Flu is rearing its head again in Canada, with case numbers beginning to rise on the heels of another severe flu season in the southern hemisphere.
Scientists especially watching the spread of a new form of the H3N2 strain that may not match this year's vaccine.
This notorious form of influenza A is associated with more serious illness and recent mutations that may make the current flu shot less effective against it. CBC News recently reported.
So is there still any point in getting a flu shot this year? Medical experts say: absolutely. The latter vaccination provides sufficient protection against severe disease and is especially important for high-risk groups. Here's why.
Do flu shots really work?
The effectiveness of the flu vaccine may vary each season because the virus itself constantly changing.
There is also a big difference between how well flu shots protect against simple infection and the level of protection against serious illness and death.
“I think most people don't really worry too much about a runny nose or a cough. What they really want to make sure is that they don't end up in the hospital,” Matthew Miller, an immunologist and researcher at McMaster University in Hamilton, Ont., told CBC News.
In October Miller latest published study — an extensive review of hundreds of previous studies of infections in adults and children after flu shots — found that these vaccines do indeed work in important ways.
“We found that there was a really significant reduction in disease severity, and that's really encouraging because it gives a high degree of confidence that there is still a lot of value in getting the vaccine,” Miller said.
Vaccination can also limit transmission of the virus, helping stop the spread of influenza among vulnerable groups such as older people, who are at higher risk of death, Vancouver infectious disease specialist Dr. Brian Conway noted in the paper. recent appearance on CBC Hanomansing tonight.
With flu cases rising in Canada, medical experts are bracing for a difficult flu season due to the global spread of an evolving H3N2 strain that may not match this year's vaccine.
About nine out of 10 Canadians who died from flu and pneumonia in 2022 were aged 65 or older. Data from Statistics Canada showswith more than half of these deaths occurring in people aged 85 and older.
The result? “You should run, not walk, and get your flu shot now,” Conway said.
Who should get the vaccine?
Canada's National Advisory Committee on Immunization (NACI), composed of representatives best vaccine consultantssays flu shots are especially important for people at higher risk, such as older adults, young children, pregnant women and people with chronic health conditions.
“Influenza is a systemic disease,” Conway said. “You have a fever, muscle aches, have difficulty getting out of bed at times, may experience shortness of breath. This can affect the lungs, can lead to hospitalization, pneumonia, admission to the intensive care unit.”
Healthy young people are also affected more often than you might think.
More than one in 10 of all U.S. patients hospitalized with influenza last season did not have any underlying medical conditions, “underscoring that healthy individuals may also experience influenza-related hospitalizations or complications,” the CDC report noted. released in September.
In other words, everyone is at risk of contracting the flu.
NACI officially recommends that influenza vaccinations are “offered annually to all persons six months of age and older who do not have a contraindication to vaccination.”
For infants, NACI emphasizes the need for vaccination during pregnancy to help pass on antibodies and protect newborns in the first months of life—when they are “at high risk for complications from influenza infection and are too young to be immunized.”
What happens if you miss your flu shot?
Evidence shows that not getting a flu shot also puts people at risk of serious illness.
Two-thirds of US patients hospitalized in recent flu season were not vaccinated against influenza, CDC data shows, while a staggering 90 percent of children who die from the virus were also not fully vaccinated. (Guidelines stipulate that children under nine years of age who have never received a flu vaccine before should receive two doses. After that, the vaccine will be given as one annual shot.)
“The sad reality is that those people who end up in the hospital or the ICU or die every year … they largely didn't know they were at risk until it was too late,” said Miller, an immunologist at McMaster. “…This is something that can be prevented [with a flu shot.]»
Canadian data for the latest flu season, published in January in Eurosurveillance magazineshowed that the risk of getting flu severe enough to require a doctor's visit was cut in half for people who were vaccinated compared with unvaccinated people.
Should you still get an “incompatible” vaccine?
While vaccine researchers are always trying to stay one step ahead of the flu, it's difficult to predict exactly how this will happen. fast changing virus will develop from year to year.
This season is no different. As usual, this year's annual flu shot aims to cover multiple bases and includes components targeting different subtypes of influenza A, including the H1N1 and H3N2 strains, and influenza B.
Good news: A recent CDC study identified the newest vaccine formula. cut the number of hospitalizations for influenza by about half in countries in the southern hemisphere that have already passed the flu season.
But since then the situation has changed.
Alberta is reporting its first flu death of the season, and as CBC's Joe Horwood reports, experts are warning the evolving strain may not match the vaccine.
Dr. Danuta Skowronski, chief of influenza and emerging respiratory pathogen epidemiology at the British Columbia Center for Disease Control, recently told CBC News that the season in the southern hemisphere has been largely dominated by the H1N1 variant, while H3N2 has recently seen an increase in various countries.
The latest H3N2 strain is also acquiring mutations that widen the gap between what is circulating and what is contained in the current vaccine.
So, is this particular photo worth taking?
While the “inadequate” vaccine may be less effective against H3N2 in Canada this season, “the vaccine does not protect against just one type of flu,” Skowronski said.
“However, H3N2 will likely play a more important role in the coming season than in the last few seasons,” she added.
Miller stressed that the possibility of rising H3N2 cases makes flu vaccination even more important to help keep patients out of Canada's fragile hospital system.
“While it may not be the best option, its ability to prevent severe infection further underscores the importance of vaccination,” Miller said.
