COVID-19 2024 fall guide: Everything Canadians should know about new Moderna vaccine, current variants and more

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An updated COVID-19 vaccine is coming to Canada just in time for fall. On Tuesday, Health Canada announced it had approved Moderna’s latest COVID vaccine that’s been reformulated to target prevalent variants like KP.2. The updated formula will be available to Canadians as part of the fall and winter immunization campaigns.

In an email to CTV News, Public Health Agency of Canada spokesperson Anna Maddison said the new vaccines are expected to arrive "within days."

"Health Canada anticipates issuing a decision regarding the Novavax and Pfizer COVID-19 vaccines over the next weeks," Maddison said.

Are COVID cases on the rise in Canada?

The latest vaccine approval comes as Health Canada reports “most COVID-19 indicators are stable at elevated levels compared to spring.” Although trends vary across provinces and territories, outbreaks have been “slowly increasing” since spring. As of Sept. 17, COVID activity levels were reported as “high” for Ontario and Quebec.

What COVID strains are expected to dominate this fall?

Currently, the KP.3 and KP.3.1.1 FLiRT variants, derivatives of KP.1 and KP.2, are the most prevalent in Canada and the United States. As of Sept. 8, 67.5 per cent of COVID cases in Canada were from the KP.3.1.1 subvariant.

Experts believe new variants related to KP.3 will continue to emerge, however there are other variants, like XEC, spreading in countries like Germany, the United Kingdom and Denmark. Unlike KP.3, XEC emerged from earlier Omicron variants. In an interview with Yahoo Life, University of California, San Diego virologist Dr. Davey Smith said XEC is primed to become the latest subvariant to take over and "likely the one that will cause our winter wave" of COVID.

How is the new vaccine formula different from the old one?

Until now, Canada has only had access to vaccine formulas that were approved in fall 2023 and target the Omicron XBB.1.5. Moderna's latest formulation of their mRNA vaccine, Spikevax, targets the KP.2 variant.

Will the new vaccine formulation protect me from emerging COVID strains?

Many Canadians may be wondering if the new vaccine, which was formulated to protect against KP.2, will protect them against emerging variants, like KP.3 and the subvariant KP.3.1.1.

Dr. Donald Vinh an infectious disease specialist at McGill University tells Yahoo Canada it’s best to think of KP.2 variant and KP.3 (and future subvariants like KP.3.1.1.) as cousins since they share certain mutations in their spike proteins.

Vinh says the existing vaccines formulated to target KP.2 from Moderna and Pfizer (which is still under review in Canada) have been successful in against their targeted strains. According to Vinh, as KP.3 and its variants continue to circulate, these vaccines “are likely going to have an impact in protecting against clinically important disease.”

“However, the variants are constantly in flux,” he says. “We are hearing about newer variants in other parts of the world that are less related/close to KP.2 or KP.3, and it will not be a surprise if some of these variants predominate, perhaps over the next 3-6 months, and for which the current vaccine formulations may or may not have weakened activity against them.”

What are the symptoms of the KP.3 COVID variant and sub-variants?

In a previous interview with Yahoo Canada, Dr. Isaac Bogoch, an infectious disease specialist said symptoms of FLiRT variants (including KP.3 and its derivatives) are similar or same to those of other Omicron subvariants. "It's probably more of the same," he claimed, adding it's unlikely we'll see any surprises when it comes to symptoms.

COVID-19 symptoms continue to include:

• Sore throat

• Runny nose

• Sneezing

• Cough or cough that worsens

• Shortness of breath

• Difficulty breathing

• Fever

• Chills

• Fatigue

• Muscle or body aches

• Loss of smell or taste

• Headache

• Abdominal pain, diarrhea and vomiting

Is the new Moderna vaccine the same as a booster?

No, the latest COVID vaccine from Moderna is not the same as a booster.

"Booster" shots are extra doses of a vaccine you've already received. Prior to Health Canada's latest approval, Canadians had the option to receive a booster of the previous formulation that targets Omicron XBB.1.5.

The latest formula from Moderna is considered an "updated vaccine" that helps the body build new responses to more recent variants.

What are the current vaccination guidelines in Canada?

Back in May, the National Advisory Committee on Immunization published guidelines that strongly recommended a fall COVID shot for seniors, people with underlying medical conditions and anyone else in a higher-risk group. That includes pregnant people and those living in congregate living settings, like long-term care homes.

NACI added that anyone above 6 months of age who isn't considered high risk "may receive the most recently updated vaccine in the fall of 2024." The organization recommends a six-month interval between COVID vaccines, "with a minimum of three months from the last dose."

Will the current rapid testing detect the new COVID subvariants?

One of the issues with the emerging strains of COVID is detection. Healthcare settings using polymearse chain reaction (PCR) tests are more accurate at identifying the new strains of COVID. However, the rapid antigen tests are different. In a previous interview with Yahoo Canada, Vinh said its possible that some of the rapid tests that were manufactured years ago might not be able to detect the latest strains of COVID.

"It's possible that a person could pick up a rapid test, do it properly, and the test— which isn't expired— comes back negative," he explained. "There are other reasons why the test could be negative, but it's a little bit hit and miss."

These negative tests could potentially transmit the virus to someone at-risk. Wearing masks when you don't feel well around vulnerable persons and practicing social distances are encouraged.

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