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 …