Health Canada has approved Moderna's updated COVID-19 vaccine for all Canadians who are six months of age and older — while two other options for fall shots remain in the regulatory pipeline.
Federal officials announced the approval on Tuesday morning, more than two months after Moderna submitted its new formulation. The mRNA-based shot is monovalent, targeting just the Omicron XBB.1.5 subvariant, which means the vaccine is more tailored to the virus strains currently circulating.
"I know we all wish COVID-19 no longer existed, but people are still getting infected, and vaccination continues to be one of the most effective ways to protect ourselves against serious outcomes," said Dr. Supriya Sharma, chief medical advisor at Health Canada, during a technical briefing.
Health Canada said Canadians age five and up should receive one dose, regardless of their COVID vaccination history. Meanwhile children from six months to four years old should receive two doses if they have not been previously vaccinated with a COVID vaccine, or one dose if they've previously had at least one dose.
Notably, federal officials aren't calling the shots boosters but instead stressed that these are updated options more similar to an annual flu shot. The COVID situation hasn't stabilized quite yet, Sharma said.
"The idea is we'll get to a place where it will be much more like the flu vaccines where people may be on a regular schedule, getting an updated vaccine," she said.
As for the best time to get another COVID shot, the department suggests waiting six months after your last dose since protection against infection does wane over time — though scientists say protection against serious illness is longer-lasting.
Extra caution for vulnerable, essential workers
On Tuesday, Canada's national vaccine advisory body also reaffirmed its advice from earlier this summer, stressing that vaccination is particularly important for anyone at an increased risk of severe disease, including seniors age 65 and up, residents of congregate living settings such as long-term care facilities, pregnant individuals and anyone with underlying medical conditions who may heightened their risk.
The guidance also applies to people who provide essential community services and members of racialized, First Nations, Métis and Inuit communities.
Health Canada is still reviewing submissions on a "priority basis" for updated shots from other drugmakers as well, including Pfizer-BioNTech's Omicron XBB.1.5 vaccine for Canadians age six months and up and Novavax's shot for people age 12 and up.
"We will have enough supply of the updated COVID-19 vaccines to support immunization programs across Canada," said Canada's chief public health officer, Dr. Theresa Tam, at the federal briefing.
'We will have enough supply of the updated COVID-19 vaccines to support immunization programs across Canada,' said Canada’s chief public health officer, Dr. Theresa Tam, shown here at a Jan. 2021 press conference. (Adrian Wyld/The Canadian Press)
Officials expect 'improved immune response'
Dr. Lynora Saxinger, an infectious diseases specialist at the University of Alberta in Edmonton, said even if Canadians have "booster fatigue," these types of updated vaccines will be important shots to get this fall.
"The original strain now is kind of irrelevant to what's circulating," she said. "But the XBB booster covers most of the important mutations that we're seeing in the alphabet soup of variants that everyone's watching right now.
"So it stands to provide significantly increased protection against infection again."
Tam said preliminary clinical data has shown promising immune responses from the XBB.1.5 vaccine against various Omicron sublineages, including EG.5 and BA.2.86.
She said there are no signals of increased disease severity from these subvariants.
"This improved immune response is expected to better protect against the strains that are circulating in our communities."
Case, hospitalizations climbing
The push for new COVID shots comes amid a rise in cases heading into the fall, as country-wide hospitalizations are also climbing, hitting more than 2,000 by early September — though the number remains far lower than the highest peaks of the pandemic.
Physicians are hopeful that a fall booster campaign could further suppress virus transmission during what's expected to be another busy respiratory virus season.
"You have this kind of undulating risk going on depending when you were last infected or boosted," said Saxinger. "This will provide a real jump — hopefully — on the immunity against infection as well.
"And that could actually make a bigger difference for reducing transmission and kind of flattening the curve for the fall."
Tam stressed that it's difficult to predict what will happen this fall and winter regarding the co-circulation of multiple viruses, including influenza and RSV, given that it is still early in the season.
"But the good news is we can get prepared and protect ourselves in case simultaneous surges of respiratory viruses occur," she said.
Canadians can safely get both their flu and COVID shots during the same appointment, Tam said.
U.S. has approved both Moderna, Pfizer shots
The first COVID vaccines in 2020 were monovalent, or single-target vaccines, aimed at the original strain of the virus. They were followed by bivalent COVID vaccine booster shots that targeted both the original virus and an Omicron strains. The latest shots, again, are monovalent.
Canada's approval of the Moderna shot follows the U.S. Food and Drug Administration (FDA) authorizing updated COVID vaccines from both Pfizer and Moderna the day before, with an advisory panel also set to recommend today whether the shots should be given broadly, or just to specific at-risk populations.
U.S. Centers for Disease Control and Prevention director Mandy Cohen will make the final decision some time after the committee's vote and may or may not follow the panel's advice.
Much like here in Canada, COVID infections and hospitalizations have been rising in the United States, Europe and Asia but remain well below previous peaks, in part thanks to widespread global immunity developed through several years of prior infections and vaccinations.