Health Canada is updating the label on the AstraZeneca-Oxford and Covishield COVID-19 vaccines to 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 vaccine outweigh the risks.
“Health Canada reassures 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 in Canada,” the agency said in a statement Wednesday evening.
It has also issued guidance for health-care professionals and vaccine recipients on the potential symptoms to monitor — including shortness of breath, chest pain, leg swelling and persistent abdominal pain — or a sudden onset of severe or persistent worsening headaches or blurred vision.
No reports of clots in Canada
That version, which is biologically identical to the AstraZeneca shot but manufactured under different conditions, has been branded as Covishield.
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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, the United Kingdom, and India, and seven cases of another type of clotting disorder related to very low platelet counts.
Health Canada said it is aware that researchers in Europe have indicated that they have identified a possible cause for these very rare events, but says little information is available about the findings. “Health Canada will be reviewing this evidence when available,” it said in the statement.
Canada has so far 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.