Virus waning, but relaxation of curbs risky, Tam warns

• 90% of new cases in Ontario, Quebec • 80% of deaths linked to care homes

OTTAWA — Canada’s top doctor says the country has been successful at slowing the spread of COVID-19, but warns that relaxing public-health restrictions too quickly or too soon could lead to a rampant resurgence of the disease.

Dr. Theresa Tam presented a new report on the novel coronavirus in Canada on Thursday, including new short-term projections that say between 157 and 1,857 more Canadians could die of COVID-19 in the next 11 days.

The projections, based on recent trends, estimate in the best-case scenario at least another 4,459 people will be diagnosed with COVID-19 by June 15, and in the worst-case scenario there will be more than 14,000 new cases by then. What happens depends almost entirely on how well Canadians practise proper public-health behaviours, and how good health systems are at testing, contact-tracing and isolating positive cases.

“Without a vaccine or treatment, public-health measures remain essential to control the epidemic,” said Tam.

Canada has been averaging just under 800 new cases a day for the past week, down from an average of 1,050 new cases the week before that.

Tam said most of the country has seen spread of the disease diminish substantially, but there remain hot spots of community transmission in Toronto and Montreal that are concerning.

In the past two weeks, Ontario and Quebec accounted for 90% of new cases, and most of those were in those two cities.

Tam said the efforts Canada has made, including physical distancing and closures of businesses and public spaces, have allowed us to flatten the curve, but we can’t get cocky and think the worst is over so we can get back to normal now.

As of Thursday, Tam said, Canada has had 93,441 positive cases and 7,543 deaths. She said about 16% of patients required hospitalization and 3% needed to be admitted to intensive care.

The 8% death rate reflects the number of outbreaks in long-termcare homes — more than 80% of patients who died are connected to long- term care homes or seniors’ residences.

But Tam said the rate must be viewed knowing the overall number of people who have had COVID-19 is not known, because lab-confirmed cases are “just the tip of the iceberg.”

Plans to test Canadians for antibodies to detect whether they have had the novel coronavirus will give a better sense of the true number of cases, Tam said.

The report says with a high degree of physical-distancing and case-testing and tracing, Canadians can expect that the number of new cases will stay very low, including no real second wave in the fall. With weaker controls, a surge of cases could see half of Canadians infected, with a rising number of cases throughout the summer and into next winter. With no controls, as many as 80% of Canadians will get infected by the end of the summer.