Federal health officials suspending the use of AstraZeneca COVID-19 vaccine in anyone under age 55

Move based on reports of blood clotting in Europe

Citing reports of blood clotting in Europe, the National Advisory Committee on Immunization has suspended the administering of AstraZeneca’s COVID-19 vaccine to anyone under age 55.

Rare cases of serious blood clots, including cerebral venous sinus thrombosis, have been recently reported in Europe following the use of the AstraZeneca COVID-19 vaccine, according to the NACI, and primarily in women under the age of 55. Clots occurred between 4 and 16 days after receipt of the vaccine.

Health officials say the exact mechanism by which the AstraZeneca vaccine triggers these clots is under investigation. There has been no clotting as a result of the vaccine reported in Canada, but the NACI says a risk assessment has led to the suspension of injections for those under 55. “Adults 55 years of age and older may still be offered the AstraZeneca vaccine with informed consent, given the increased risk of hospitalization and death due to COVID-19 disease in this population,” reads a statement from the NACI.

While this will impact the rate at which the Canadian population can be immunized, the NACI points out the AstraZeneca version made up only a small proportion of all the COVID-19 vaccines available for use in Canada. The NACI says it will continue to monitor and assess risk based on emerging data.