TORONTO -- A group of doctors working in Ontario’s intensive care units are slamming the Ford government, saying the province’s current COVID-19 framework is not working and is allowing the deadly disease to “run free.”

The doctors sent the letter on Thursday urging the government to implement stricter public measures to stop the spread of COVID-19, and to not rely on intensive care unit (ICU) capacity as a benchmark for when change is needed.

“Ontario is at a critical point in the pandemic, and we are being led down a very dangerous path by using ICU capacity as a benchmark for tolerance of COVID-19 spread,” the letter, which was signed by more than 150 doctors, stated.

“We do not agree with this approach and believe new public health measures are required immediately in order to regain control of the pandemic and save lives.”

“Even if we had unlimited ICU capacity, allowing these variants of concern to spread exponentially is unethical.”

The doctors say the new variants of the disease are affecting the province differently. They said that each person who is infected has a higher chance of hospitalization, ICU admission and death.

The latest Critical Care Services Ontario report, obtained by CTV News Toronto on Thursday morning, shows there are currently 430 patients with COVID-19 in ICUs across the province.

The total marks the highest number of COVID-19 patients in critical care at one time since the pandemic began. The last time the ICU admission total surpassed 400 was in January during the height of the pandemic’s second wave.

“We are seeing younger patients on ventilators – many are parents of school-aged children. We are seeing entire families end up in our ICUs,” the doctors said.

“About four in 10 patients who come to the ICU with COVID will die. More than half of patients requiring mechanical ventilation due to COVID will die.”

In response to the surge in ICU cases, Ontario Premier Doug Ford announced a province-wide shutdown on Thursday that will start on Saturday and will last for a month at least.

The shutdown will close in-person dining, gyms and personal care services, and will limit gatherings, but some non-essential businesses, including shopping malls, will remain open with limited capacity.

Dr. Michael Warner, the medical director of critical care at Michael Garron Hospital who also signed Thursday’s letter, told CTV News Toronto that those measures might not be enough to deal with highly transmissible COVID-19 variants.

“Non-essential retail is open. It's no different really from what Toronto and Peel are in now. Will that be effective? Because only the stay-at-home order got cases down in wave two,” Warner said.

“I don’t think it will be enough because it's not the same as what we had to mitigate wave two. The variants are completely different. It's a different pandemic. It's so much more infectious. It's taking down younger people.”

“If we do this kind of half-measure thing it’s going to last longer, ruin our summer potentially, and cause more death … The situation is so critical that unless we put the brakes on the train, it will not slow down.”

In the letter sent out by doctors on Thursday, they urged the government to not choose public health measures solely based on ICU capacity and what hospitals can handle.

“The growth of [variants] in Ontario is exponential. Trying to adjust our public health response to ICU capacity will not break the chains of transmission,” they stated. “Countries attempting this approach faced massive numbers of deaths and had pushed hospital capacity beyond its limit.”

If case numbers continue to grow as they are, the doctors said hospitals will become overwhelmed and will be forced to triage patients and decide who gets care.

“We cannot allow this virus to run free in our population and hope that the expanded ICU capacity and field hospitals are enough,” the letter stated. “Immediate public health interventions are needed today in order to curb transmission and prevent further unnecessary deaths.

“As ICU doctors, we are the last line of defence, and we are ringing the alarm bell.”