Health Canada Authorizes Use of Pfizer Vaccine as a Booster Shot

A vial of Pfizer-BioNTech COVID-19 vaccine is pictured at an Alberta Health Services vaccination clinic in Didsbury, Alta., on June 29, 2021. The Canadian Press/Jeff McIntosh

Health Canada has authorized the Pfizer-BioNTech COVID-19 vaccine to be used as a booster shot for adults 18 years-old and above, saying the shot is designed to help people maintain their protection against the virus over time.

Health Canada said in a statement Tuesday that it had received a submission from Pfizer on Oct. 1 seeking approval for its COVID-19 vaccine to be used as a third or booster dose.

“After a thorough, independent review of the evidence, Health Canada has determined that the Comirnaty COVID-19 vaccine booster shot meets the Department’s stringent safety, efficacy and quality requirements,” the health agency said.

The booster shot can be administered at least six months after a patient received the second vaccine dose.

According to Health Canada’s website, a total of 306 individuals 18 to 55 years of age received the Comirnaty booster dose in a study of the vaccine to support authorization.

“Overall, the findings were that the antibody levels were 3-fold higher after the booster dose relative to levels after the second dose,” the health agency said.

The authorization is in line with recommendations made by the National Advisory Committee on Immunization (NACI), released on Oct. 29, that the booster shot should be offered to certain age groups and individuals, such as long-term care workers and adults 70 and over.

Several provinces announced plans to offer the booster shot ahead of Health Canada’s announcement. Ontario expanded eligibility for the third dose on Nov. 3, while Nova Scotia said on Nov. 5 that it will begin to administer booster doses to “more eligible groups” by the end of November.

Health Canada said provincial health authorities will still need to follow NACI’s guidelines on how to administer the booster shot and who should receive it.

“People in Canada should consult their local public health guidance, informed by the National Advisory Committee on Immunization, for details on which individuals or groups of people are recommended to receive a booster dose at this time,” Health Canada said.

The U.S. vaccine company Moderna has also asked Health Canada to authorize its vaccine to be used as a booster shot. While a review of Moderna’s application is still underway, the federal health agency released a recommendation on Nov. 3 saying its vaccine could be used as the third shot.

“Either Moderna or Pfizer vaccines may be used as a third or booster dose (regardless of which COVID-19 vaccine was used in the primary series),” it said.