Health Canada has approved Pfizer's new bivalent COVID-19 vaccine, which targets the virus strains now most common in Canada.
The updated version of the Pfizer-BioNTech Comirnaty COVID-19 vaccine targets the Omicron BA.4 and BA.5 subvariants, as well as the original strain of the virus, and is authorized for use as a booster dose in people 12 years of age and older.
"The booster is expected to trigger a strong immune response against both the original SARS-CoV-2 strain as well as the Omicron BA.4/BA.5 subvariants," Health Canada said in a media statement.
"It is expected to have a similar safety profile to the original Pfizer-BioNTech Comirnaty vaccine, with mostly mild side effects."
Health Canada said it has imposed terms and conditions on the authorization of the new vaccine, including a requirement that Pfizer-BioNTech provide information to Health Canada on the safety and efficacy of the vaccine on an ongoing basis to ensure its benefits continue to outweigh the risks.
"I'm really excited to have the bivalent vaccines for the different SARS-CoV-2 variants approved," said Alyson Kelvin, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan.
"We're seeing almost all infections worldwide are BA.5, so this is going to offer more protection to people."
Health Canada says 88 per cent of the COVID-19 cases identified in mid-September were BA.5 and nine per cent were BA.4.
Who should get the vaccine
The National Advisory Committee on Immunization (NACI) is recommending that all Canadians 65 years of age or older get the new shot. It also says that Canadians 12 and older who face an elevated risk of severe illness should get the shot as well.
NACI also said Friday that mRNA bivalent COVID-19 vaccines are now the preferred booster shot.
Health Canada officials said that Canadians who have not had a booster for six months should get this new shot as soon as they can. Canadians who have not had a shot for three months should also consider getting the shot.
Health Canada says that those who have had a booster less than three months ago should not rush out to get the shot because it will not be as effective as it would be if they wait a little longer.
Two options for better protection
This is the second combination vaccine approved by Health Canada's vaccine review team and the first that targets BA.4 and BA.5. Last month, Health Canada approved use of Moderna's bivalent COVID-19 vaccine, branded Spikevax, which targets the original virus and the first Omicron variant, BA.1.
Kelvin said the Moderna and Pfizer-BioNTech bivalent shots are expected to offer better protection against the circulating strains.
"It's really important knowing that there is a significant difference in how your immune system sees the Omicron variants compared to the original SARS-CoV-2 virus, that you are at least getting some protection to the Omicron variants," she said.
"I'm really excited to see the potential of these bivalent vaccines and how we might advance mRNA technology going forward."
'I am concerned': Duclos
Canada's Chief Public Health Officer Theresa Tam said that while there was a decline in cases toward the end of the summer, COVID-19 infections are once again on the rise.
She urged Canadians to get the new shot so that when they're spending more time indoors over the winter months, they'll be sufficiently protected from infection and severe illness.
Health Minister Jean-Yves Duclos echoed that call and said the new vaccines will help protect people from developing long COVID over the winter months.
"I am concerned," Duclos said Friday. "From what I'm hearing from the experts, [they] are telling us ... that the coming months, the coming weeks will be critical when it comes to COVID-19 infection and all the consequences this can have for people and health-care workers who are already quite tired."
Canada's Deputy Chief Public Health Officer Dr. Howard Njoo said Friday that he's confident there will be enough of both vaccines to meet Canadian demands.
"If we talk about the Moderna B1 vaccine, there are 10.5 million doses in the country now," he said. "If we are talking about the new Pfizer vaccine, we're expecting next week to have delivery of doses.
"We have a contract for some 12.6 million doses … and between the two I think it's enough in the meantime to cover the expected demand for booster doses."