The test positivity rate is 9.1 per cent, down from 9.7 per cent a day ago.
2,152 people are now hospitalized with COVID-19 in Ontario, down from 2,201 reported yesterday.
"The key is to get as many people vaccinated as quickly as possible", Williams said.
Hospitals reported caring for 2,167 patients with COVID-19 including 886 patients in intensive care and 609 patients on ventilators.
At the London Health Sciences Centre (LHSC), there are 92 inpatients with COVID-19, of which 37 are in critical care.
One Toronto-area region said on the weekend it would open up more bookings for those who live or work in hot spots starting Tuesday, but warned it was limited by supply issues.
Health Minister Christine Elliott says there are 985 new cases in Toronto, 714 in Peel Region, and 351 in York Region.
Several other regions reported new infection totals in the triple digits, including Durham Region (147), Hamilton (128), Ottawa (112), and Halton Region (101).
Sunday's announcement confirmed a plan outlined last week appears to be proceeding as expected.
281 cases of B.1.351 (also known as the South African variant).
69,442 lab-confirmed cases of the United Kingdom variant strain of COVID-19 (B.1.1.7).
Ontario does not now report how many cases of the B.1.617 variant, originally found in India, are found in the province.
As of 8 p.m. on April 30, the province reported 5,247,684 doses of vaccine against COVID-19 have been administered.
Ontario extended the interval between doses earlier this year during a period of slow vaccine supply to Canada, making some exceptions for certain at-risk individuals.
Dr. Barbara Yaffe, Ontario's associate medical officer of health, said Monday that the province had asked the National Advisory Committee on Immunization to make recommendations about potentially mixing vaccines.
On Monday, people 18 and older living in the 114 specific neighbourhoods, which have been designated as COVID-19 hot spots, were able to book their vaccine using the provincial booking system for the first time.
The numbers used in this story are found in the Ontario Ministry of Health's COVID-19 Daily Epidemiologic Summary.