Flu season: When is the right time to get vaccinated?

The transition from summer to fall signals the start of a new school year, cooler weather, and unfortunately, the start of flu season.

Health Canada and the World Health Organization recommend getting a flu vaccination every year because influenza viruses evolve and vaccine effectiveness decreases over time, but since the COVID-19 pandemic, vaccines have also been developed to fight the infection, and new variants of the novel coronavirus have required updated vaccinations over the years.

Earlier this monthHealth Canada has ordered the disposal of remaining COVID-19 vaccines and the replacement with the new Moderna vaccine, which is Within this week.

And this week, Ontario and Quebec It was also announced that a newly approved respiratory syncytial virus (RSV) vaccine will be made available to newborns, young children, pregnant women, and people aged 65 and older, which is expected to reduce the number of infants and elderly people hospitalized.

With all these vaccinations, some Canadians may have questions about the effectiveness of each vaccine, whether they should get all of them, how often they should be given, whether it's safe to get them all at once or if they should be spaced out, etc. CTVNews.ca asked infectious disease experts what their suggestions are as flu season officially begins.

Hit the shot

Jeffrey Pernicka is an Associate Professor in the Department of Pediatrics at McMaster University, specializing in pediatric infectious diseases. His research involves the assessment, diagnosis and management of infectious diseases in sick and hospitalized children.

“A lot of these respiratory viruses tend to have stereotypical circulation patterns, many of which emerge in the winter,” Pernica said. “The problem with the flu vaccines that we have is that they don't provide long-term protection against these specific flu strains.”

He added that for those most at risk, particularly older Canadians, the protection from a single dose of the vaccine doesn't last very long, so they'll likely get COVID-19 vaccinations annually.

Pharmacist Kim Nguyen administers a dose of Moderna's SpikeVax COVID-19 vaccine at a CVS in Cypress, Texas, Wednesday, Sept. 20, 2023. (Melissa Phillip/Houston Chronicle via The Associated Press)

As for RSV, Pernicka said it likely won't be an annual vaccination, but the Canadian National Advisory Committee on Immunization recommends that everyone over the age of 75 get the vaccine, preferably in the fall before cases start to increase. RSV also hits babies and young children hard.

“RSV is the deadliest respiratory pathogen affecting children,” Pernica said, adding that one strategy health professionals have is to vaccinate pregnant women with an RSV vaccine late in pregnancy to mount an immune response in their babies to make antibodies, similar to how the whooping cough vaccine is sometimes used.

Multiple vaccines at once

Despite claims that giving multiple vaccines at once is dangerous or less effective, Pernica says that's not true and there are sometimes compelling reasons to get multiple doses on the same day.

“You often have a lot of people who need the flu vaccine in the fall, you have a lot of people who need the COVID-19 vaccine in the fall, and now you have even more people who need the RSV vaccine,” he said. “As a practical matter, it's often much better to give all of those at the same time.”

both Health Canada and National Center for Immunization and Respiratory DiseasesThe National Public Health Service, part of the Centers for Disease Control and Prevention (CDC), says it's perfectly fine to get all your vaccinations at once.

Vaccine hesitancy

Vaccine hesitancy has risen sharply in Canada since vaccines were introduced throughout the COVID-19 pandemic.

Because of this, doctors like Pernicka can sometimes have a hard time explaining to patients, or parents of younger patients, why regular vaccinations are important.

“Vaccine hesitancy is a real issue because vaccines are the cheapest and yet most effective medical intervention,” he said. “The basis for addressing this issue is to talk to people and listen to what they have to say.”

Pernica added that the key to people getting vaccinated is making sure they have all the information they need to make a decision, especially when it comes to the RSV vaccine.

“COVID-19 is devastating to older adults, but RSV is just that for children. I want to emphasize to every doctor, every family, every healthcare provider that RSV is not good when contracted in early infancy, and we now have a very effective treatment.”