Alberta woman in her 50s dies of rare blood clot linked to AstraZeneca vaccine

An Alberta woman in her 50s has died from a rare blood clot condition after receiving the AstraZeneca-Oxford vaccine, says the province's chief medical officer of health.

In a statement Tuesday, Dr. Deena Hinshaw said the woman died of vaccine-induced immune thrombotic thrombocytopenia (VITT). It's Alberta's first death linked to the vaccine.

The woman was not identified to protect the "privacy of the grieving family," Hinshaw said in the statement.

"While any death is tragic, it is important to remember that the risks of dying or suffering other severe outcomes from COVID-19 remain far greater than the risk following AstraZeneca vaccine."

Hinshaw said the woman was only the second confirmed case of VITT in the province. More than 253,000 doses of AstraZeneca or CoviSHIELD that have been administered in Alberta.

Though extremely rare, VITT differs from a typical blood clot because it can cause cerebral venous sinus thrombosis (CVST), where veins that drain blood from the brain are obstructed and can potentially cause fatal bleeding.

The National Advisory Committee on Immunization estimates VITT occurs at a rate of one in 100,000 shots. As of Monday, there were seven reported cases of VITT in Canada and just one other death — a 54-year-old woman from Quebec.

Hinshaw said the risk of COVID-19 is far greater than the risk of VITT.

"Albertans 50 to 59 who are diagnosed with COVID-19 are 350 times more likely to die from that infection than to experience VITT after an AstraZeneca vaccine," she said in the statement.

"They are also at least 1,500 times more likely to be hospitalized from COVID-19 than experiencing VITT after getting AstraZeneca."

In a statement, Alberta Health said Alberta's remaining doses of AstraZeneca are with pharmacies and Alberta Health Services.

"They will continue to be administered," reads the statement issued Wednesday. "This does not change the risk assessment previously communicated to Albertans.

"However, if Albertans currently booked for AstraZeneca wish to reschedule or wait for another vaccine, they are free to do so." 

Health Canada has said the AstraZeneca vaccine meets its strict safety standards, and that it continues to monitor adverse outcomes to ensure the benefits of the vaccine outweigh risks.