Canada could face the ‘worst ever’ flu season as experts warn the evolving strain could be a mismatch for vaccines
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With flu cases now rising in Canada, medical experts are preparing for a tough influenza season linked to the global spread of an evolving H3N2 strain that could be a mismatch for this year’s vaccine.
New federal data released Friday It turns out that about two percent of tests nationwide last week came back positive for influenza. That’s still below the five per cent threshold for Canada to declare a seasonal flu pandemic, but a significant increase from a few weeks ago.
The ongoing flu season abroad has been marked by record case counts in the Southern Hemisphere, and an early start to the season in parts of Asia and the U.K. As Canada heads into winter, it could be a sign of things to come.
“This is the second year in a row that more influenza has been detected in the Southern Hemisphere than average,” said Dr. Jesse Papenberg, a pediatric infectious disease specialist at Montreal Children’s Hospital and McGill University Health Centre.
“In terms of the number of cases, last year was probably the worst influenza season in Canada in a decade, and it looks like that may be the case again this year in terms of severity of illness.”
Intense flu season in Australia, UK, parts of Asia
In Australia, physicians recently rang the alarm This is the second consecutive record high flu year, after more than 410,000 laboratory-confirmed cases nationwide.
At the end of October, UK health officials announced Its flu season arrived a month earlier than usual, and cases were three times higher than last year, amid expectations of a “longer and longer-lasting flu season”.
UK officials said the flu has also arrived early in parts of Asia, including Japan, which has already declared a flu epidemic and closed many schools in the country.
There is speculation that a mutant strain of H3N2 is behind that initial surge. This is a type of influenza A that is generally known to cause more serious infections, especially in older people. But what’s particularly troubling to some experts this year is that these latest mutations are widening the gap between this virus and our available flu shots.
Dr. Danuta Skowronski, epidemiology lead for influenza and emerging respiratory pathogens at the BC Center for Disease Control, is among the Canadian researchers looking closely at these mutations.
Although this H3N2 subtype hasn’t changed much over the years, she says it has recently begun to show more dramatic structural changes as it has spread into northern countries, which could mean it could be “mismatched” to our latest vaccine.
This season’s flu shot targets two influenza A strains — H1N1 and other subtypes of H3N2 — as well as an influenza B strain.
“The differences between the circulating H3N2 virus and the virus in the vaccine are really quite different, and it’s no one’s fault. It’s just the nature of influenza. It’s a very variable virus,” Skowronski said.
‘It is too early to determine’
Canadian public health officials, meanwhile, are not making any predictions yet.
In a statement to CBC News, the Public Health Agency of Canada said it continues to monitor respiratory virus activity globally to detect emerging trends affecting Canada.
However, the agency stressed that published research Turns out that due to different seasonal dynamics, data from the Southern Hemisphere is not a “direct predictor” of what might happen here.
“At this time, it is too early to determine what type of flu season Canada will experience; it will depend on things such as dominant influenza subtypes, co-circulation of other respiratory viruses, vaccine effectiveness and vaccine coverage.”
As flu season approaches, the province is unveiling its rollout for COVID-19 and flu vaccines. Health officials are encouraging people across B.C. to roll up their sleeves and get vaccinated. As Michel Ghoussoub reports, they’re also warning of a rise in misinformation about the safety of the vaccines.
‘The worst kind of flu season’
Although there is still only preliminary data available on what types of influenza are circulating in Canada, the latest federal figures last week show a 50/50 split between H1N1 and H3N2 among influenza A subtypes found across the country — but all outside experts interviewed by CBC News expect H3N2 to continue to rise.
“We’re more likely to see a major pandemic caused by that mutated virus, and certainly, that’s what they’re seeing elsewhere in the UK and in Japan,” Skowronski said. “We may have a different profile, but I think it’s better to be prepared for the fact that it’s likely to come – and we’ve already picked up on that.”
He said that in many countries, school-going children are the first to be infected, but eventually the virus will reach adults, who are at higher risk of serious consequences. (The latest data shows that, by far, the highest number of flu cases in Canada are among seniors aged 65 and older.)
Dr. Alison McGirr, a researcher and infectious disease specialist at Mount Sinai Health System in Toronto, warned that the H3N2 season is typically “the worst kind of flu season.”
Papenberg said adults age 60 and older typically suffer the most damage. “So if this is H3N2 season, we can expect to see more hospitalizations and, unfortunately, more deaths.”
Flu and COVID-19 vaccine shot clinics are now operating in Newfoundland and Labrador. Last year, the province broke records — and not in a good way — with the highest number of confirmed cases and hospitalizations ever recorded. CBC’s Heather Gillis reports on change efforts this season.
Although this year’s shot may not be a perfect match for the new variant of H3N2 that may dominate in the coming months, all three medical experts stressed it is always worth taking, especially for Canadian seniors.
Seasonal vaccination clinics are already open in many provinces.
Health officials are asking Canadians to consider getting the flu shot along with other seasonal vaccines, including COVID-19 vaccines for those eligible — although some patients now have to pay out-of-pocket in some parts of the country, such as quebec And alberta– and respiratory syncytial virus shots, which can prevent serious illness In high-risk groups such as elderly adults and newborns.
