Canadian health officials say they are to stop offering AstraZeneca's Covid-19 vaccine to people under age 55 and require a new analysis of the shot's risks and benefits based on age and gender.
The moves follow reports from Europe of rare but serious blood clots, bleeding and in some cases death after vaccination, mainly in young women. No such cases have been reported in Canada, with about 307,000 AstraZeneca doses administered.
The National Advisory Council of Immunization (NACI), an independent expert panel, said on Monday that the rate at which the clotting complication happens was not yet clear. So far, 40 per cent of people who have developed it have died, but that may fall as more cases are identified and treated early, it said.
“From what is known at this time, there is substantial uncertainty about the benefit of providing AstraZeneca Covid-19 vaccine to adults under 55 years of age,” the council said in a written recommendation.
Older people face a greater risk of hospitalisation and death from Covid-19, and the complication seems to be more rare in that age group, NACI said, so they can be offered the vaccine “with informed consent.”
In response to NACI's guidance, Canada's Council of Chief Medical Officers of Health, which includes provincial and federal representatives, said it would pause the vaccine for those under 55.
The council said it considered the fact that Canada had other vaccines available when making the decision. Most of Canada's supply has so far come from Pfizer and Moderna.
Some 11.8% of Canada's population has received at least one dose of a Covid-19 vaccine, according to Reuters.
Separately, Health Canada, the country's drug regulator, said it would add terms and conditions to the AstraZeneca vaccine's authorisations, including “a requirement that the manufacturers conduct a detailed assessment of the benefits and risks of the vaccine by age and sex in the Canadian context.”
Health Canada said it had been in talks with AstraZeneca, and once it has the requested information, it "will determine if additional regulatory actions are necessary."
It was not immediately clear how long the assessment might take.
“Patient safety remains the company's highest priority,” Carlo Mastrangelo, AstraZeneca Canada's head of corporate affairs, said in a statement. “We continue to work closely with Health Canada to share and submit safety data as it becomes available.”
More doses expected
The pause affects both versions of the vaccine approved in Canada: One granted to AstraZeneca Canada, and a second for the Serum Institute of India (SII) – which is manufacturing its own version of the vaccine under license – and its Canadian partner, Verity Pharmaceuticals.
Many European countries briefly stopped using the Anglo-Swedish firm's vaccine while investigating the blood clot incidents earlier this month, but Canada continued to administer doses.
Nearly all countries have since resumed use of the vaccine. But France broke with guidance from the European medical regulator and said on March 19th it should only be given to people aged 55 or older. France said the decision was based on evidence that the clotting affected younger people.
Canada is expecting a further 1.5 million doses of the AstraZeneca vaccine this week from the United States, which has not yet authorised its use. Canada has ordered more than 20 million doses from AstraZeneca and SII.
COVID-19 cases have been rising in Canada in recent weeks. On Monday, British Columbia halted indoor dining and indoor group fitness classes through April 19, as case counts hit an all-time daily high.
Officials said the measures were a “circuit breaker,” to stop the spread of Covid-19 variants in the province. British Columbia has identified 270 cases of the P1 variant first identified in Brazil, which officials worry is more resistant to vaccines.