More Ontarians living in designated hot spots for the Delta COVID-19 variant are eligible to book earlier second vaccine doses starting today.

Health units covering Toronto, Peel, Halton, Porcupine, Wellington-Dufferin-Guelph, Waterloo and York, Hamilton, Simcoe-Muskoka and Durham are considered hot spots for the more infectious virus variant.

People in those health units who received a first dose of an mRNA vaccine on or before May 30 can move up their second shots today.

The provincial vaccine booking portal will open to those eligible at 8 a.m. this morning.

The province says sometime next week, all adults who received a first dose of Pfizer-BioNTech or Moderna's product can book a second appointment as soon as 28 days after their initial shot.

Second doses were initially booked four months after the first in Ontario but the province is shortening that timeline as more vaccine is expected in province.