TORONTO -- Moderna’s Spikevax COVID-19 vaccine has been authorized by Health Canada as a booster shot for adults aged 18 and over, the agency said on Friday.
The booster shot, which is a half dose of the regular vaccine at 50 μg, should be given at least six months after the individual has been fully vaccinated.
The news comes days after Pfizer-BioNTech’s Comirnaty vaccine was approved as a booster for those over the age of 18, though third doses were already being given to high-risk groups across the country.
The Pfizer-BioNTech booster dose is identical to the regular one and should also be administered at least six months after the first two doses.
The booster shot is meant to help those who have already been fully vaccinated maintain their protection against dying or becoming severely sick and hospitalized due to the SARS-CoV-2 virus and its variants, including the Delta variant.
There is some evidence of waning protection over time and provinces and territories across Canada have all begun the process of recommending a booster dose to high-risk groups including residents in long-term care homes, health-care workers, and those who are immunocompromised.
• COVID-19 vaccine booster eligibility by province and territory in Canada
Previously, the National Advisory Committee on Immunization had also recommended an mRNA booster for people who received two doses of Oxford-AstraZeneca or one dose of the Janssen vaccine.
Health Canada said the Moderna vaccine booster shot met all safety, efficacy and quality requirements, following an independent review.
According to the company, the approval was supported by the Phase 2 clinical study, which found that neutralizing antibody titers had waned by six months, particularly against variants of concern, for participants who got a booster shot six to eight months after their second shot. The third dose helped boost neutralizing titers “significantly above the Phase 3 benchmark,” the company said, adding that the side effects and safety of the booster dose was similar to what was observed following the second shot.
