BARRIE, ONT. -- Dr. Barry Nathanson isn't mincing his words as he urges residents to heed the warnings from public health during the third wave of COVID-19.

"This is really a very different experience, this wave," the chief of staff at Stevenson Memorial Hospital in Alliston said. "It's not something to be trifled with. It is as dangerous as we've been saying, and people must start to get that message."

Nathanson expressed his disappointment after seeing busy shopping malls this past weekend first-hand while he shuttled life-saving equipment from one medical centre to another.

"Malls filled to the brim, with people either waiting in line or going inside for things that can't be all that critical. And that's where this virus is being spread," he said. "And those cases we're going to see, together with cases that arise from Easter gatherings, Passover gatherings, two weeks from now. Those are the things that need to change."

Nathanson said he's witnessed multiple patients die after contracting COVID-19. "I've lost twenty patients or more, just to this one disease."

Now, with the province in the third wave of the pandemic, the Alliston doctor said the hospital is at or near capacity, "The impact is quite significant," he said. Nathanson noted having to postpone surgeries for COVID cases.

He said the hospital is capable of providing acute care but remains concerned about incoming cases.

"The vast majority of cases are coming from family gatherings, community engagements… all those things that we've been seeing for now, well over a year, are very dangerous, and people should, in their own best interest, and in the interest of our community, be deferring until a later date, a later month, a later time, a when things are safe."

Nathanson warns the third wave is proving grave for a new group of vulnerable people. "We're seeing younger people, and we're seeing people younger who get sicker much more quickly."

In Barrie, Royal Victoria Regional Health Centre currently has 19 COVID-19 positive patients, 14 of whom are in the intensive care unit, five on ventilators.

And in Orillia, Soldiers' Memorial Hospital is at or near capacity, with five of its eight ICU beds occupied.

The Simcoe Muskoka District Health Unit isn't reporting COVID-19 cases until Tues. March 6, because of the Easter weekend.