COVID-19 daily death rates in U.S. and Canada begin to converge

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At the start of April, the gap between daily COVID-19 death rates in Canada and the U.S. was stark. By some tallies, Americans – after adjusting for population – were dying at a rate more than 500 per cent that of their neighbours to the north.

But that gulf has steadily narrowed over the past six weeks, and the difference in daily death rates is now less than 20 per cent.

Doctors and public-health experts cite three explanations for the trend. For one, New York, the outbreak’s epicentre in the U.S., has contributed significantly to the country’s overall death rate, and there is not a Canadian equivalent. Largely because of this, the U.S. suffered a much steeper pandemic curve, with a swift rise and marked fall, while Canada has had a slower and steadier progression. And there is evidence that under-counting of COVID-19-related deaths has been more severe in the U.S. than in Canada.

While the cumulative deaths per million in the U.S. over the course of the pandemic is still nearly double Canada’s, that gap is gradually eroding as daily death rates steadily converge.

Data from the European Centre for Disease Prevention and Control show a clear trend: Daily U.S. deaths per million were between five and six times higher than Canada’s during the first days of April; three times higher by the middle of the month; about a third higher at the start of May; and just 14-per-cent higher by this week.

Much of the U.S. curve is influenced by New York. The state’s 27,000 deaths account for roughly a third of the country’s total. And the pandemic’s rapid rise and eventual fall there largely account for the spike in the U.S. daily death rate and subsequent decline.

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Nowhere in Canada comes close. New York state has a per capita death rate nearly four times as high as Quebec, Canada’s worst-hit province. And New York City is more than twice as dense as Toronto or Montreal, Canada’s two most populous cities, one likely factor in the spread of the infection.

“Early on, the trajectory of the U.S., if you compare to anywhere else, was distorted by the fact that New York was different than other places,” said Dr. Prabhat Jha, an epidemiologist at St. Michael’s Hospital in Toronto. “Subsequently other places, seeing the fire in New York, have tried to do things differently, so subsequently the rates have been lower.”

This dramatic curve in the U.S. helps explain both the initial gap with Canada’s death rate, and its eventual narrowing. While the U.S.’s daily death rate careened up and then down, Canada’s increased more slowly and has begun to level off.

Other major U.S. cities severely affected by the pandemic, such as Detroit and New Orleans, also saw abrupt peaks and valleys in their death rates, which have contributed to the U.S.’s overall trajectory.

“The point of social distancing was to flatten the curve. And when you look at the curve for the U.S., there’s a sharp rise and then a plateauing. Canada is a much more gradual rise and then a plateauing,” said Dr. Leana Wen, a public-health expert at George Washington University. “What it says to me is that Canada is actually doing a good job. You’re not overloading the health care system.”

It is currently unclear how reliable the data are. Countries, states and provinces all tally COVID-19 deaths differently, and officials in the U.S. have said the country has probably under-counted its total deaths.

Calculations by the U.S. Centers for Disease Control and Prevention this week estimated that New York City’s coronavirus death toll between March 11 and May 2 could be more than 24,000, significantly higher than the official tally of 18,879. Among other things, the higher total could account for people who died at home or were never tested for coronavirus.

Jay Kaufman, an epidemiologist at McGill University, suspects that any under-counting in Canada is not as dramatic as in the U.S. For instance, the U.S. has recorded a much lower proportion of coronavirus-related deaths in nursing homes than Canada, which could suggest American facilities aren’t reporting deaths as thoroughly as their Canadian counterparts.

Prof. Kaufman also says he is “suspicious” of relatively low infection rates in populous states such as Texas, Florida and Georgia.

Neither country has so far released a complete estimate of uncounted COVID-19 deaths.

“The numbers are not so easy to compare, because the conventions for declaring a death to be assigned as a COVID-19-attributable death differ by country,” he wrote in an e-mail. “Once we know the correct counts, I expect the U.S. to remain above Canada, but since Canada has successfully spread out infections over time, it may continue to rise for some time.”

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