Canada's National Advisory Committee on Immunization Issues Warning Against AstraZeneca COVID-19 Vaccine

Canada's National Advisory Committee on Immunization has recommended the AstraZeneca Covid-19 vaccine should not be used in adults under age 55 while rare cases of serious blood clots following vaccination are being investigated, according to a statement from the committee.

“As Chief Medical Officers of Health, we take vaccine safety very seriously. In Canada there are mechanisms to investigate and share reports of serious adverse events following COVID-19 vaccination to determine if they are causally linked to COVID-19 vaccines. On March 24, 2021 Health Canada issued a label change and guidance on the AstraZeneca COVID-19 vaccine, following European reports of rare but serious cases of blood clots associated with low levels of blood platelets (i.e., thrombocytopenia) following immunization with the AstraZeneca vaccine. Health Canada will be issuing additional terms and conditions requiring AstraZeneca manufacturers to conduct a detailed assessment of the benefits and risks of the vaccine by age and gender in the Canadian context. This information, along with further international evidence, will be used to determine if additional regulatory actions are necessary,” according to a statement released by the Committee. “In the interim, National Advisory Committee on Immunization (NACI) is recommending an immediate pause in the use of the AstraZeneca vaccine in all individuals less than 55 years of age in Canada. This is based on evidence of rare instances of vaccine-induced pro-thrombotic immune thrombocytopenia (VIPIT) following AstraZeneca vaccination reported in Europe, with associated high case fatality and related serious outcomes. As Chief Medical Officers of Health, we are acting decisively with our unified position to pause the use of AstraZeneca vaccine in Canada in those under age 55 at this time. We are taking this precautionary measure while Health Canada as the regulator completes its updated risk/benefit analysis based on emerging data. During this time of risk assessment, Canada has other vaccine options to address the ongoing risk of COVID-19 infection. To date, such adverse events have not been reported in Canada and AstraZeneca vaccine has not yet been used in large numbers in Canada.”

This decision is part of the vaccine safety monitoring and response approach that has long been established in Canada and used to monitor all vaccines, including COVID-19 vaccines.

The Council of Chief Medical Officers of Health includes the Chief Medical Officer of Health from each provincial and territorial jurisdiction, Canada's Chief Public Health Officer, the Chief Medical Advisor of Health Canada, the Chief Medical Officer of Public Health of Indigenous Services Canada, the Chief Medical Officer from the First Nations Health Authority, and ex-officio members from other federal government departments.