Health Canada has approved a booster of Pfizer-BioNTech’s COVID-19 vaccine for people over the age of 18.

The booster is designed to help people with their first two COVID-19 vaccine doses maintain their protection against the virus over time.

The booster is identical to the regular Pfizer-BioNTech vaccine, and is to be administered at least six months after the first two vaccine doses.

Different provinces have employed different rollout strategies for booster doses, and mRNA vaccines like Pfizer-BioNTech have already been used to offer longer-lasting protection to high-risk people in several parts of the country.

The National Advisory Committee on Immunization says there is no evidence of waning protection against over time against severe COVID-19 in the general vaccinated population.

However N.A.C.I. has recommended boosters for several high risk groups, including those of advanced age and front-line workers in health care.