OTTAWA — Health Canada has approved AstraZeneca's COVID-19 vaccine, adding a third vaccine to the list available in Canada and potentially speeding up the pace at which Canadians can be vaccinated against the virus.
The vaccine can be used immediately on people over 18, guidance in line with authorizations from the United Kingdom, the European Medicine Agency and the World Health Organization, though several other European countries only allow it to be used on people under the age of 65.
Health Canada's authorization says the clinical trial data was limited for people over 65, but that blood tests showed seniors did produce COVID-19 antibodies from the vaccine.
Also "real world evidence and post-market experience" in places the vaccine is already in use show "a potential benefit and no safety concerns" with giving the vaccine to seniors.
"While this is good news, we must continue to do our best to follow public health guidelines," Health Canada's chief medical adviser Dr. Supriya Sharma said at a news conference Friday.
"We're all in this together and need to remember to keep wearing a mask, washing our hands and keeping our physical distance."
Canada is to get 20 million doses of AstraZeneca between April and September.
The vaccine is administered in two doses, anywhere from four and 12 weeks apart, though some data suggests waiting longer between shots is preferable.
Those doses are manufactured in the United States.
Health Canada also authorized the AstraZeneca vaccine that is being made at the Serum Institute of India. The vaccine is the same but was licensed to Serum and is considered to be distinct because of different manufacturing processes.
The federal government has said it is negotiating to get more doses of AstraZeneca from the Serum Institute, in addition to the 20 million coming from the U.S.
Another 1.9 million doses are also expected before the end of June through the international vaccine-sharing program known as COVAX, with the first 500,000 of those potentially arriving before the end of March. Those doses are made in South Korea.
Canada has been criticized for taking doses from COVAX, when it has so many doses coming from private deals with vaccine makers.
AstraZeneca is the most flexible of the vaccines now approved in Canada, able to be shipped and stored in refrigerators, rather than freezers. Open vials can be saved for up to 48 hours in a refrigerator as long as they haven't been out of the fridge for more than six hours total before being used.
Both Pfizer and Moderna are shipped frozen, with the former requiring ultracold storage in special freezers, and both must be used entirely after a vial is opened.
More than 1.7 million doses of Pfizer-BioNTech and Moderna vaccines have been injected in Canada, with about 700,000 people getting one dose so far, and almost 500,000 now fully vaccinated with two doses.
Before AstraZeneca's approval, Canada anticipated receiving another four million doses of Pfizer and Moderna in March, and hoped to vaccinate at least three million people by the end of the month.
Another 11.5 million people are in line to be vaccinated by the end of June, with the remaining Canadians by September. All of that depends on no further production delays.
A timeline for deliveries of the AstraZeneca vaccine has yet to be released.
The AstraZeneca vaccine works differently than the other two already in use in Canada.
Both Pfizer-BioNTech and Moderna use messenger RNA technology, using RNA encoded with the piece of the SARS-CoV-2 virus known as the spike protein. The mRNA trains the body to fight off a COVID-19 infection. Both were about 95 per cent effective at preventing COVID-19 in clinical trials and reports in Canada have said even one dose has prevented illness in more than 80 per cent of long-term care residents and health-care workers.
AstraZeneca is a viral vector vaccine, which takes a cold virus, modifies it so it can't reproduce itself, and adds the SARs-CoV-2 spike protein. When injected, it too provokes the body to develop infection-fighting antibodies and cells to fight the virus.
Health Canada says it is about 62 per cent effective, with mostly mild and short-lived side-effects like headaches, fatigue and soreness at the injection site.
AstraZeneca will have to submit safety reports.
Health Canada is also reviewing two other vaccines.
Approval of Johnson and Johnson's vaccine will likely not come until early March and Novavax is not expected until April.
This report by The Canadian Press was first published Feb. 26, 2021.
The Canadian Press