Canada’s National Advisory Committee on Immunization (NACI) released a statement Monday saying it does not currently recommend the use of AstraZeneca for individuals 65 years of age and older due to limited information on its efficacy.
In the statement, NACI said that in clinical trials, COVID-19 vaccines have demonstrated high efficacy (approximately 94%), although the AstraZeneca COVID-19 vaccine has demonstrated an average efficacy of approximately 62% in those 18-64 years of age.
“Protection offered by the first dose of mRNA vaccines is lower than the efficacy achieved after the second dose,” said NACI. “The protection offered by the first dose of the viral vector vaccine is comparable to the efficacy observed after the second dose, with protection lasting until the second dose is administered (up to 12 weeks later).”
NACI noted there “is currently insufficient evidence on the duration of protection and on the efficacy of these vaccines in preventing death, hospitalization, asymptomatic infection and reducing transmission of SARS-CoV-2, although studies are ongoing.”
On Friday, Health Canada announced it had approved two new COVID-19 vaccines, resulting in the country’s third and fourth shots authorized for use across the country.
The federal health agency announced the AstraZeneca vaccine — developed in partnership with Oxford University — and the Serum Institute of India vaccine, India’s version of the AstraZeneca vaccine.
The federal health agency has been reviewing AstraZeneca’s two-dose COVID-19 vaccine since October and the Serum Institute of India since January.
“After thorough, independent reviews of the evidence, the Department has determined that these vaccines meet Canada’s stringent safety, efficacy and quality requirements,” says Health Canada.
The health agency says these are the first viral vector-based COVID-19 vaccines authorized in Canada. The vaccines are authorized for use in people over 18 years of age. They are administered as a two-dose regimen and can be kept at refrigerated temperatures (from 2ºC to 8ºC) for at least six months, facilitating distribution across the country.
At a Friday morning briefing, Supriya Sharma, the senior medical advisor for Health Canada, said the government agency conducted “independent and thorough reviews” for the vaccines, all of which meet Health Canada’s requirements. Sharma says the “benefits of the vaccines outweigh the risks of not taking a vaccine.”
The second doses of the vaccines are to be taken four to 12 weeks after the first shot, and common side effects include tenderness, headaches, muscle pain, fever, and chills.
Sharma says the majority of side effect cases were mild to moderate in terms of severity and were “resolved within a few days.”
Health Canada says the vaccine is 62% effective at preventing cases of COVID-19, overall.
Sharma says Health Canada is working with all manufacturers to assess the AstraZeneca and the Serum Institute of India vaccine’s “efficacy against the COVID-19 variants.”
“With all vaccines, we will take action if any safety issue is identified,” says Sharma.