Canada on Tuesday recommended mixing and matching of AstraZeneca, Pfizer and Moderna COVID-19 vaccines.
The National Advisory Committee on Immunization (NACI) updated its guidance to provinces and territories on mixing and matching second doses of COVID-19 vaccines and advised Canadians to combine either the AstraZeneca-Oxford, Pfizer-BioNTech or Moderna shots interchangeably in certain situations.
NACI guidance is based on early research from UK, Spain that shows mixing shots of AstraZeneca and Pfizer vaccines was both safe and effective at preventing COVID-19.
It recommended that a first shot of the AstraZeneca vaccine can be followed by either Moderna or Pfizer.
For Canadians who have had a first dose of Moderna or Pfizer, NACI recommended they can now take either of the two shots as a second dose -- because they both use a similar mRNA technology -- if the same first dose is unavailable or unknown.
More than 13 million people have received at least one dose of the Pfizer vaccine in Canada, in contrast to over 3.5 million of the Moderna vaccine and more than 2.1 million of the AstraZeneca vaccine as of May 22.