Vaccine expiry change based on science: experts

Many immunologists and infectious disease experts say it is a normal, and scientifically sound decision to extend the expiration date on vaccine doses.

Health Canada is adding another month to the shelf life of thousands of doses of the Oxford-AstraZeneca vaccine that were due to expire in Ontario today.

Dr. Allison McGeer, an infectious disease consultant at Mount Sinai Hospital in Toronto, says expiry dates on vaccines are usually very conservative at first until the product has been around long enough to know when it will start to degrade.

She says she has complete faith that Health Canada's decision was based on testing and sound science.

Timothy Caulfield, Canada Research Chair in health law and policy at the University of Alberta, says the key to keeping this decision from undermining vaccine confidence is communicating it effectively and transparently.

Caulfield says anything that creates doubt about the safety of COVID-19 vaccines could hurt Canada's need to get herd immunity.