Vaccine was developed to target the initial strain of Omicron, which is no longer dominant
Health Canada has formally approved Moderna's updated COVID-19 vaccine targeting the Omicron variant.
It has been approved for use in adults 18 and older.
In a decision summary made public Thursday, Health Canada said the new vaccine shows "significantly higher responses" to the Omicron BA.1 virus in comparison to Moderna's original coronavirus vaccine, officially branded as Spikevax.
While the updated vaccine was developed to target the Omicron BA.1 variant, Health Canada says clinical trials suggest the new vaccine still elicits a "stronger immune response" against the more recent mutations of Omicron — BA.4 and BA.5 — which are now dominant.
"Results of exploratory analyses suggest that a second booster with Spikevax Bivalent would provide a superior neutralizing antibody response against BA.4/5 compared to a second booster with Spikevax Original," reads a portion of the decision.
Health Canada also reports that "no new safety concerns have been identified in studies when compared to the currently approved Spikevax mRNA vaccine."
The National Advisory Committee on Immunization recommends that the updated vaccine be offered to adults who are recommended to receive a fall booster dose.
NACI says adolescents between 12 and 17 with "moderately to severely immunocompromising conditions" and those who have elevated social risk factors could also be offered the vaccine.
WATCH: Health Canada's Chief Medical Advisor Dr. Supriya Sharma says the updated vaccine will be effective against Omicron
Health Canada authorizes Moderna's bivalent COVID-19 vaccine
Health Canada's Chief Medical Advisor Dr. Supriya Sharma says Moderna's new bivalent vaccine will target both the old variant of COVID-19 as well as Omicron, the more recent one. It has been approved for use in Canadians 18 years and older.
The updated vaccine is a combination of two strains, also known as "bivalent" shots. It contains both the original vaccine formulation and protection against the original Omicron variant BA.1.
The new Moderna shot will be delivered in 50 microgram doses. Half of its contents target the original coronavirus strain while the other half target Omicron.
Deputy Chief Public Health Officer Dr. Howard Njoo said there will be enough doses of the updated vaccine for all adults in need of a booster dose this fall and winter. Shipments to the provinces and territories are set to begin next week.
Vaccines for newer Omicron strains may be coming
Both Moderna and Pfizer have developed even newer bivalent vaccines targeting the Omicron BA.4 and BA.5 strains, but the companies have not yet submitted those products for approval by Health Canada.
Njoo said that in choosing to approve Moderna's BA.1-focused vaccine, the government considered the tools it has now "versus what might potentially happen in the future."
"At the end of the day, we're very comfortable with the fact that we have a good bivalent vaccine," Njoo added.
The U.S. Food and Drug Administration announced Wednesday its approval of bivalent vaccines by Pfizer and Moderna that specifically target the more recent Omicron BA.4 and BA.5 strains.
Dr. Supriya Sharma, the chief medical adviser with Health Canada, said the agency expects to receive a submission from Pfizer as soon as next week for a bivalent vaccine targeting BA.4 and BA.5.
A new submission by Moderna for BA.4 and BA.5 is also expected within the next two weeks, Sharma said.
A spokesperson for Pfizer Canada told CBC News Wednesday that its submission to Health Canada for a BA.1-targeted bivalent vaccine is still under review and approval has not yet been granted.
ABOUT THE AUTHOR
Nick Boisvert is a multimedia journalist at the CBC's Parliamentary Bureau in Ottawa. He previously covered municipal politics for CBC News in Toronto. You can reach him at firstname.lastname@example.org.
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