NACI's recommendations on taking a different vaccine as a second dose were issued, which is the kind of evidence-based approach WHO's chief scientist is advocating.
Canada has been mixing and matching COVID-19 vaccines for weeks based on emerging research from Spain and the United Kingdom that found combining AstraZeneca with Pfizer shots was both safe and effective at preventing COVID-19. Because Moderna and Pfizer are both mRNA vaccines, NACI also said that they could be used interchangeably.
"Similar vaccines from different manufacturers are used when vaccine supply or public health programs change. Different vaccine products have been used to complete a vaccine series for influenza, hepatitis A and others."