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A new COVID-19 mRNA vaccine designed to protect against Omicron variants was approved by Health Canada on Thursday. Unlike previous versions of the vaccine, however, this new shot is called a “bivalent vaccine” – one that contains two different versions of the SARS-CoV-2 virus. Naturally, you might have a lot of questions about what that means for you and your family. We have you covered.

What are bivalent vaccines?

Bivalent vaccines are vaccines that contain the genetic information of both the ancestral (or original) strain of a virus and a new, more recent strain. In the case of COVID-19, that means the progenitor virus variants (such as Beta, Gamma and Delta) that kicked off the pandemic and the new, more transmissible Omicron strain that has become the most dominant form of coronavirus worldwide.

The bivalent booster vaccine approved by Health Canada today is being manufactured by Moderna. A bivalent shot from Pfizer was also approved by the Food and Drug Administration in the U.S., but Health Canada has not given it the green light yet.

How is this vaccine different?

Kelly Grindrod, an associate professor at the University of Waterloo’s School of Pharmacy, said the first COVID-19 vaccines were based on the original coronavirus strain that was believed to have originated in Wuhan, China, in 2019.

The bivalent vaccine in Canada, however, will protect against both the original coronavirus, and the first version of the Omicron variant, also known as BA.1.

Dr. Grindrod said bivalent vaccines are similar to existing flu shots, which can protect against multiple different variants of influenza in the same shot.

She added that it’s possible there could be more types of COVID-19 vaccines in the future, and pointed out that the U.S. recently approved a vaccine for newer strains of the Omicron variant that are circulating more heavily than BA.1 right now.

Even though the new bivalent vaccine that is coming to Canada isn’t specifically modelled on the most recent COVID-19 strains, BA.4 and BA.5, Dr. Grindrod said it’s believed they will help further boost immunity.

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Who should get a bivalent vaccine?

Anyone 18 and older who wants a booster shot will be eligible to receive a bivalent vaccine. Some 12-17 year olds with higher social or biological risks, or who are moderately or severely immunocompromised, can receive the bivalent vaccine. Children 11 and younger will have to opt for a regular booster shot for the time being.

To get a bivalent shot, a minimum of six months needs to have passed since a person’s last vaccination or infection with SARS-CoV-2. The National Advisory Committee on Immunization (NACI) says that window can be shortened to three months in cases of “heightened epidemiologic risk.” A combination of previous infection with an Omicron strain and a bivalent booster is said to offer greater protection than one or the other.

In general, bivalent shots are expected to quickly phase out existing booster vaccine stock, with 12 million doses already ordered, and Health Canada has said that there will be enough shots for everyone who wants one.

Those wondering whether they should wait for the bivalent version rather than opting for the current vaccine, NACI is recommending people “carefully consider their individual risk.” People who are at risk of severe outcomes “should not delay their planned vaccination in anticipation of a bivalent Omicron-containing COVID-19 vaccine.”

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When and where will bivalent vaccines be available?

Dr. Grindrod said the answer to this question will differ between jurisdictions, but the rollout of the new bivalent vaccines is imminent.

“We’re seeing that they’re going to start shipping this new vaccine into the country shortly,” she said.

“It’s possible we’ll see it in the next couple weeks or month.”

British Columbia’s Ministry of Health said Thursday that the B.C. government is ready to start distributing the new bivalent vaccine as soon as it receives it from the federal government.

“We expect the vaccines to come over several weeks and most people should be able to get one in September or October,” read a statement from the ministry, which added that more specific information about the rollout would come next week.

“As before, the vaccines will be available in health authority clinics and pharmacies.”

Ontario’s Health Ministry has also said it is making preparations so that the new vaccines can be distributed as soon as they’re received from the federal government.

As to whether people should wait to get the new bivalent vaccine rather than the old one, Dr. Grindrod advised people to hold tight to get a better idea of exactly how long the rollout will take.

Why do bivalent vaccines matter?

Besides being an attempt to protect against the ever evolving Omicron variant, bivalent shots will be a test of waning public messaging amid a fall of uncertainty.

According to Dr. Tania Watts, professor of immunology at the University of Toronto, the combination of governments such as Ontario’s eliminating mandatory isolation periods for individuals infected with COVID-19, children going back to school during a flu season without masking, and overall fatigue from a three-year-long pandemic dragging down vaccination rates will pose an immense challenge for the public health care system.

“The concern is that a lot of people didn’t get their third shot, and even less got their four shots. We don’t know how many are going to go out and get boosted with messaging that it’s not a big deal any more,” Dr. Watts said.

Dr. Grindrod said it’s likely we’ll continue to see new vaccines that are based on the ever-evolving strains of COVID-19.

As jurisdictions start to look at COVID-19 vaccine campaigns as a more long-term effort, Dr. Grindrod also said officials will closely consider the timing for booster rollouts. She said that while vaccines offer long-term protection from hospitalization, they also can protect against contracting COVID-19 in the first place for a couple months.

Timing the booster doses could be an effective strategy during peak seasons, she said.

Editor’s note: An earlier version of this article incorrectly described Omicron as a more virulent strain of the COVID-19 virus. In fact, it is less virulent, but more easily transmissible. The article has been updated.

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