Quebec suspends giving doses of AstraZeneca to those under 55, though no issues reported in Canada

·4 min read
Quebec suspends giving doses of AstraZeneca to those under 55, though no issues reported in Canada
In Quebec, 111,000 doses of Covishield have been administered so far. (Paul Chiasson/The Canadian Press - image credit)
In Quebec, 111,000 doses of Covishield have been administered so far. (Paul Chiasson/The Canadian Press - image credit)

Quebec joined other provinces Monday in temporarily suspending use of the AstraZeneca-Oxford COVID-19 vaccine in people under the age of 55, pending further investigation about whether it causes blood clots.

As many as 110,000 does of AstraZeneca, also known as Covishield, have been administered so far in Quebec. Of those, only 6,000 were given to people younger than 55, according to the Health Ministry.

Ministry officials said no incidents of suspected blood clots have been reported among those who have received the vaccine.

"The priority is caution," Health Minister Christian Dubé, 63, said in a tweet after Quebec's decision was announced.

Public Health Director Dr. Horacio Arruda explained that authorities were pausing vaccinations with AstraZeneca to re-examine the balance of risk and benefits for younger people.

"It's still early, but we're not taking any chances," he told Radio-Canada on Monday.

The decision followed discussions with the National Advisory Committee on Immunization, which opted to revise its guidelines on AstraZeneca after additional data emerged from Europe.

Initial results from the European Medicines Agency indicated that one in 1 million people who received the vaccine also developed a particular type of blood clot known as a Vaccine-Induced Prothrombotic Immune Thrombocytopenia.

There was no evidence the vaccine itself was causing the thrombosis but the correlation did prompt experts to examine the relationship more closely.

A more recent German study found a higher incident rate of thrombosis, one in 100,000. That study also provided a plausible, but untested, explanation for the correlation.

It was that second study that moved Quebec's immunization committee to agree to pause distribution of AstraZeneca while scientists go about testing whether there is a causal relationship between the vaccine and the rare cases of thrombosis.

"As a cautionary measure, I think it's better to stop for a certain moment its use in younger people," said Dr. Nicholas Brousseau, a member of Quebec's expert committee that issues recommendations on vaccine use.

Premier François Legault received his first does of a COVID-19 vaccine on Friday.
Premier François Legault received his first does of a COVID-19 vaccine on Friday. (Ryan Remiorz/The Canadian Press)

Brousseau said the cases of thrombosis have occurred mainly in people under the age of 55. There have been fewer incidents among older people and the AstraZeneca vaccine has proven to be very effective at reducing hospitalizations and deaths in those age groups.

"At the moment, the risk of dying is linked to the disease, not the vaccine," he said.

Monitoring will continue

Quebec health officials encouraged all those who have received Covishield to monitor their symptoms for several days after getting the shot.

"Quebec has a high performing vaccine safety surveillance system and excellent expertise in the area. Each reported issue is studied in depth," the ministry said in a statement.

The decision to suspend AstraZeneca came on the same day that Dubé acknowledged that Quebec was in the midst of a third wave of infections, driven mainly by more contagious variants.

WATCH | Public Health Director Horacio Arruda discusses impact of the new AstraZeneca guidelines:

Many public health experts have been critical of recent government decisions to loosen restrictions while infections rates are mounting.

They have also noted that, with greater numbers of older Quebecers at least partially vaccinated, cases and hospitalizations are now concentrated in the younger segments of the population.

Dr. Matthew Oughton, an infectious diseases specialist at Montreal's Jewish General Hospital, suggested the suspension of AstraZeneca might hinder efforts to contain the ongoing wave of infections.

"It's going to make a major dent in the plans to get a large amount of people vaccinated in a way erase the third wave," Oughton said.

He added that the government should consider reimposing some of the restrictions it has lifted in recent days.

Arruda said the suspension would cause slight delays to vaccinating certain groups. "It will have an impact on logistics," he said.

Quebec is currently aiming to offer a first dose to the entire adult population by June 24. Most of the demand in the coming weeks is expected to be filled with the Pfizer and Moderna vaccines, Brousseau said.

Provincial health officials say anyone displaying the following symptoms in the days after receiving the AstraZeneca/Covidshield vaccine should contact a doctor or Info-Santé:

  • severe or persistent headaches

  • vision problems

  • chest pain

  • persistent abdominal pain

  • bruising