TORONTO -- Ontario is accelerating second COVID-19 vaccine doses for more residents next week.

Anyone who received their first shot of an mRNA vaccine on or before May 9 can book a second dose starting Monday.

Residents of 10 Delta variant hot spots who got first shots on or before May 30 can book second doses starting Wednesday.

Those regions are Toronto, Peel, Halton, Porcupine, Wellington-Dufferin-Guelph, Waterloo and York, and the newly designated hot spots Hamilton, Simcoe-Muskoka and Durham.

People with one vaccine dose are believed to be less protected against the Delta variant, which is also considered far more transmissible than other strains.

All adults in the province who got their first dose on or after May 10 can book an earlier second shot starting the week of June 28.