Canada’s National Advisory Committee on Immunization has now formally recommended that the AstraZeneca COVID-19 vaccine should not be used on adults under 55 years of age.

In a statement shared on March 29, the committee cited concerns related to reports of blood clots as its reason for issuing the updated guidance.

Editor's Choice: More Canadian Provinces Have Suspended The AstraZeneca Vaccine For Residents Under 55

The notice explained that “rare cases of serious blood clots, including cerebral venous sinus thrombosis, associated with thrombocytopenia have been recently reported in Europe following post-licensure use of AstraZeneca COVID-19 vaccine.”

The NACI said that the cases identified so far in Europe have been primarily in women under 55 years old, but noted that cases in men have also been reported.

“The rate of this adverse event is still to be confirmed,” the committee explained.

“Based on information from the European Medicines Agency on March 18, 2021 it was originally estimated at approximately 1 per 1,000,000 people vaccinated with the AstraZeneca vaccine, however a higher rate of 1 per 100,000 was reported by the Paul-Ehrlich Institut in Germany.”

What happens next?

Multiple provinces, including P.E.I., Alberta, Manitoba, Ontario and Quebec, have already confirmed they will follow the NACI’s recommendation.

Health Canada will carry out an updated benefit/risk analysis based on emerging data related to the AstraZeneca vaccine.

The NACI’s advice may be updated again depending on the agency’s findings.

The updated guidance comes as Canada is expected to receive 1.5 million doses of the vaccine from the U.S. this week.

However, the committee reassures Canadians that the country is set to receive sufficient doses of other COVID-19 vaccines, ensuring that “vaccinations will not be significantly delayed without using AstraZeneca COVID-19 vaccine in younger adults.”

What about people over 55 years old?

While the AstraZeneca vaccine is not recommended for people under the age of 55 right now, older adults may still be offered the shot with informed consent.

The NACI says this is due to the older population’s “increased risk of hospitalization and death due to COVID-19 disease” and because blood clots appear to be a rarer event in that age group.

Dr. Caroline Quach-Thanh, the chair of NACI, told CBC News that older Canadians should take whatever vaccine they're offered because contracting COVID-19 poses a greater health risk to them than the chance of developing a post-vaccine blood clot.

Health Canada has a robust website with all the latest information on the vaccines and can answer any questions you may have. Click here for more information.