Alberta confirms 1st case of rare blood clot after AstraZeneca vaccine
It is only the second case confirmed in Canada
Alberta has confirmed its first case of a rare blood clot linked to the AstraZeneca vaccine.
The case was identified in a man in his 60s after receiving the vaccine, according to a statement released by Alberta's chief medical officer of health on Saturday.
"While this case is unfortunate, it does not change the risk assessment that I have previously communicated to Albertans," Dr. Deena Hinshaw said during a teleconference.
"These blood clots remain extremely rare, and anyone who is aged 55 and older faces much higher risks from COVID-19 infections than from this vaccine."
The man has received treatment and is recovering. Hinshaw said his symptoms would have begun within the four to 20 day window indicated as the risk-timing period.
She said officials are looking at expanding that window out to 28 days.
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The case marks only the second instance of the rare blood clot in Canada after more than 700,000 doses, Hinshaw said.
The risk of a blood clot from the vaccine is much smaller than taking some medications such as birth control pills, she said.
Alberta is currently offering the AstraZeneca vaccine to Albertans aged 55 and older, following a recommendation last month from the National Advisory Committee on Immunization.
It has not updated its recommendation since Health Canada announced results of a safety review this week that found the vaccine to be safe for all adults.
Higher risk from COVID-19
Hinshaw reiterated comments she made earlier this week about the rarity of these cases, especially compared to the severe outcomes from COVID-19.
She said the global frequency of vaccine-induced immune thrombotic thrombocytopenia (VITT) has been estimated at around one in 100,000 to 250,000 doses of vaccine.
The risk of a blood clot is significantly higher for people who become infected with COVID-19 than for anyone who received the AstraZeneca vaccine, Hinshaw said.
About one in four people hospitalized with the disease get blood clots, she added.
Most of the complications previously identified in Europe occurred within 14 days of receiving the AstraZeneca shot and the majority were in women under the age of 55.
Hinshaw said it's possible those instances could be related to other factors and that while there may be a risk to those who are over 55 or male, it is still a very rare one.
The Public Health Agency of Canada tweeted Saturday that it had received the report of the rare adverse event from the province, saying it demonstrates the country's vaccine safety monitoring works.
Vaccine hesitancy spurred by reports of the extremely rare blood clots has been identified as a factor in low turnouts at mass vaccination clinics in Edmonton and Calgary.
The rapid-flow clinic at the Edmonton Expo Centre can administer 7,000 shots per day at capacity but most days this week did only several hundred.
With files from Paige Parsons and Adam Miller.