Influenza Vaccines: What We Know About This Year’s Vaccines and ‘Virulent’ Dominant Strains

With flu activity well above typical levels in Canada, infectious disease experts warned against flu vaccinations, especially since this year’s dominant strain could cause more severe illness. I am concerned that I am taking too little.

Influenza vaccination is particularly beneficial this season because this year’s vaccine contains protection against the strains of influenza that have proven to be the most prevalent, which is not always the case. They say it’s possible.

As of Friday, the rate of positive flu cases had risen to 16% from 6.3% the previous week, Canada’s chief medical health officer Dr Teresa Tam said at a briefing last week.

That’s more than three times the seasonal threshold of 5% that prompted Public Health Agency of Canada (PHAC) to declare the beginning of a nationwide flu “epidemic” last week.

So far, the majority of influenza cases detected and laboratory-tested this year have been caused by a strain of influenza A virus known as H3N2. According to his FluWatch data, which PHAC releases weekly, the influenza A strain, known as H1N1, made up a very small proportion (only 3% to date).

Both of these strains are included in this year’s flu vaccine, which also includes two isolates of influenza B virus.

An international panel of experts convened by the World Health Organization before each flu season has determined, based on evidence from global surveillance, which types of influenza viruses are expected to cause the most illness and, therefore, seasonality. Provides advice on what should be included in flu vaccines.

Having the most prevalent strains circulating this year in this year’s flu vaccine is both good news and bad news for Canadians this flu season, says Michael G. DeGroot of McMaster University. said Matthew Miller, Institute Director.

“The good news is that the vaccine is a good fit. The bad news is that H3N2 strains tend to cause more severe infections than H1N1 strains,” Miller said.

Many Canadian doctors and infectious disease experts are preparing for a difficult flu season after observing Australia’s experience with the virus earlier this year.

Australia’s flu season is often used by experts to predict what will happen in Canada. This year, the country saw a significant rise in flu cases earlier than in previous years after two years of almost no flu cases amid COVID-19 safety measures.

This resulted in Australia’s worst flu season in five years. The situation was exacerbated by her H3N2 strain, known as the more “high-risk” strain, as the H3N2 strain is more likely to send vulnerable patients to hospitals. Sinai Health and the University Health Network of Toronto.

That’s why Sinha is calling on all Canadians to get their flu shot this year. This is to protect not only yourself, but those most likely to experience complications and death.

“Given that influenza remains the second leading cause of vaccine-preventable deaths in Canada and kills thousands of older adults each year, vaccination levels should be kept to levels set by Public Health. We have a good reason for trying to raise , we set a goal over the last ten years of at least 80%,” said Sinha.

“But we never got there.

Health Canada says it will not be able to estimate the effectiveness of the 2022-23 flu vaccination or the number of Canadians vaccinated until February or March.

But officials noted that last year, only 39% of all adults in Canada received a flu shot. This is similar to 2020, when influenza vaccination coverage among Canadian adults was only 40%.

As an anecdote, some doctors and experts who study vaccine trends say they are noticing low flu vaccine uptake so far this year.

“Yes, this is very worrying,” said Miller.

“It’s natural that the general public is fed up with vaccines, but we need to remember that vulnerable people need to be protected, even if we personally aren’t at risk.”

Children and adolescents are particularly affected by the flu this year, Miller said, pointing to a reality reflected in the FluWatch data collected by PHAC.

Among influenza detections for which age information was available last week, PHAC data show that 56% of cases were in individuals aged 0-19 years.

Donald Bing, M.D., an infectious disease expert and medical microbiologist at McGill University Health Center in Montreal, said testing for influenza is primarily done in hospitals, so laboratory-confirmed influenza among children and adolescents He said it was surprising to see so many cases of at the time of admission. Every year, older people are more likely to be hospitalized with influenza.

“Some of it could reflect a virus, but more importantly, it could also reflect human behavior,” Binh said.

The lifting of COVID public health measures, such as masks and physical distancing in places such as schools and day care centers, has been voluntary, particularly among young people, who feel they are generally healthy and often ‘immune to disease’. may have played a role, as they are less likely to follow “strong recommendations” to Made of masking, Vin said.

“It’s also possible that adults, especially older adults, who are usually at risk of severe flu, are being wary of COVID and simply continuing protective measures,” he said.

Given that the flu broke out earlier than usual this year, and cases of respiratory syncytial virus (RSV) and COVID-19 were also circulating, infecting large numbers of children, all Canadians Demands to get the flu vaccine have never been stronger. Vin said.

“I’m worried about this flu season, not just because of the flu, but because of[the mix]of these respiratory viruses,” he said.

“If there is a triple threat attacking our healthcare system, we need to get rid of all the guns so that the healthcare system doesn’t collapse. This includes things like keeping people safe.” I dated my COVID vaccine and got my flu shot.”

Sinha agreed, saying that while the majority of flu cases may now be among children and adolescents, the natural progression of these diseases could soon lead to cases among parents and grandparents. will connect.

And if a significant number of young people are sick enough to require hospitalization with influenza or RSV, this could also cause serious illness among the elderly.

“The best thing you can do to protect yourself from the flu is get the flu vaccine, and this year it’s especially good because the dominant strains circulating are particularly virulent strains.” Stated.

Sinha added that older Canadians will have access to enhanced flu vaccinations. This is what you should inquire about when trying to book a vaccine.