Coronavirus death graph shows how March’s lockdown saved lives: expert

Click to play video: 'B.C. health officials investigating excess deaths during pandemic'
B.C. health officials investigating excess deaths during pandemic
WATCH: British Columbia health officials investigating excess deaths – May 4, 2020

A steady flattening — and what may be early signs of a decrease — in Canada’s coronavirus deaths reflect the locking down of society starting in mid-March, an expert says.

“It’s good news — this is what we want to see,” says Steven Hoffman of York University. “A flattening first, and then a quick reduction.

“That being said, it highlights that we have challenges — there are still too many people dying every day of COVID-19.”

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The graph shows an upward trend until mid-April and then (clearly, in retrospect) a slowing and flattening pattern.

That reflects the shutdown and social-distancing measures that started in Canada about a month previously, in mid-March, he says: someone who dies of the novel coronavirus was likely infected three or four weeks previously.

“That’s when all the most significant public health measures were being implemented,” he says. “Every day, a new set of measures were coming into place across the country, and we were seeing robust efforts for physical distancing.

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“The timeline does match.”

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Coronavirus outbreak: South Korea authorities looking at mobile phone data, credit cards to trace possible COVID-19 infections

Official totals of coronavirus deaths may not capture all of them. Some people with pre-existing medical conditions may have their deaths accounted for with a different cause, for example.

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In many western countries, overall deaths have increased by much more than formal coronavirus death tolls can account for. There are a number of possible explanations: one is that people with unrelated health issues, such as heart attacks, may be avoiding hospitals.

The thin line above shows a rolling seven-day average of deaths. Looking at the data that way smooths out misleading highs and lows and lets us see something closer to the real trend.

“The rolling average allows people to more accurately see the information that’s informative,” he says.

“The day that would be most helpful is the day that someone got infected, and that information we never get because we don’t have the technology to know that.”

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A graph of deaths should be seen with an alternate reality in mind, Hoffman says: without lockdown measures, as painful as they were to many Canadians’ livelihoods, deaths would probably have spun upward exponentially starting in mid-April.

“Regularly in an outbreak, you’d expect an exponential increase in the number of cases and deaths,” he says.

Click to play video: 'Coronavirus outbreak: Man in his 50s first known death in Toronto‘s shelter system'
Coronavirus outbreak: Man in his 50s first known death in Toronto‘s shelter system

With the uncontrolled growth of cases, hospitals would be overwhelmed and more of those infected would die, Hoffman explains.

“With even greater exponential cases, you might even expect an increasing percentage of those cases facing severe consequences because health-care resources become more limited,” he says.

“The good news is that we haven’t seen that. The number of cases in Canada has never exceeded our health-care capacity to address cases.”


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