Health Canada has given the green light to Moderna’s bivalent COVID-19 vaccine, making it the first vaccine specifically targeting the Omicron variant to get approval for the Canadian market.
Health Minister Jean-Yves Duclos says 780,000 doses of the Omicron booster will be arriving in Canada on Friday, with 10.5 million on track to arrive by the end of September.
“This fall will be challenging with the return of the flu and other respiratory diseases, and people moving indoors,” Duclos said. “Only 60 per cent of adult Canadians have received a third dose, putting us behind all other G7 countries except for the United States.”
Increasing that rate from 60 per cent to 90 per cent would reduce hospitalizations from COVID-19 by up to 90 per cent this fall and winter, he added, pointing to the enormous strain on healthcare systems.
“This would support our healthcare workers who are tired and need our health,” Duclos said.
According to the drug authorization listing, the bivalent booster will be a half-dose of the amount delivered in the primary doses of the vaccine, keeping it in line with the dose delivered in boosters so far.
The Omicron booster is authorized only for Canadians over the age of 18 at this time.
Side effects are listed as “mild” and similar to those experienced with the regular booster doses: muscle aches, chills, headache, fever and pain at the injection site.
Health Canada called the approval a “milestone” moment in a press release shortly after the authorization, and said the bivalent booster triggers a “strong” immune response against the original strain of the coronavirus that causes COVID-19 as well as BA.1, the original Omicron variant.
While the booster does not specifically target BA.4 or BA.5 — which is the dominant strain circulating now — Health Canada said clinical data shows the booster still generates “a good immune response against the Omicron BA.4 and BA.5 subvariants, and is expected to extend the durability of protection.”
“The virus will always be one step ahead of us, but we are closing the gap,” said Dr. Supriya Sharma, chief medical advisor with Health Canada, in a briefing on the authorization on Thursday morning.
Dr. Marc Berthiaume, director of the health products branch of Health Canada, described the booster in French as “essentially two vaccines in one.”
Moderna, which submitted its bivalent vaccine candidate to Health Canada in June, said at the time that trial data showed when given as a fourth dose, its variant-adapted shot raised virus-neutralizing antibodies by eight-fold against Omicron.
Ottawa has signed an agreement with Moderna to provide 12 million doses of its updated shot for 2022 and 2023. The two have agreed to convert six million doses of the company’s COVID-19 vaccine, which targets the original virus, to an Omicron-containing bivalent vaccine.
Canada will also purchase an additional 4.5 million doses of the Omicron-containing vaccine, and is moving forward the scheduled delivery of 1.5 million doses of the bivalent shot to 2022 from 2023.
Vaccine effectiveness has taken a hit as the virus has evolved, and vaccine makers have had to work on creating new shots in an effort to boost protection levels. A bivalent vaccine is designed to target two different variants of the same virus.
The United Kingdom became the first country to approve the Moderna bivalent booster last month. The U.S. followed this week, with the Food and Drug Administration authorizing booster doses that specifically target the BA.4 and BA.5 subvariants of Omicron.
Who should get the Omicron booster?
Officials say Health Canada expects to begin receiving applications for boosters targeting BA.4 and BA.5 as early as next week, but that the BA.1 booster is a “good option” for Canadians right now.
Dr. Howard Njoo, Canada’s deputy chief public health officer, said the bivalent vaccine will provide “stronger” and “broader” protection against the Omicron subvariants circulating now.
He urged Canadians who haven’t had a booster in the last six months or who had COVID-19 at least six months ago to get the updated Omicron booster in preparation for “an anticipated increase in COVID-19 activity” in the fall.
He said moving forward, the bivalent booster should be the one offered to anyone over the age of 18 who is due for a booster, unless it is not available. In that case, he said a regular booster can still be offered.
“Shipments will begin arriving over the coming days and months,” Njoo said.
Njoo added provincial fall vaccination programs are expected to begin “shortly” and that there will be enough Omicron boosters for every Canadian over the age of 18 who wants one this fall and winter.
Moving forward, Njoo said Canadians will likely see public health officials and vaccine manufacturers working to regularly update boosters to target the strains that are becoming dominant, in a similar way to how flu shots are updated every year to try to target the strains spreading in communities.
“It’s not a perfect analogy, but that’s where we’re starting to go,” he said.
Omicron booster won't stop but may 'blunt' fall wave: expert
The question now is whether the approval will be enough to slow or stop the expected fall wave.
Public health measures such as masking requirements and the need to isolate after testing positive for COVID-19 have been removed by provincial government like Ontario, and the return to school for children and youth is leading doctors to urge a return to masking in order to reduce infections.
While vaccination significantly lowers the risks of severe illness and death, even mild cases of COVID-19 can lead to what’s become known as “long COVID” and are increasingly raising concerns about potential links between infection and medium or longer term illnesses.
University of Ottawa epidemiologist Raywat Deonandan said the challenge of a wave this fall likely won’t be large-scale death, but rather large-scale hospitalizations and infections along with the associated threat to the Canadian healthcare system, which is already fragile.
“We’re not looking at an existential threat in the sense that people aren’t going to die in great amounts anymore because vaccination has taken the teeth out of the disease in that respect,” he said.
“But the hospitalization rate or hospitalization numbers are going to be higher than normal because more people are getting infected. The fact that so many jurisdictions have removed COVID restrictions means that more people are going to become infected, particularly younger people.”
Deonandan said he expects to see pediatric hospitalizations increase, and that while the Omicron boosters will likely “blunt” a fall wave, they won’t stop it.
And if that happens, it would come at a time when healthcare in many parts of the country is already on what he described as the “verge of collapse.”
“That means you may see situations where people call an ambulance and one doesn’t arrive,” he said.
“That’s my biggest concern right now, is the threat to the health care system, not to individuals necessarily.”
— with files from The Associated Press and Reuters