Ontario reported 4,250 new COVID-19 cases on Sunday as well as 18 additional deaths, as overall hospital admissions and ICU occupancy increased to new whole-pandemic highs.

Ontario reported 4,362 new cases of COVID-19 on Saturday, and hospitalizations as counted by the Ministry of Health surpassed 2,000 for the first time in the whole pandemic.

The seven day rolling average of new cases is now 4,341, down slightly from 4,370 yesterday.

The Ministry of Health says there are now 2,107 people being treated for COVID-19 in hospitals, up from 2,065 yesterday.

The number of those in intensive care units grew to 741 from 726 on Saturday. At least 506 people are breathing with the help of a ventilator.

These numbers represent record highs for the entire length of the COVID-19 pandemic in the province. And the Ministry of Health says the total number of COVID-19 patients in hospitals on Sunday may be a low count on Sunday, as roughly 10 per cent of hospitals did not provide it data on occupancy.

Across the GTA, Toronto reported 1,392 new cases, Peel reported 714, York Region reported 483 and Durham reported 279.

Halton Region reported 127 cases while Hamilton reported 151.

Provincial labs processed 53,776 tests in the past 24 hours, 3,000 less than in the previous period, leading to a positivity rate of at least 9.2 per cent.

Another 28,651 specimens remain under investigation.

Last week, a senior Ontario Health official said the hospital system would begin to need to implement last-ditch triage protocols once COVID-related ICU occupancy hit 900.

The Ford government has enacted a number of measures to try to ramp up hospital capacity in recent weeks, including allowing patients to be transferred between facilities without their consent and asking long-term care homes to house patients in beds freed up after that sector sustained nearly 4,000 COVID-19 deaths in the past year, and also ordering doctors and nurses that perform other hospital functions to report to ICUs.

Modelling released last week showed that COVID-19 patients could take up all of Ontario existing 2,000+ ICU beds by May in a worst-case scenario, where a stay-at-home order was lifted on May 6 instead of later in the month.

There are now 41,588 known active cases of novel coronavirus infection in the province, up nearly 10,000 from one week ago.

A total of 7,716 people are known to have died due to COVID-19 infection since March 2020.

In recent days, Public Health Ontario said between 60 to 80 per cent of all positive COVID-19 tests screened positive for a variant of concern, with the B.1.1.7 coronavirus mutation first discovered in England continuing to represent the lion share of all variant cases.

The province says it administered more than 86,000 doses of approved COVID-19 vaccines on Saturday, bringing the total number of shots administered to more than 3.8 million.

More than 345,000 people have now completed a full two-dose inoculation.

The numbers used in this story are found in the Ontario Ministry of Health's COVID-19 Daily Epidemiologic Summary. The number of cases for any city or region may differ slightly from what is reported by the province, because local units report figures at different times.