In an online briefing, the WHO’s chief scientist Soumya Swaminathan suggested to reporters that mixing and matching is dangerous because there is not currently enough data to support it.
"It's a little bit of a dangerous trend here. We are in a data-free, evidence-free zone as far as mix and match," Swaminathan said in response to a question about booster shots.
She added that “it will be a chaotic situation in countries if citizens start deciding when and who will be taking a second, a third and a fourth dose."
Canada’s National Advisory Committee on Immunizations, the body that advises federal health officials on vaccines, has said that the Pfizer and Moderna mRNA vaccines against COVID-19 can be used interchangeably when a second dose of the same vaccine is not readily available.
In a statement, a spokesperson for Health Minister Christine Elliott said Ontario plans to continue following the NACI recommendations.
Find out how your rivals rank in organic and paid search