BARRIE, ONT. -- York Region's top doctor is asking the province to open up AstraZeneca vaccinations to younger residents in hot spots where infection rates are through the roof.

Right now, the National Advisory Committee on Immunization (NACI) recommends the shot only be administered to those 55 years of age and older.

"Some countries like the U.K. are using it for age 30 upwards. If Ontario wanted to be conservative, we could go to the same as the U.K. strategy," said Dr. Karim Kurji.

Kurji notes Health Canada has approved the vaccine for use in adults 18 years of age and older.

"There would be many, many more people who would want to use AstraZeneca. So that would certainly assist us is our hotspots where many of the pharmacies are located in order to bring down the case we are seeing."

Kurji notes that Vaughan has four of the region's five hot spot postal codes, with the fifth in Markham.

Dr. Kurji said about 500 outbreaks have occurred in area manufacturing facilities, where carpooling continues. Employee screening and use of protective gear have been insufficient and led to staff reporting to work with symptoms.

"We now feel that it is necessary really to vaccinate all folks there because these are the sites where you get continuous outbreaks, and when you get outbreaks there, they tend to circle back into the community one way or another," Kurji said

He is also seeing an increase in the number of people in their 50s with the virus dying.

At the Royal Victoria Regional Health Centre (RVH) in Barrie, 43 patients are being treated for COVID-19. Fourteen patients are in the ICU, 13 on ventilators.

The region is on pace to see more than 700 cases this week, infection rates having tripled this month.

In Grey Bruce, the medical officer of health has asked residents to stay home for 48 hours to allow public health staff to get a handle on how many people may have come into contact with infected residents to limit spread in the community.

Dr. Ian Arra called case management and contact tracing a tool that keeps the pandemic from spiralling out of control.

Until last month, the region saw an average of two cases per day. This week, it is averaging 30. Dr. Arra said pandemic fatigue has worn on residents, and the vaccine supply has to catch up with variants of concern.

With schools closed, doses meant for local teachers and school staff over the weekend have been deferred until next week.

The health unit's mobile units began vaccinating residents in shelters and community living facilities where the risk is highest.

"We're prepared for the worst and hoping for the best," said Dr. Arra.