TORONTO -- Ontario will prioritize age and risk in the second phase of its vaccination plan and will rely on pharmacies to deliver the AstraZeneca vaccine to residents who fit those categories.

The province is set to reveal the long-anticipated next steps of its plan tomorrow, CTV News Toronto has learned, and will outline a quick-paced timeline for vaccines between March and early June.

"It's going to be based on age and at risk," said Health Minister Christine Elliott on Thursday.

"People with certain health conditions will be moved forward as a priority population, people in certain areas of Ontario, where they've had higher than usual transmission of COVID-19."

Sources with knowledge of the plan said while age is the priority, the province will advise public health units to also focus on at-risk groups and communities with the highest rates of transmission, hospitalization and death.

Beginning in April, those living in congregant settings, who suffer from specific health conditions – such as transplant patients, and those living with down syndrome -- and COVID-19 hotspots will be prioritized for the Pfizer and Moderna vaccine.

While those aged 60-64 will be directed to select pharmacies to receive the AstraZeneca vaccine in March, before the expected shipment of 190,000 doses expires on April 2.

Sources said the government will also prioritize essential service workers who cannot work from home in June, while the final phase of the campaign would begin in August.

The timelines, however, are subject to change as additional vaccines are approved by Health Canada.

Elliott said the government had to recalibrate its timelines after receiving approval from the National Advisory Committee on Immunization to extend the dosage interval by up to 16 weeks, and said the timeline to receive an initial dose would be shortened.

"We were looking at the end of the summer, probably into September," Elliott told reporters at Queen's Park. "But it's fair to say that we will be able to shorten that timeline."