Health Canada authorizes first bivalent COVID-19 booster, doses to start arriving Friday

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OTTAWA — Health Canada has authorized the use of the country's first variant-targeting COVID-19 booster shot, marking what health officials are calling a "milestone" in Canada's pandemic response.

On Thursday, the federal health regulator announced it has given the green light to Moderna's Omicron-targeting bivalent COVID-19 vaccine, for those ages 18 years and older.

The "Spikevax Bivalent" booster dose is an adapted version of the original Moderna mRNA vaccine, and targets both the original strain of COVID-19 as well as the Omicron variant.

"It's essentially two vaccines in one," said Canada's chief medical adviser Dr. Supriya Sharma. "This booster is also intended to extend the durability of protection. This will help us face the next wave."

The mutated and highly-transmissible version of the novel coronavirus and its subvariants has been circulating in Canada since November 2021, currently making up the majority of new cases.

Health Canada said, according to a study comparing individuals immunized with the bivalent shot and those who received the original Moderna mRNA dose, the findings indicated that the updated vaccine "provides better immune response to the Omicron BA.1."

Moderna submitted its bivalent booster to Health Canada for regulatory approval on June 30.

"After a thorough and independent scientific review of the evidence, Health Canada has determined that the bivalent Moderna Spikevax booster is safe and effective," said the health agency. "It was also found to generate a good immune response against the Omicron BA.4 and BA.5 subvariants."

This news came ahead of Health Minister Jean-Yves Duclos's afternoon announcement about "the importance of COVID-19 vaccination as we head into the fall." Duclos said that an initial 780,000 doses of Moderna's bivalent vaccine will begin arriving in Canada on Friday, with more than 10 million more coming by the end of September.

"Since vaccine protection decreases over time, it is important to stay up to date," said Deputy Chief Public Health Officer Dr. Howard Njoo. "If it has been six months since your last dose, or six months since being infected with COVID-19, get another booster dose."

Asked what he'd say to Canadians who may be feeling overwhelmed by the evolving vaccine options, Njoo said people should know there is nothing wrong with the original COVID-19 vaccines offered, either as a primary vaccinations series or as booster doses.

WHO SHOULD RECEIVE THIS SHOT?

According to authorization information published by Health Canada, the proposed dosing regimen is an interval of "at least four months following a primary series and/or previous booster dose."

The National Advisory Committee on Immunization (NACI) issued guidance Thursday, stating that adults 18 years of age and older who are recommended to receive a fall booster dose, should be offered a shot of the bivalent vaccine. This is what NACI has categorized as a "strong" recommendation.

However, NACI said those who are eligible for a booster this fall and are at highest risk "should not delay their planned vaccination in anticipation of a bivalent Omicron-containing COVID-19 vaccine," as the original mRNA vaccines will still offer timely protection.

While the booster shot was submitted by Moderna for approval for ages 12 and over, Health Canada has decided to limit its authorization for use in adults.

Despite this, NACI said Thursday that adolescents 12 to 17 years of age with "moderately to severely immunocompromising conditions and/or who have biological or social risk factors that place them at high risk of severe outcomes" could be offered a shot of the bivalent booster "off-label." This is what NACI has categorized as a "discretionary" recommendation

NACI said that while there is no data on the efficacy, immunogenicity or safety of this booster in individuals under 18 years of age, the benefit of it may "outweigh any potential risks that are unknown at this time."

Given as an intramuscular injection — consistent with other COVID-19 vaccines — the 50 microgram dose can cause common side effects including pain, swelling or redness at the injection site, as well as fatigue, muscle aches and stiffness, fever, and chills.

The federal health agency is cautioning against receiving this shot if you have had an allergic reaction to a previous dose of Moderna's COVID-19 vaccine.

PFIZER BIVALENT UNDER REVIEW

Moderna's bivalent shot will be the first such vaccine available in Canada. Pfizer-BioNTech has also submitted its bivalent booster for regulatory assessment. That submission went to Canada’s federal health regulator on July 25, and authorization could be imminent.

Sharma said Health Canada has also reached out to both pharmaceutical companies to request that they file submissions for vaccines specifically targeting Omicron's BA.4 and BA.5 subvariants, "to ensure we have as many options as possible" as the virus continues to change.

These submissions are expected to be received within the next few weeks, Sharma said.

Thursday's Moderna bivalent authorization comes on the heels of the U.S. Food and Drug Administration granting emergency use authorizations on Wednesday, to both Moderna and Pfizer's bivalent vaccines for use as single booster doses at least two months following primary or booster vaccination.

The United Kingdom approved the Moderna bivalent vaccine on Aug. 15.

As has been the case with previous COVID-19 vaccine authorizations, Health Canada has placed terms and conditions on the authorization, requiring the pharmaceutical giant to continue providing safety and efficacy information.

12 MILLION DOSES PURCHASED

The federal government has already purchased 12 million doses of the vaccine, making an agreement with Moderna to replace some of the planned supply of the original mRNA shot with the newer version, with delivery expected before the end of the year.

As has been the case throughout the pandemic, provincial health authorities will be responsible for determining their rollout of this shot, and who will be prioritized to receive it.

"Canada is well positioned to offer a robust bivalent booster campaign, and shipments will begin arriving over the coming days and months," said Njoo. "Please check your provincial, territorial, or local health authority website for information on when the vaccine will be available in your area."

"The exact timing of the booster doses and appropriate populations to administer booster doses to will depend on a variety of factors, including the local epidemiological contexts which are continually evolving and may vary between provinces and territories," said Health Canada in its regulatory decision summary.

With pandemic restrictions largely lifted across provinces, and Canadians expected to increasingly spend more time indoors, doctors and epidemiologists are cautioning against a rise in COVID-19 cases this fall and winter.