COVID-19 death toll in Canada may be higher than official numbers indicate: analysis
The COVID-19 death toll during the first nine months of the pandemic may be higher than the provinces’ official numbers, according to an analysis of new national data by a Toronto researcher.
Tara Moriarty, a professor of laboratory medicine and pathobiology at the University of Toronto, examined national mortality data compiled from Statistics Canada from March to November 2020.
She found that the rate of “excess deaths” – which occurs when there are more deaths during a period of time than what would be expected for that period – was much higher than the COVID-19 death tolls reported by the provinces.
“Baseline/expected deaths include deaths due to all the "normal" causes of death. The excess death is on top of that and is due to something new,” Moriarty explained on Twitter.
Moriarty suggested that it’s likely some provinces inadvertently missed some COVID-19 cases and deaths in their official tallies during this period.
In her analysis, Moriarty removed toxic drug deaths to ensure the excess deaths weren’t attributable to Canada’s ongoing opioid epidemic.
Even controlling for toxic drug deaths, the researcher found that Canada had more than 3,000 excess deaths during the first nine months of the pandemic that weren’t attributed to COVID-19.
Interestingly, Moriarty found the greatest disparity between provincial COVID-19 death tallies and excess death rates was in Western Canada, where the provinces reported fewer deaths from COVID-19 than in Ontario and Quebec during the beginning of the pandemic.
“This likely means that there have been more deaths [from COVID-19] than we know about,” Moriarty told CTV’s Your Morning on Tuesday.
In British Columbia, for example, Moriarty found there were 1,650 excess deaths – compared to 290 official COVID-19 deaths. In people over the age of 64, who are the most vulnerable to COVID-19, the analysis found there were 1,099 excess deaths.
“It could be that a lot of cases in B.C. were in northern and Northwestern B.C.,” Moriarty said. “There may not have been the testing capacity that was needed in that region. This is likely true in a number of northern parts of the country as well and it means that we likely missed a lot of cases and deaths.”
Mar-Nov 14, 2020#COVID19 #Canada
Estimated excess deaths/100K in different age groups (all, 45+, 65+) compared to reported C19 deaths and C19 deaths estimated from seroprevalence data and current case fatality rates
Estimated excess deaths are adjusted for toxic drug deaths. pic.twitter.com/dFQ72wmeBB
Alberta had 1,049 excess deaths compared to 401 deaths related to COVID-19, while Saskatchewan had 209 excess deaths and 29 reported COVID-19 deaths.
Ontario had 4,037 excess deaths versus 3,372 COVID-19 deaths during the studied period.
Quebec was the only anomaly in Moriarty’s analysis with more COVID-19 deaths reported than excess deaths, which she said may be because the province includes probable COVID-19 deaths in their official tallies while others do not.
The analysis found almost no difference in excess deaths and official COVID-19 deaths in Atlantic Canada and the North.
FINDING A CAUSE
Moriarty said there could be several reasons why there was a high number of excess deaths in certain provinces during the first nine months of the pandemic.
Firstly, she said there could have been a lot of people who died from the virus at home, instead of in a long-term care homes or hospitals where officials were keeping closer tabs on the disease.
“We’re very aware of deaths in long-term care, but we may have missed a lot of deaths among seniors living in their own homes who never made it to hospital and weren’t in long-term care,” she said.
Moriarty further explained that COVID-19 presents differently in older patients because they have weaker immune systems that are unable to mount a robust defence against the virus. She said this means those seniors who died in their homes may not have exhibited typical symptoms of the disease and were, therefore, not counted as COVID-19 cases when they died.
The medical researcher also said another important factor is that provinces differ in their reporting criteria and how they classify deaths from COVID-19.
“One of the things that’s important to know is that a number of provinces, including Ontario and Saskatchewan at this point, don’t report the probable cases of COVID-19 and the probable COVID-19 deaths,” she explained.
“They don't officially report these even though Health Canada and World Health Organization guidance is that they should be reporting them.”
In an email to CTVNews.ca on Tuesday, a spokesperson for the Saskatchewan Ministry of Health said the province considers a death to be a “COVID-19 death” when the death is “a result of a clinically-compatible illness in a COVID-19 case, unless there is a clear and immediate alternative cause of death that cannot be related to COVID-19 (e.g., trauma).”
The spokesperson added that COVID-19 death reporting is done under “urgent timelines” to keep Saskatchewan residents informed on the status of the disease as soon as possible.
“Not all COVID-19 deaths will be reported to public health for a variety of reasons, for example, not all people infected with COVID-19 are tested due to a variety of reasons, the death was due to symptoms not typically associated with COVID-19 symptoms, etc.,” the statement said.
Tom McMillan, assistant director of communications for Alberta Health, said in an emailed statement that COVID-19 accounts for about 1,200 deaths, and opioid and other drug overdoses increased by about 500 from the prior year. He said the remainder, around 400-500 deaths, is within the range of year-to-year variation in total deaths in recent years.
“Work is underway to investigate potential causes of these excess deaths. The number, apart from COVID-19 and opioid-related fatalities, is too small to support the attribution of specific causes without further in-depth analysis,” he wrote.
“It is possible that some COVID-19 deaths have been missed or under-counted, but unlikely on any large scale given the attention to COVID beginning well before our first death was reported.”
McMillan also said it’s possible, as other jurisdictions have suggested, that some of the deaths were due to a disruption of patients’ normal decisions to seek care.
He added that Alberta reports “all deaths that are deemed to have COVID-19 as the cause of death or as a contributing factor. This includes any death resulting from a clinically compatible illness, in a probable or confirmed COVID-19 case, unless there is a clear alternative cause of death identified (e.g., trauma, poisoning, drug overdose).”
CTVNews.ca has also reached out to B.C., Manitoba, Ontario, and Quebec for comment on their COVID-19 death reporting.
Moriarty said she hopes the takeaway from her analysis is that provinces should be following Health Canada and the World Health Organization’s guidance on COVID-19 reporting.
Additionally, she said that Canadians should expect more deaths from COVID-19 in people’s homes, rather than in long-term care facilities, during the third wave of the pandemic.
“I think that we're going to be surprised now that there will continue to be quite a bit more deaths across the country, but it will be occurring out in communities,” she said.
“So it’s very important for people to know is that elderly people, older people, often have atypical presentations of COVID-19.”