Alberta defends vaccine mixing despite WHO booster caution

EDMONTON -

Alberta health officials are defending mixing and matching of COVID-19 vaccines from different manufacturers after the World Health Organization (WHO) said to be cautious about the practice.

Dr. Souya Swaminathan, WHO chief scientist, said on Monday that citizens should be cautious about receiving vaccines from different manufacturers since there is limited data available about the practice.

“We are in a data-free, evidence-free zone as far as mix and match. There is limited data on mix and match,” she said.

The comments were made in reference to booster shots and have created alarm and confusion. CTV News has reached out to the WHO for clarification.

• WHO cautions data still limited on mixing COVID-19 vaccines, but Canadian officials say it's OK

Government and health officials in several countries – including Canada – insist different doses are safe and effective.

Tom McMillan, Alberta Health spokesperson, told CTV News Edmonton in a statement that the province’s own advisory committee on vaccines has said second doses for vaccines can be safely used interchangeably.

“Every Albertan who received different vaccines for their first and second dose should feel good that they are fully immunized and have the greatest protection against all strains of COVID-19,” McMillan said.

“With COVID-19 still a significant health threat around the world, we continue to strongly recommend that everyone book the first appointment available, regardless of the type of vaccine.”

The spokesperson added that there is no evidence that mixing vaccines increases health risks or decreases levels of protection.

“In fact, some emerging evidence indicates that mixing vaccine types may increase protection,” McMillan said.

Dr. Noel Gibney, a critical care physician and co-chair of the Edmonton Zone Medical Staff Association Pandemic Response Committee, told CTV News Edmonton in an email statement that the WHO’s comments are “excessively cautious.”

“There are studies showing improved immune response to vaccination with different COVID vaccines, and my knowledge, no significant side effects,” Gibney said.

“I think it’s one of those situations where perfection is the enemy of good.”

The doctor also noted how other non-COVID-19 vaccines that require booster shots or yearly immunizations are often mixed and matched with few side effects.

As of Monday, 74.1 per cent of Albertans have received at least one dose and 55.3 per cent are fully immunized with both doses.

Alberta Health is not releasing data on the number of people who received specific vaccines, McMillan said.

As of last week, Health Canada said at least 1.3 million Canadians opted to receive mixed doses. Of those who got their second shot between May 31 and June 26, one-in-five got a different vaccine than their first.

With files from The Canadian Press