TORONTO -- Ontario is allowing anyone aged 18 and up who received a first dose of a mRNA vaccine to book their second dose starting next week.

As of 8 a.m. on June 28, all adults who received a first dose of Pfizer or Moderna will become eligible to book their shot ahead of schedule using the provincial system.

According to the province, this will accelerate second dose eligibility for about 1.5 million people in Ontario.

For those who received their first dose this month, there is still a 21-day minimum interval between Pfizer doses and a 28-day minimum interval for Moderna.

“Ontario’s vaccine rollout continues to pick up speed, allowing us to provide more second doses ahead of schedule while supporting our communities most at risk,” Health Minister Christine Elliott said in a statement.

“All vaccines provide strong protection against COVID-19 and the Delta variant, and I encourage everyone to book your second dose appointment as soon as possible.”

Individuals who received a first dose of AstraZeneca must still wait the eight-week interval before getting a second shot of either the same vaccine or a mRNA option.

The province is also allowing youth between the ages of 12 and 17 in one of Ontario’s 10 Delta variant hot spots to book their second dose starting 8 a.m. on June 26.

The hot spots include the Durham, Halton, Hamilton, Peel, Porcupine, Simcoe-Muskoka, Toronto, Waterloo, Wellington-Dufferin-Guelph and York public health units

“To support a safe return to school in September, the province will be looking to accelerate youth second dose bookings following individuals aged 18 and over,” the province said in a news release issued Friday.

As of Wednesday, anyone in a Delta variant hot spots who received their first dose on or before May 30 became eligible for a second dose.

The province says that 230,000 additional doses were provided to Delta hot spots this week to help accelerate second shots in the regions.

In the province's original vaccine rollout, individuals who received their shot after May 30 weren't scheduled to get their second dose until August.

According to officials, more than 76 per cent of Ontario adults have received a first dose of a COVID-19 vaccine and more than 30 per cent have received two shots.