No ‘elevated risk’ of stroke from Pfizer’s bivalent COVID shot, Health Canada says

Recent data from one U.S. Centers for Disease Control and Prevention (CDC) database has detected a potential stroke risk link in older adults who received an updated Pfizer COVID-19 bivalent shot. However, according to Health Canada (HC) there is currently “no indication” connecting mRNA bivalent vaccines with ischemic strokes.

Ischemic stroke is the most common type of stroke, according to Health Canada’s website. It involves a sudden loss of brain function triggered by a sudden brain blood vessel blockage. This can be caused by a variety of reasons, including smoking, high blood pressure, obesity, diabetes and high blood cholesterol.

Although Health Canada and the Public Health Agency of Canada (PHAC) “are aware” of the recent announcement on the “possible preliminary COVID-19 vaccine safety signal between the Pfizer-BioNTech bivalent COVID-19 vaccine and strokes in people aged 65 and over,” the agency pointed out that “at this time, the CDC is not recommending any changes to vaccination practices.”

In an emailed statement to Global News on Friday, the agency said that as of Jan. 1, over seven million mRNA bivalent vaccines have been administered in Canada but to date, PHAC or HC “have not observed an elevated risk or any signals for thromboembolic events or vascular events” after the administration of these vaccines.

The statement added that the possible link between bivalent Pfizer shots and strokes in older adults has not been observed by any other international regulatory services to date, either.

“Health Canada and PHAC continue to monitor the safety of COVID-19 vaccines approved in Canada to ensure that their benefits continue to outweigh their risks, as is done for all approved vaccines in Canada,” it read.

As the CDC and Food and Drug Administration (FDA) continue to investigate whether there is an association between ischemic stroke and the Pfizer bivalent vaccine for older adults, U.S. health officials on Thursday said that the signal is weaker than what the CDC had flagged earlier in January.

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U.S. FDA officials said they had not detected a link between the shots and strokes in two other safety monitoring databases.

In Canada, less than five reports of ischemic stroke have been submitted to PHAC and HC to date following receipt of an mRNA bivalent vaccine, the email from Canada’s health agency said, and of those, “only one followed the Pfizer-BioNTech bivalent vaccine” that was for “an individual aged 65 years or older.”

“Currently, in Canada, available data shows that there is no indication of a signal related to ischemic stroke and mRNA bivalent vaccines,” it said.

“Although a preliminary signal has been identified by the CDC’s Vaccine Safety Datalink surveillance system, it was not identified by their complementary Vaccine Adverse Event Reporting System,” the agency further clarified in the email.

“The sharing of information of these reports demonstrates that the global post-market monitoring system for vaccines is working.”

The agency assured that Canada has a “robust vaccine safety surveillance system in place that engages healthcare professionals, vaccine manufacturers, and the provincial and territorial health authorities.”

“As safety issues are investigated,” Health Canada will take “appropriate action as needed,” it said.

Since the beginning of the pandemic emergency nearly three years ago, over 50,000 Canadians have died after contracting COVID-19, PHAC confirmed last week.

As of then, the death toll sat at 50,135.

Quebec, which is the only province that still reports COVID-19 data daily, has seen the most confirmed deaths of any jurisdiction with 17,865 fatalities to date. Ontario has the second-highest provincial death toll as of Jan. 20, which sits at 15,786, followed by Alberta at 5,470 deaths as of Jan 18.

— with files from Global News’ Aaron D’Andrea and Sean Boynton