to transmit to my family, my friends and to my patients that I see,” he said.
“It’s one of those things where it’s good for you, but it’s also good for everybody around you, too.”
Kids as young as six months old can start getting the vaccine.
It’s also recommended for populations at risk of complications. These people who are more vulnerable include pregnant women, children under five years old, seniors and residents in long-term care or nursing homes.
Those with underlying health problems, such as chronic diseases (asthma, chronic bronchitis, cancer) should also make their way to a flu vaccination clinic.
Evans suggests that getting the vaccine earlier helps. It takes about two weeks for the vaccine to be most effective, and its effects are long-lasting.
For more on the flu season, take a look at the government’s Flu Watch.
To read about flu prevention tips, take a look at the Public Health Agency of Canada’s website.