TORONTO -- How many people died of COVID-19 in Canada last year?

It's not as simple a question as it may seem.

Officially, if you tally up every death announced by every province and territory, there were 15,606 people killed by the novel coronavirus in this country in 2020 – equivalent to nearly twice the population of Banff, Alta.

That number would have represented Canada's third-leading cause of death in any year since the turn of the century, according to Statistics Canada data.

Cancer and heart disease are consistently Canada's top two killers. In 2019, they accounted for 80,152 and 52,541 deaths, respectively. The next three leading causes of death are accidents and unintentional injuries, cerebrovascular diseases, and chronic lower respiratory diseases. Each of these typically accounts for more than 10,000 deaths a year in Canada, but none has topped 15,000 since 2003.

"[COVID-19] could conceivably have been No. 1, and been way ahead of heart disease and cancer, if we had not done what we have done – and had better continue to do," Heather MacDougall, a University of Waterloo professor who specializes in the history of medicine and public health, told CTVNews.ca via telephone on Tuesday.

"All of these deaths are tragic, but realistically it could be a whole lot worse. That seems to be a point that isn't really getting out there."

COVID-19 was not necessarily the primary cause of every single one of those 15,606 deaths; some of the patients may have died of something else after contracting COVID-19. On the other hand, that total does not include patients who died of COVID-19 without ever realizing they had it or being tested for it – something that was much more likely to happen in the early days of the pandemic. There's also the question of indirect deaths – those who died by suicide because of depression worsened by lockdowns, or those who died of natural causes because they were unwilling to seek hospital treatment.

In other words, 15,606 is most likely not the exact number of deaths from COVID-19 in Canada in 2020. However, experts who spoke with CTVNews.ca say it's a reasonable early estimate.

COVID-19 VS. THE 1918-20 FLU PANDEMIC

Estimates are often as good as it gets for pandemic death tolls. Nobody knows exactly how many Canadians died due to the influenza pandemic that devastated the world between 1918 and 1920. The federal government's own webpage on the topic says "approximately 55,000 people in Canada" were killed, and no other official sources attempt a more exact count.

"It's always putting together a puzzle," Esyllt Jones, a professor at the University of Manitoba who specializes in the history of medicine, told CTVNews.ca on Tuesday via telephone.

Attempting to piece together that puzzle now, 100 years later, involves combing through sources, such as church records or even individual death certificates – some of which may still be considered protected information.

Even where the records are available and accessible, though, there may be questions about their reliability. There was no lab test to confirm influenza presence in a body 100 years ago, the way there is for COVID-19 today, and flu-like symptoms can indicate plenty of other infections.

"You have to be cautious in interpreting them, because death certificates are not always completely accurate indications of the cause of death," Jones said.

"People are doing their best, but it's not foolproof – and when you have a pandemic and you have hundreds of people dying a day, those processes also tend to break down a bit."

MacDougall said that in the Ontario of 100 years ago, local public health authorities – which led efforts to control the pandemic – often had to rely on funeral directors to let them know about deaths. Sometimes, there could be a backlog of several months between a death occurring and it being officially recorded.

"There's only 24 hours in every day – and if your community is in the midst of an actual outbreak … they are busy making coffins or trying to get people buried. I can see that the paperwork was not a priority at the time," she said.

Inaccurate, incomplete and slow data remains a concern today. Former federal health minister Jane Philpott told CTV News Channel last month that the release of data related to deaths in Canada tends to lag behind the deaths themselves by about two years, making it difficult for governments to spot and address emerging trends in a timely manner.

OTHER PANDEMICS AND WARS

The full extent of death in Canada caused by the 1918-20 flu pandemic may never be known at all, but Jones said it's clearly greater than that of COVID-19 thus far.

"The flu pandemic had very high mortality – over six per 1,000 population," she said.

"So far, our [COVID-19] death rates are not that high – of course, they are higher than any other infectious disease outbreak that we've had."

Indeed, a search through the annals of recorded Canadian history yields few other events with death tolls even remotely comparable to the current pandemic.

COVID-19 has already proven deadlier to Canada than other major flu pandemics of the 19th and 20th centuries, some of which killed a few thousand people apiece here.

"COVID is far more publicly recognized, largely because it is a new disease – it is a second novel coronavirus – whereas the flu in 1957-58 and the one again in 1968-69, it was identified as flu," MacDougall.

The two world wars both claimed a similar number of Canadian lives to the 1918-20 flu, with nearly 67,000 deaths attributed to the First World War and more than 45,000 to the Second World War. An estimated 10,000 British troops and 10,000 Indigenous allies were killed during the War of 1812.

Nearly 25,000 people in Canada have died from HIV/AIDS over the past four years, according to advocacy group CATIE, and it is estimated that more than 20,000 were killed in a typhus epidemic in 1847. While Canada has not hit either of these numbers yet, another year similar to 2020 would put us past both.

What seems extremely unlikely, though, is that COVID-19 will kill people here at a similar rate to the deadliest event (per capita) in Canadian history: the first contact between Indigenous Peoples and European settlers.

While data on the death toll from smallpox and other infections introduced to these populations is very difficult to come by, the First Nations Health Authority says it is estimated that Indigenous populations shrunk by between 50 and 90 per cent after European contact – and recent research suggests the true number is likely on the higher end of that range.