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AstraZeneca has initiated the worldwide withdrawal of its COVID-19 vaccine because of a “surplus of available updated vaccines,” and it has requested that the European authorization for its COVID-19 vaccine be pulled. While most countries ceased using the shot in 2021, this move Tuesday makes that cessation official.

Does the withdrawal mean anything for Canadians who got the vaccine? Here’s what you need to know.

AstraZeneca in Canada

AstraZeneca’s COVID-19 vaccine was first approved in Canada on Feb. 26, 2021, a month after approval from the European Medicines Agency in January, 2021. Within weeks, however, concerns grew about the vaccine’s safety, when dozens of countries suspended the vaccine’s use after unusual but rare blood clots were detected in a small number of immunized people.

Canada’s National Advisory Committee on Immunization called for a pause in injections of the AstraZeneca shot to anyone under 55 on Monday March 29, 2021, a day before the country was scheduled to receive 1.5 million doses of the vaccine from the United States.

At that time, about 307,000 AstraZeneca doses had been administered. As of June 11, 2021, there had been one case of capillary leak syndrome, a rare blood clot, after vaccination with the AstraZeneca or COVISHIELD COVID-19 vaccine in Canada.

On May 11, 2021, Ontario and Alberta paused the use of AstraZeneca as a first dose. Ontario stated it was due to an increase in thrombosis with thrombocytopenia syndrome – blood clots which can block blood flow and cause damage to organs, and a lower than normal number of platelets in the blood, which is dangerous because platelets help your body from forming clots – linked to the AstraZeneca vaccine. The change was also made because Canada had the luxury of relying on two other shots for its mass vaccination campaign.

In July, 2021, Health Canada updated the label for the AstraZeneca and COVISHIELD COVID-19 vaccines to add capillary leak syndrome, a rare and serious condition where the small blood vessels start to leak fluid, as a potential side-effect. The agency also included a warning for patients with a history of the syndrome to not get those vaccines.

On Dec. 19, 2023, authorization for AstraZeneca was cancelled under the Food and Drug Regulations at the request of the manufacturer.

How many Canadians were given AstraZeneca Vaccines?

As of Feb. 25, Canada has administered 105,605,632 COVID-19 vaccines. Of those, 2,811,963 or 2.66 per cent of them were AstraZeneca.

How many Canadians experienced negative side effects from AstraZeneca?

As of Jan. 5, 58,712 adverse vaccine events have been reported in Canada. Of those, 3,318 were nonserious complications from AstraZeneca, the most common being headache, fatigue and fever. There were 122 serious complications from AstraZeneca such as cardiac arrest, cardiac failure, myocarditis, pulmonary embolism, Bell’s palsy and thrombosis with thrombocytopenia syndrome (TTS). The majority of adverse symptoms from COVID-19 vaccines started between five minutes and 113 days after vaccination.

Legal challenges and payouts for AstraZeneca and other vaccines

AstraZeneca is being sued by a few different parties. A British man, Jamie Scott, is suing AstraZeneca for what he says is damage caused by the jab in April, 2021. Another British woman, Kam Miller, is suing after her husband, Neil Miller, 50, developed fatal blood clotting after receiving the jab in March, 2021. Miller told the BBC she was not anti-vaccination, but is arguing the compensation she received following his death should be increased.

Canada has a Vaccine Injury Support Program, set up to help people who experienced a serious and permanent injury as a result of receiving a Health Canada authorized vaccine, administered in Canada on or after Dec. 8, 2020. The program was established to ensure no-fault compensation for those affected by vaccine injuries. Health columnist André Picard, writing about the idea in 2019, noted that “vaccination is the cornerstone of public health and compensating the rare cases where vaccines cause injury is the fair and just thing to do.”

The program began accepting claims on June 1, 2021, and as of December, 2023, had given out $11,236,314 to claimants. Vaccine side effects and injuries reported to the database are self-reported, with no confirmation that the injuries were caused by vaccines.

What are the current COVID-19 vaccines available for Canadians?

Several vaccines for COVID-19 are authorized and available for use in Canada. These include messenger ribonucleic acid (mRNA) vaccines, which are preferred, and a protein subunit vaccine. The XBB. 1.5 vaccines are now the recommended products. There are three vaccines currently approved for use by Health Canada:

  • Pfizer-BioNTech Comirnaty XBB (also known as Pfizer) – mRNA vaccine
  • Moderna Spikevax XBB (also known as Moderna) – mRNA vaccine
  • Novavax XBB COVID-19 vaccine (also known as Novavax) – protein subunit vaccine

How does the risk of blood clots compare after a COVID-19 infection vs. from the AstraZeneca vaccine?

A study by researchers in Britain found that people infected with COVID-19 are at least nine times more likely to develop potentially deadly blood conditions compared with those who have received either the Oxford-AstraZeneca or the Pfizer-BioNTech vaccines.

The study, led by a team at the University of Oxford, involved analyzing medical data from 29.1 million people in England who received one dose of vaccine from Dec. 1, 2020, to April 24, 2021. The scientists also looked at medical records for 1.8 million people who tested positive for COVID-19 during that period.

Dr. Seema Marwaha, an assistant professor of internal medicine at the University of Toronto, says that one in five patients hospitalized with COVID-19 actually develop blood clots.

“I have looked after multiple patients who have had COVID-related strokes and COVID-related pulmonary embolisms [blood clots in the lungs],” Dr. Marwaha said. None of these patients had been vaccinated.

“So, your risk of getting a serious clot from COVID is significant.”

Are Canadians who received the AstraZeneca vaccine at risk?

Evidence indicates that the benefits of COVID-19 vaccines continue to outweigh the risks of the disease.

Dr. Michelle Sholzberg, head of the division of hematology-oncology at St. Michael’s Hospital in Toronto, said that clots due to AstraZeneca tended to develop between four and 30 days after the vaccination.

If you were symptom-free after 30 days, “the odds are that you are in the clear,” she added.

Since no Canadians have received the AstraZeneca vaccine since its cancellation in December, 2023, it’s unlikely that anyone would develop new serious side effects now.

What are symptoms associated with blood clot formation

First and foremost, it’s important to keep in mind that vaccine-related blood clots are extremely rare.

The range of symptoms include:

  • A severe headache that does not go away;
  • Neurological problems such as blurred vision, difficulty speaking and seizures;
  • Shortness of breath, chest pain, severe abdominal pain and severe back pain;
  • Severe swelling, pain, colour changes, or coldness in an arm or a leg;
  • Multiple small bruises, red or purple spots or blood blisters under the skin.

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