TORONTO -- Lucy Hunter, who got her second dose at Lawlor Pharmasave on Kingston road in Toronto today, says "I'm feeling much more relieved, now that I have the shot."

New booking eligibility announced this morning allows anyone 70 or older, anyone who received a first dose of mRNA (Pfizer, Moderna) on April 18 or earlier, or anyone who received a first dose of AstraZeneca at least 12 weeks ago can soon book their second shot.

Booking started today for pharmacy and primary care locations and starts June 7 for mass immunization clinics.

Today is also the first day the province is allowing second doses to be a mix of different manufacturers, so the first dose of AstraZeneca can now be matched with a second dose of Pfizer or Moderna.

Hunter received her second dose of AstraZeneca.

"I listened to various people from the Mayor to the Prime Minister, saying that they're willing to have the AstraZeneca second shot and I am too," Hunter told CTV News Toronto.

While others, like Mara Hebberd, who received AstraZeneca as her first dose, are choosing to wait for Pfizer or Moderna.

"Just because my doctor said not to take the risk, since I do have some medical issues," Hebberd said.

Dr. Isaac Bogoch, from the province’s vaccine task force, says we are reaching a time where people can make the best choice for themselves.

"I know there's a lot of people weighing the pros and cons of each approach," he said, adding, "I think that's a smart thing to do right now."

The City of Toronto plans on adding an additional 10,000 appointments at city-run mass vaccination clinics over the next week to accommodate.

Kyro Maseh, owner of Lawlor Pharmasave, says they've had to unplug their phones because of the crush of calls for people trying to book their second shot, with many asking for Pfizer.

He said, "If I had enough supply of Pfizer, I would not hesitate to be administering it to everybody that needs it and qualifies for it."

They only get enough supply of each type of vaccine to cover second doses from the same manufacturer, Maseh said.

But supply is currently ramping up.

"We just went through a replenishment of AstraZeneca to make sure that everyone who wants one at the 12-week mark will get the option for the AstraZeneca," Justin Bates, from the Ontario Pharmacists Association, said.

The delivery schedule shows more mRNA vaccines coming into the province every week, so the choice may become more common in the near future.