A batch of AstraZeneca vaccine under investigation by international health authorities for possible links to blood clots is not part of Alberta's supply.
Dr. Deena Hinshaw, Alberta's chief medical officer of health, issued a statement Thursday assuring Albertans that doses being administered in the province are safe.
The province is relying on a different brand name of the AstraZeneca vaccine, she said, one not associated with the batch triggering precautions overseas.
"I want to assure Albertans that the current doses of COVIShield AstraZeneca vaccine offered in Alberta have not been linked to the side-effects issues reported in some European countries linked to one lot of vaccine," Hinshaw wrote on Twitter.
"We are currently using COVIShield, the brand name of a vaccine produced by the Serum Institute of India that is considered equivalent to AstraZeneca by Health Canada."
Several European countries announced this week they would temporarily suspend the use of AstraZeneca's COVID-19 vaccine after reports that some people who had been vaccinated developed blood clots.
'Extremely rare events'
Hinshaw's assurances came as Alberta further expanded its vaccination campaign, allowing thousands of people to book appointments for their first dose of the province's initial batch of COVIShield's version of the AstraZeneca vaccine.
COVIShield, which was approved for use in Canada on Feb. 26, is safe and effective and will help prevent serious illness, Hinshaw said.
She said Canada has "a robust surveillance system" in place to detect "rare occurrences that may or may not be related" to the AstraZeneca shot.
"It is important to note these are extremely rare events in an area that is using a lot of this vaccine," Hinshaw said on Twitter.
"There is currently no indication that vaccination has caused these events and the actions these countries have taken is out of an abundance of caution. We will continue watching closely and monitoring every dose of the vaccine in Alberta."
Denmark and Norway are the latest European countries to temporarily suspend the use of AstraZeneca. Austria also announced this week that it would stop using a batch of AstraZeneca while investigating a death and an illness.
The lot in question — Batch ABV5300 — comprises one million doses of the vaccine worldwide. According to the European Union investigators and the drug maker, the batch was shipped to 17 EU countries but not to Canada.
'A super-cautious approach'
The suspension of the supply is seen as a precautionary measure, as a direct link between the symptoms and the vaccine remains unconfirmed, and the development of blood clots among those vaccinated has been extremely rare.
Danish health authorities said the country's decision to suspend the shots for two weeks came after a 60-year old woman in Denmark, who was given an AstraZeneca shot from the same batch used in Austria, formed a blood clot and died.
"It is currently not possible to conclude whether there is a link," Health Minister Magnus Heunicke said on Twitter. "We are acting early, it needs to be thoroughly investigated."
Also on Thursday, Italy said it would suspend use of the AstraZeneca batch that was used in Austria.
Four other countries — Estonia, Lithuania, Luxembourg and Latvia — have stopped inoculations from the batch while an investigation continues.
Some health experts said there was little evidence to suggest the AstraZeneca vaccine should not be administered and that the cases of blood clots corresponded with the rate of such cases in the general population.
"This is a super-cautious approach based on some isolated reports in Europe," Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, told Reuters.
"The problem with spontaneous reports of suspected adverse reactions to a vaccine are the enormous difficulty of distinguishing a causal effect from a coincidence," he said, adding that COVID-19 was strongly associated with blood clotting.
The European Union's drug regulator, the European Medicines Agency (EMA), has emphasised there is no indication the vaccine caused blood clots and the likelihood of a defect in the supply was unlikely.
In a statement issued on Wednesday, the EMA said there was no evidence so far linking AstraZeneca to the two cases in Austria.
"There is currently no indication that vaccination has caused these conditions, which are not listed as side effects with this vaccine. Although a quality defect is considered unlikely at this stage, the batch quality is being investigated."
The EMA said it would continue to investigate reports of adverse reactions but their investigation so far shows that the number of blood clots reported in vaccinated people was no higher than in the general population.
In a statement to CBC News, the drug maker said its shots were subject to strict quality controls and there had been "no confirmed serious adverse events associated with the vaccine."
Alberta is following the advice of a national immunization committee and is not offering the AstraZeneca vaccine to people 65 and older, because clinical trials didn't include enough people in that age group to determine efficacy.
"COVIShield /AstraZeneca works," Alberta Health Services said in a statement Thursday. "It has been shown to reduce infection by 60 to 70 percent, and severe outcomes like hospitalization by 80 per cent.
"Vaccines save lives. We continue to strongly encourage Albertans to get the vaccine as soon as they are eligible."