Health Canada has authorized an adapted version of the Moderna vaccine, known as a “bivalent” vaccine which targets the original virus from 2019 and the Omicron variant. It is now authorized for use as a booster dose in Canadians 18 and older. Bivalent basically means the shot is encoded with spike proteins from both versions of the virus.

A statement from Health Canada says this is the first bivalent COVID vaccine authorized in this country, and it marks a milestone in Canada’s response to the virus. Clinical trials indicate a strong immune response against the original COVID-19 virus, along with Omicron and its subvariants, and Health Canada says it is expected to extend the durability of protection. The adapted vaccine has a similar safety profile to the previously approved Moderna Spikevax booster, with the same mild adverse reactions that resolved quickly.