New flu vaccination guidance boosts protection for our most vulnerable

Some things never change. Take, for instance, the continuation of our annual peak influenza season. But despite the popular misconception that it’s no more serious than the common cold, influenza (the flu) remains a significant health risk, particularly for Canadians aged 65 and older.

Fortunately, new guidance from Canada’s National Advisory Committee on Immunization (NACI) may help reduce that risk with a preferential recommendation that older adults should receive any of the currently approved and available enhanced influenza vaccines (EIVs) over standard-dose versions. Immunosenescence – the age-associated decline of the immune system – means older adults may have a reduced immune response to the antigens found in regular or standard-dose flu vaccines, leaving them less protected than they should be.

Seasonal influenza together with pneumonia remains one of Canada’s 10 leading causes of death. On average, more than 12,000 Canadians are hospitalized because of influenza each year, with about 3,500 deaths attributable to the virus annually – mostly among older adults.

People 65 years and older are more susceptible to getting influenza because they have weakened immune systems and are more likely to suffer serious health consequences if they do. In fact, this group accounted for 76 per cent of the reported influenza-associated deaths in Canada in the 2022-23 flu season.

Vaccination remains the best way to protect ourselves against influenza, so it is important that Canada’s policies and programs particularly encourage older adults to get vaccinated. Sadly, despite the Public Health Agency of Canada having set a target of getting at least 80 per cent of older adults vaccinated against the flu, we are not achieving this goal.

The recently released NACI recommendation, “Supplemental guidance on influenza vaccination in adults 65 years of age and older,” was developed in response to provincial and territorial public health programs seeking guidance on the best vaccines for older Canadians. NACI’s experts conducted a thorough, systematic review of the clinical evidence to determine whether any of the influenza vaccines available in Canada should be preferentially used. It also reviewed economic data to better inform decision-making by public health programs.

Vaccination remains the best way to protect ourselves against influenza.

NACI concluded that none of the three (adjuvanted, high-dose and recombinant) EIVs was more effective than the others and that all are equally safe. NACI also preferentially recommended EIVs over standard-dose vaccines for the prevention of seasonal flu in adults 65 years of age and older to better counter the impact of immunosenescence in the population.

This latest guidance brings Canada in line with other jurisdictions, such as the United States, United Kingdom and Australia. For example, in 2022, the U.S. Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) recommended that adults 65 years of age and older should preferentially receive an EIV over a standard-dose influenza vaccine, concluding that evidence from direct comparisons between EIVs did not indicate the superiority of one over the others.

The result of the recently released NACI review is good news for everyone. By having three approved EIVs from two different manufacturers, health-care providers and public health programs across Canada will not have to rely on a single vaccine or supplier. This may help reduce the possibility of supply disruptions and allow eligible Canadians to get an EIV when they want and need one.

With all approved EIVs deemed equally effective, provincial and territorial health agencies will be able to choose the best vaccines for their population, taking into account factors such as access, overall health-care budgets and vaccine affordability. This is an important consideration as some of the EIVs currently available in Canada can cost up to four times as much as others without necessarily providing significantly higher protection.

At a time when health budgets are under strain, choosing a less expensive but equally effective EIV will allow our provinces and territories to optimize the delivery of annual flu shots and preserve more of their budgets to strengthen vaccine uptake for these and other high-priority immunization programs. Indeed, health agencies can redirect some of the potential savings toward vaccination awareness and access initiatives to educate the public about the seriousness of influenza while encouraging and enabling more people to get vaccinated.

Alternatively, generated savings could also be used to establish more vaccination sites during respiratory virus season to make it even more convenient for older Canadians to get a flu shot and other respiratory vaccines they are eligible to receive.

Empowered by NACI’s latest recommendation on EIVs, we should put all efforts into achieving our 80 per cent goal of getting older Canadians better protected against the more serious and deadly consequences of influenza in a more cost-effective way.