No known link for AstraZeneca vaccine and clots

Health Canada's chief medical adviser says there is no scientific explanation to suggest a link between the Oxford-AstraZeneca COVID-19 vaccine and blood clots.

Dr. Supriya Sharma says Health Canada has a "really low threshold" for adverse events that could trigger a pause on the use of a vaccine and wouldn't hesitate to do so if something warranted it.

A few European countries halted use of AstraZeneca's injection temporarily this week, and others suspended use of specific batches, after some adverse events, including blood clots, were reported following vaccination.

Health Canada says the vaccine remains safe and effective but will continue to monitor all adverse events.

Sharma says Health Canada has the reports and is looking for three things, including if there is a biological explanation for how the vaccine could have caused the blood clots.

She says there is none.