Dr. Theresa Tam said mixing COVID-19 vaccines in Canada for the first and second doses is a "possibility" and could start happening in this country by the summer for those who have received a dose of the AstraZeneca vaccine.

Speaking with CTV News on May 12, she said mixing "will be really helpful, because then it makes subsequent doses easier to administer and predict, given the supply."

Dr. Tam also said Canada is looking "really carefully" at data from a U.K. study about using different vaccines for first and second doses instead of the same for both.

"Early indications look favourable towards the use of an mRNA vaccine, the Pfizer vaccine in this case, after a first dose of AstraZeneca," she said.

During an interview with CP24 on May 13, Justin Trudeau confirmed that Canada is looking at "a mix and match" of vaccines for first and second doses. He also said recently that the country can have a normal summer partly because there's expected to be enough supply for all eligible Canadians to have received their first dose by then.

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