Due to the small but increasing number of cases of blood clots in overseas patients following AZ vaccination, Canadian experts today recommended a halt to AZ vaccination for people under 55 years of age and asked pharmaceutical companies to assess the benefits and risks of the vaccine based on age and gender.
While each Canadian region is responsible for its own immunization program, Manitoba and Quebec have taken the lead in following new guidelines from Canada‘s National Advisory Committee on Immunization (NACI).
Howard Njoo, Canada’s deputy chief public health officer, said in a press conference that there is still a great deal of uncertainty about the benefits of administering the AstraZeneca-developed 2019 coronavirus disease (COVID-19) vaccine to adults under age 55.
“At this Time, we are halting the administration of the AZ vaccine to adults under 55 years of age pending further risk-benefit analysis.”
In the meantime, officials are urging Canadians who have received AZ vaccine in the past 20 days to consult their physicians.
Health Canada and the National Advisory Committee on Immunization (NACI) physicians said at the briefing that they will ask Astellas to conduct a detailed assessment of the benefits and risks of vaccination based on age and gender.
Europe has reported rare but serious blood clots and hemorrhages after AZ vaccination, with some deaths, mainly in young women. Canada has administered approximately 307,000 doses of AZ vaccine to the population and no such cases have been reported.
Canada’s National Advisory Committee on Immunization (NACI) earlier this month called for the AZ vaccine to be administered only to people aged 18 to 64 years, saying clinical trials did not cover enough older people, and then revised its recommendation to cover people aged 65 and older after reviewing “real-world evidence” of the vaccine’s effectiveness in older people.
Shelley Deeks, vice chair of the National Advisory Committee on Immunization, said most of the observed adverse health effects occurred primarily in women under 55 years of age, between four and 16 weeks after vaccination.
Canada is expected to receive 1.5 million doses of AZ vaccine tomorrow from the United States, which has not yet approved domestic use. In addition, Canada has ordered 20 million doses of AZ vaccine, plus 2 million doses of vaccine manufactured by the Serum Institute of India.