Health Canada has authorized the use of the Novavax COVID-19 vaccine for adults in Canada.

The two-dose Novavax Nuvaxovid vaccine showed 90 per cent effectiveness in protecting clinical trial participants from symptomatic COVID-19, and 100 per cent effectiveness in preventing severe disease, according to a press release from the agency.

Health Canada has been reviewing Novavax’s protein-based COVID-19 vaccine since January 2021.

The vaccine is now authorized in Canada for people who are 18 years of age and older. According to Health Canada's website, the vaccine's safety and effectiveness in children has not yet been established.

Dr. Theresa Tam, Canada’s chief public health officer, said at a technical briefing on Thursday that the Novavax vaccine is the first protein-based COVID-19 vaccine authorized for use in Canada, and will be offered to adults in Canada who have so far been unable or unwilling to receive an mRNA vaccine. Similar protein-based technology is used in hepatitis and influenza vaccines currently on the market.

Health Canada recommends the two doses of the vaccine be given 21 days apart, but the final decision on the dosing schedule is left up to each province and territory. Novavax is not currently recommended as a booster dose, but Tam said that it could be used as a third dose for those who have already received other authorized vaccines as an “off-the-label” use with informed consent.

A full list of the vaccine's ingredients and possible but expected side effects are included on the Health Canada website.

Canada signed a tentative deal with the Maryland-based Novavax Inc. in February 2021 to produce its vaccine at a Montreal facility after the federal government faced mounting pressure over Canada’s depleted domestic vaccine manufacturing capacity.

Tam said a delivery of the Novavax vaccine will arrive in Canada in March from a production facility in India, and that while Canada has contracted a “significant supply” of the vaccine, the federal government will be working with provinces to determine the exact numbers required for fulfillment.

Dr. Supriya Sharma, chief medical adviser at Health Canada, said that the production facility in Montreal needs an inspection from Health Canada before manufacturing activity can take place, and the facility has not indicated that it is ready for that yet.