TORONTO -- Ahead of the anticipated arrival of more COVID-19 vaccine doses in the coming weeks, the province has now confirmed who will be prioritized next for its vaccination program.

In a memo sent out to local medical officers of health and hospital CEOs on Sunday, provincial officials said staff and essential caregivers in long-term care homes, high-risk retirement homes and First Nations elder care homes, along with any residents in these settings who have not yet received a first dose, are an "immediate priority" for vaccination.

"The provincial target of providing a first dose offer of vaccine to residents of all long-term care homes and high-risk retirement homes is arriving at completion. This includes work underway to make vaccinations available to First Nations elder care homes across the province," the memo read.

"At this time, we are pleased to report that residents at all long-term care homes across the province have been given an opportunity for their first dose of COVID-19 vaccine."

The groups that should be next in line, according to the province, include Indigenous adults in northern remote and higher risk communities and health-care workers with the highest risk of exposure to COVID-19.

The province has broken down health-care workers into four categories: highest priority, very high priority, high priority, and moderate priority.

Highest-priority health-care workers include all hospital and acute care staff in frontline roles with COVID-19 patients or those with a high-risk of exposure, including workers who perform "aerosol-generating procedures."

Other workers identified in the highest priority group include "all patient-facing health-care workers involved in the COVID-19 response," medical first-responders, including paramedics and firefighters, and community health-care workers serving specialized populations, including those who work at needle exchange or supervised consumption sites.

The province has identified "very high priority" health-care workers as those who work in acute care and other hospital settings not already identified in the previous category, along those who work in congregate and community care settings, including community health centres, birth centres, dentistry clinics, pharmacies, and walk-in clinics.

High priority health-care workers include those who work in community care settings with a lower risk of exposure, including mental health and addiction services and campus health-care workers.

Non-frontline health-care workers, including those who work remotely and do not require personal protective equipment, have been placed in the "moderate priority" category, the memo states.

The province said it has broken down health-care workers into these four categories due to the fact that demand for the vaccine will "initially exceed available supply," which may result in the need to decide who gets the vaccine first. Highest priority health-care workers and very high priority health-care workers have been identified as groups who should be vaccinated "immediately."

"When all reasonable steps have been taken to complete first-dose vaccinations of all staff, essential caregivers and residents of long-term care homes, high-risk retirement homes and First Nations elder care homes, first-dose vaccinations may be made available to the remainder of the Phase One populations," the province said in its memo.

People in this category include all adults ages 80 and over as well as staff, residents, and caregivers in all retirement homes and other congregate care settings for seniors. All Indigenous adults, adult recipients of chronic home care, and health-care workers in the "high" priority level are also included in Phase One.

"To ensure equity and integrity in vaccine delivery, public health units and vaccination clinics should implement processes to fill last-minute cancellations, 'no-shows' and end-of-day remaining doses with people who are in groups identified in this memo as immediate and next priority for vaccination, and only to Phase One priority populations," the memo read.

This directive comes after the head of Ontario's COVID-19 vaccine task force admitted that hospitals gave some doses of the vaccine to non-frontline staff, including people working from home, because it was better to do that than to let the doses expire when people did not show up for their shot.

The province has also confirmed that in an effort to increase the number of first doses it administers during this "supply-limited time," second doses of the Pfizer-BioNTech COVID-19 vaccine will be administered no later than 42 days after the first shot.

This applies to all who receive their first dose with the exception of residents of long-term care, high-risk retirement and First Nations elder care homes, those 80 and older, and residents in other types of congregate care homes for seniors. Those groups will receive the second dose between 21 and 27 days after their first.

Only two COVID-19 vaccines, the Pfizer-BioNTech and Moderna vaccines produced in Europe, are approved for use in Canada and both companies have come up short in their recent shipments to the country.

About 922,234 people in Canada have received at least one dose of a COVID-19 vaccine, approximately 2.43 per cent of the country's population.

But the federal government has indicated that Canada expects to ramp up its vaccination effort this spring when the country receives an influx in vaccines next month.

Pfizer has promised to deliver on its goal to ship four million doses to Canada by the end of March.

In Ontario, an estimated 467,626 doses have been administered and 174,643 people are now fully vaccinated.