Health Canada changes AstraZeneca vaccine label to add information about blood clots

Health Canadais updating the label on the AstraZeneca-Oxford and CovishieldCOVID-19 vaccinesto add information about "very rare reports of blood clots associated with low levels of blood platelets," but says the shot remains safe and that the benefits of getting the vaccineoutweigh the risks.

"HealthCanadareassures Canadians that the AstraZeneca COVID-19 vaccine continues to be safe and effective at protecting them against COVID-19 and encourages people to get immunized with any of the COVID-19 vaccines that are authorized inCanada," the agency said in a statement Wednesday evening.

It has alsoissuedguidancefor health-care professionals and vaccine recipients on the potential symptoms to monitorincluding shortness of breath, chest pain, leg swelling and persistent abdominal painor a sudden onset of severe or persistent worsening headaches or blurred vision.

No reports of clots in Canada

All of Canada's current supply of the AstraZeneca-Oxford vaccine is manufactured by the Serum Institute of India, which secured separate regulatory approvals from Health Canada.

That version, which is biologically identical to the AstraZeneca shot but manufactured under different conditions, has been branded as Covishield.

"Health Canada has assessed the available data on the reported events and has determined that the AstraZeneca COVID-19 Vaccine and COVISHIELD (the version of the AstraZeneca COVID-19 Vaccine manufactured by the Serum Institute of India that is currently being distributed in Canada) have not been associated with an increase in the overall risk of thrombosis," the regulator wrote.

WATCH: Recommendations on vaccine not changing,Health Canada says:

Sharma says federal recommendations on AstraZeneca vaccine are not changing

4 years ago

Duration 1:40

Dr. Supriya Sharma, Health Canadas chief medical adviser, says federal recommendations on the use of AstraZeneca's COVID-19 vaccine are not changing at this point in time.

Health Canada says there have been no reports of clots following administration of the AstraZeneca-Oxford vaccine in this country.

Several European countries suspended administration of the AstraZeneca-Oxford vaccine following reports of blood clots in a small number of patients.

The European Medicines Agency (EMA) last week amended its authorization of the vaccine to say there is no overall increase in the risk of blood clots after getting the vaccine but added a warning that a small number of patients had developed rare blood clots in the brain after getting it.

At the time the EMA couldn't say if the clots were related to the vaccine. German and Norwegian scientists have since said in a very small number of patients the vaccine is causing an extreme immune response that is leading to the clots. It is a treatable condition, they said.

The EMA reported 18 cases of cerebral venous sinus thrombosis, out of about 20 million people who received the AstraZeneca-Oxford vaccine in Europe and the United Kingdomand seven cases of another type of clotting disorder related to very low platelet counts.

HealthCanada said it is aware that researchers inEuropehave indicated that they have identified a possible cause for these very rare events, but says little information is available about the findings.

"We have been discussing the rare reports of blood clots and low platelet counts with the European Medicines Agency and other regulators," Dr. Supriya Sharma,Canada's chief medical adviser, said on Thursday."Health Canada will make decisions for Canada based on the science and evidence."

In Canada, provinces have administered over 300,000 doses of Covishield,and Sharma said Health Canada has not received any domestic reports of rare clotting events.

Canada has sofar received about 500,000 doses of the vaccine and expects to get 1.5 million more as soon as this week from the United States.

Health Canada says minor and temporary side effects are common after all vaccinations, but that people should seek medical attention if they experience any new or worsening symptoms.