Ontario Officials Say It’s ‘Very Safe’ To Mix & Match Vaccines After WHO’s Comments

Ontario's top health officials are reassuring the public after the World Health Organization (WHO)'s chief scientist, Dr. Soumya Swaminathan, advised against mixing and matching COVID-19 vaccines.

Ontario's Associate Chief Medical Officer of Health Dr. Barbara Yaffe said in a press conference on Tuesday that the province is following the advice of Canada's National Advisory Committee on Immunization (NACI), "which recommends it is safe to mix these vaccines based on studies from the U.K., from Spain, [and] from Germany."

"They have found that mixing these vaccines is very safe and produces a strong, effective immune response," said Yaffe.

The statement is in response to Swaminathan expressing concern about this approach. "It's a little bit of a dangerous trend here where people are in a data-free, evidence-free zone as far as mix and match. There is limited data on mix and match," she said on Monday. "It will be a chaotic situation in countries if citizens start deciding when and who [...] should be taking a second or third or fourth dose."

Swaminathan later clarified the statement in a tweet. "Individuals should not decide for themselves, public health agencies can, based on available data," she wrote. "Data from mix and match studies of different vaccines are awaited - immunogenicity and safety both need to be evaluated."

Mayor John Tory weighed in on Swaminathan's statement in an interview with CP24 on Wednesday, calling it a "completely unnecessary controversy created by this person in the World Health Organization." The mayor proceeded to call it a "careless statement, careless in the sense that they didn't think through their words and the impact it would have."

"Our experts, locally, provincial, and federal, all said you could mix these vaccines without negative consequence," he said.

NACI deems it safe to use vaccines interchangeably

NACI, a committee of experts that advises federal health officials on vaccines, has deemed it safe to use COVID-19 vaccines interchangeably when a second dose of the same vaccine is not readily available. That being said, NACI recommends that the same vaccine product should be administered if it is available at the time of the second dose appointment.

"No data currently exist on the interchangeability of COVID-19 mRNA vaccines. However, there is no reason to believe that mRNA vaccine series completion with a different authorized mRNA vaccine product will result in any additional safety issues or deficiency in protection," said the committee in its list of recommendations for COVID-19 vaccines.

Health Canada has a robust website with all the latest information on COVID-19 vaccines and can answer any questions you may have.