Williams has said daily new cases should be below 1,000 a day before restrictions are relaxed.
Premier Doug Ford said Thursday that public health measures have been effective in driving down cases, but need to be continued for now. "It's just not good enough. if we get the supply, we will work our backs off to have a two-dose summer".
The province says they will work with public health units to offer both doses of vaccine to youth aged 12 to 17 by the end of August, in collaboration with school boards and other partners.
Neighbouring New Brunswick announced that it had two more cases of the blood clots for a total of four.
In the Thunder Bay District, COVID-19 rates continue to decline and there are 36 cases considered active as of Thursday.
Beginning the week of May 31, youth in Ontario between 12 and 17 years of age and their family members who have not received a vaccine will be eligible to book an appointment to receive their first dose of the Pfizer vaccine, including at special dedicated youth and family clinics throughout the weeks of June 14 and 21.
Chief Medical Officer Dr. David Williams indicated the health science table would like to see well under 1,000 doses a day throughout the province before lifting any current restrictions.
On Thursday, the province reported its lowest test positivity rate (5.7 percent) since April 3.
"The elderly are vulnerable right now with only the one dose", Langer said.
If Rt is greater than 1, it means the outbreak is growing. There are 1,632 people now hospitalized with COVID-19 across the province, including 776 in intensive care.
"We're still at a point where the trajectory is on a downward slope, but it's still taking a while for the numbers to come down", said Dr. Thomas Tenkate, associate professor at the Ryerson School of Occupational and Public Health.
"I think we are still looking at June through July before we start to ease off."
In an interview with Toronto television station CP24, the prime minister said Ottawa has reduced the number of global flights and is open to working with the province to enact more restrictions.
The health minister said the number of hospitalizations and patients in ICUs would have to go down and a backlog of surgeries would have to be worked through before the ban on outdoor sports could be lifted.
The premier issued another letter to Prime Minister Justin Trudeau, arguing additional measures - such as quarantine requirements for travellers coming into Canada by land - are needed to curb the spread of more contagious COVID-19 variants.
Schools will also remain closed to in-person learning, with Ford saying health experts wanting schools to open again, while teacher's unions say schools should remain closed.
The province reported 2,759 new infections in its latest update - well below the more than 4,000 a day it was seeing when it last extended the order and added sweeping restrictions about a month ago.