BARRIE, ONT. -- Ontario recently changed the guidelines to allow mixing COVID-19 vaccine doses, but many residents still question whether or not it's wise.

York Region's top doctor promotes getting the first available shot.

"It is preferable to have the same brand of vaccine according to the National Advisory Committee on Immunization, but when that is not readily available, it's perfectly fine and perfectly safe to have another mRNA vaccine," said Dr. Karim Kurji.

The region's medical officer of health said York Region received 29,000 Pfizer vaccines this week and is administering around 10,000 shots per day.

However, as shipments decrease, residents may have to accept the second dose of another vaccine brand.

"We do expect some reduced shipments as of July 5," said Dr. Kurji.

Around 23 per cent of the York Region population remains unvaccinated, according to Dr. Kurji. He hopes pop-up clinics and a presentation this week at council will push people to get their shot.

"This is a very significant issue for us because when we look at the deaths from COVID-19, the vast, vast majority of the individuals who are dying are the individuals who are not vaccinated," said Kurji.

With the emergence of the Delta COVID-19 variant in Ontario, Dr. Kurji stressed the importance of getting the vaccines to avoid severe symptoms from the virus. Although, after handling 44 cases of the variant in recent weeks, Dr. Kurji said most have recovered.

"I'm not particularity concerned about the Delta variant in York Region, frankly," said Dr. Kurji. "Given the fact that we have a high proportion of individuals receiving their first dose and we have about 32 per cent receiving their second dose and these numbers are rising."

Dr. Kurji said although York Region hasn't been hit hard by the Delta variant, areas such as Waterloo have, which he said is likely stalling the province's reopening plans because of the risk of it spreading.