Ontario hastily reverses reopening as new variants usher in a third wave of Covid cases

Canada's most populous province has been warning of rapidly spreading coronavirus variants, as cases and ICU admissions surged

Lisa Salamon-Switzman, an emergency room doctor in Toronto, had already worked through two deadly surges of the coronavirus pandemic when a new batch of patients recently began arriving that left her unsettled because of their low oxygen levels - and their age.

They're younger than what we saw earlier and they don't really understand how sick they are," she said of patients who are in their 40s and 50s. And now it's become this huge, huge wave."