BARRIE, ONT. -- Starting Monday, Simcoe County residents who received the AstraZeneca vaccine can book their second shot eight weeks after getting their first dose.

Previously the Ontario government had set a 12-week minimum wait for people who received AstraZeneca.

"We need to get people fully immunized if we're going to fight the delta variant," says Dr. Sohail Gandhi, the past president of the Ontario Medical Association who now practices in Stayner. "So this is really huge, and I'm really glad to see it, and frankly, I'm glad to see that we've got the supply of vaccines to do it."

People can also choose if they want a second dose of AstraZeneca or switch to Pfizer or Moderna.

Eligible people can book COVID-19 vaccine appointments through the provincial booking system or local health units.

The team at Pro-Health Pharmacy in Barrie says its phone lines were busy this morning, with many eager to rebook their second dose.

"So currently, we are giving Moderna vaccines," says pharmacist Shamshad Mansuri. "But I just got a fax today that I'll be getting more doses of Astrazeneca as well, so the people who got Astrazeneca they will have an option to choose either-or."

Also, as of Monday morning, second does appointments are being escalated in seven regions in the province where the highly transmissible delta variant is circulating. One of those is York Region, where new pop-up clinics are being planned in order to meet demand.

"The uptake has been phenomenal," says Dr. Karim Kurji, the medical officer of health for York Region.

"We have already vaccinated almost 20 per cent of individuals for their second doses."

This morning there were approximately 18,600 new appointments available in York Region. However, the website had more than 28,000 concurrent users.

Meanwhile, Stevenson Memorial Hospital in Alliston is reducing the hours of its COVID-19 assessment centre from 9 a.m. to 5 p.m. Mondays, Wednesdays and Fridays.

Ontario recorded another 530 cases of COVID-19 yesterday.

With files from the Canadian Press