The projections were released just hours before Premier Doug Ford was expected to announce a four-week provincewide "shutdown."
It wasn't immediately clear if the shutdown would include a stay-at home order. But last week, the government gave the province's top doctor the power to use the "emergency brake" to shut down regions and enforce restrictions that would see most retail stores shut down and essential services remain open with capacity limits.
The science advisory table also suggested Thursday that limiting inter-provincial movement - similar to the one that was imposed in January and expired starting in mid-February - would help brings the number of new cases down.
Dr. Adalsteinn Brown, co-chair of the group, said short-term case projections will depend entirely on the public health measures implemented by the government and vaccination rates.
"I think if you're unable to get that level of impact, you're not going to see the same reduction in cases, you're not going to see the same control over ICU admissions," Brown said.
Ontario's chief medical officer of health, Dr. David Williams, said the key to controlling spread of the virus will be to limit mobility, especially between regions.
"People moving around from areas of high levels of community transmission, to lower levels .... they also spread variants of concern," he said. "Our big concern with our recommendations (is) ... how do you decrease and limit that kind of mobility so that people will stay home, stay locally?"
Brown said the province's vaccine rollout is not reaching the highest risk communities, hampering its impact as an effective strategy to fight the pandemic.
He also said that 40 per cent of Ontario residents aged 75-79 and 72 per cent of those aged 70-74 still have not received their first dose of the vaccine.
"We are expanding first dose coverage, but it remains incomplete," Brown said.
The spread of variants threatens the province's health system's ability to deal with regular intensive care admissions and care for all patients, he said.
The group said that COVID-19 hospitalizations are up by over 40 per cent over the past two weeks.
Brown said variants of concern are now the dominate strain of the virus in the province.
"Younger Ontarians are ending up in hospital and risk of ICU admission is two times higher and the risk of death is one and a half times higher for patients," he said.
When asked about the upcoming announcement of the new restrictions, Ford said Thursday morning that it was a "tought decision."
“We’ll make the tough decision but it’s the right decision. One thousand per cent, it’s the right decision."
Education Minister Stephen Lecce said Thursday that schools will remain open, as they are critical to student's mental health and learning.
Meanwhile, more than 150 intensive care unit doctors signed an open letter to the government on Thursday, calling for new, stricter, measures.
"The current measures and framework are not working to contain the spread of this virus," reads the letter in part. "Even if we had unlimited ICU capacity, allowing these (variants of concern) to spread exponentially is unethical."
The letter says doctors are seeing younger patients on ventilators and many are parents of school-aged children. It notes people being admitted to intensive care have contracted COVID-19 at work or have followed all the rules and only gone out for groceries.
The Ford government has faced criticism over its failure to offer supports for essential workers, especially in the COVID-19 hot spots, including paid sick days.
