https://www.siliconvalley.com/2021/06/01/covid-canada-oks-mixing-vaccine-brands/

(CNN) — Canada has changed its guidelines on mixing doses of Covid-19 vaccines, the country’s health agency said Tuesday, and Canadians may get a different type of vaccine for their second shot.

The Public Health Agency of Canada said people who received an AstraZeneca vaccine for the first dose may get either a Pfizer or Moderna vaccine for the second dose. People who received one of the two mRNA vaccines — Pfizer’s or Moderna’s — may get either of the two brands for the second dose.