TORONTO -- The Ontario government has issued a statement after the World Health Organization’s chief scientist called mixing COVID-19 vaccines a "dangerous trend."

The World Health Organization's Chief Scientist Dr. Soumya Swaminathan said on Monday that she advised against people mixing and matching COVID-19 vaccines from different manufacturers.

The comments were made by Swaminathan while she was discussing booster doses of the COVID-19 vaccine during an online briefing. 

"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.

"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."

In a statement to CTV News Toronto on Monday, Carly Luis, the director of communications for Health Minister Christine Elliott, said Ontario will continue mixing vaccine doses.

"Ontario continues to follow the advice of the National Advisory Committee on Immunization (NACI), which recommends that it is safe to mix vaccines based on studies from the UK, Spain and Germany that have found that mixing vaccines is safe and produces a strong immune response," Luis said. 

"The health and safety of Ontarians remains our top priority, and we will continue to monitor the data working with NACI and the federal government."

Ontario has been mixing COVID-19 vaccines for several weeks, allowing mRNA vaccines to be given interchangeably. Those who received AstraZeneca as a first dose are also able to take an mRNA as their second dose. 

NACI says mixing brands of approved vaccines is safe and effective. 

In a tweet following Monday’s online briefing, Swaminathan said that "individuals should not decide for themselves" to mix vaccine doses, but that "public health agencies can, based on available data."

"Data from mix and match studies of different vaccines are awaited - immunogenicity and safety both need to be evaluated."

In a Ministry of Health document provided to health-care workers in June, the Ontario government said there is "no reason to believe" that mixing COVID-19 would result in any addition safety issues or reduction in protection. 

With files from Reuters.