The number of Canadians who have died because of the COVID-19 pandemic is now over 1,200 — more than double the lower estimates in federal projections published last week.

The surge in deaths is due to unexpected outbreaks of the disease in long-term care facilities, Prime Minister Justin Trudeau said today.

Dr. Theresa Tam, Canada's chief public health officer, released the federal government's COVID-19 modelling on Apr. 9 . The projections included a number of scenarios and long-term forecasts, including a death toll of between 11,000 and 22,000 over the course of the pandemic — even with the maintenance of physical distancing and other disease control measures.

The projections also included a shorter-term forecast, projecting between 22,580 and 31,850 reported cases and between 500 and 700 deaths in Canada by Apr. 16.

While the number of reported cases — 29,826, according to Thursday's count by the federal government — is within that range, the number of deaths is significantly higher. According to a count by CBC News, Canada has 1,240 reported pandemic deaths as of this afternoon.

Households show their support by posting signs for Almonte Country Haven long-term care home during the COVID-19 pandemic in Almonte, Ontario on Monday, April 13, 2020. The 82-bed home reported 14 deaths due to COVID-19 and 36 residents have tested positive for the virus. (Sean Kilpatrick/The Canadian Press)

This means the current count is at least double the lower end of the federal projected count for Apr. 16. As more deaths are reported and counted over the next day, the toll could double even the higher estimates.

There is significant uncertainty in disease models that have to rely on inconsistent and incomplete sources of data . COVID-19 is also a new disease, which means it's not entirely understood.

Trudeau defended the modelling at his daily press conference today, saying it provides a framework for planning. But he also said that the situation in long-term care facilities is more dire than expected.

"I think one of the things we've seen over the past number of weeks," he said, "is a far more severe impact on seniors' residences and long-term care facilities than we had certainly hoped for, or more than we feared."

WATCH | Concerns over gaps in Ontario's plans for COVID-19 crisis in long-term care homes:

Concerns are being raised about gaps in the Ontario government’s plan to address the COVID-19 crisis in long-term care homes including not preventing staff from working in multiple facilities. 2:05

According to Dr. Tam, nearly half of all deaths have been linked to long-term care homes. Both Ontario and Quebec are grappling with outbreaks in these facilities.

On Wednesday, Quebec Premier François Legault said these homes were down 2,000 workers and he called on everyone with health care experience — including specialists — to help fill those gaps .

Government projects up to 1,620 total deaths by Tuesday

Asked on Thursday to explain the differences between the projected and actual death tolls, Dr. Tam pointed to two factors.

The unexpectedly high proportion of cases in long-term care facilities — where those infected are particularly vulnerable — has increased the fatality rate, she said. She also said that the case fatality rate earlier in an epidemic can be under-estimated because of the time it takes for people to either recover or die from the illness.

Dr. Tam said she expects the case fatality rate to increase as the growth rate of infections continues to decrease.

Asked what this tells us about where Canada is on the projected curve, Dr. Tam said that "short-term forecasts are very sensitive to our actions but also to the epidemiology, and that projection has to change really very quickly on a daily basis."

According to the latest models from the Public Health Agency of Canada, the federal government is now projecting between 1,200 and 1,620 pandemic deaths by Apr. 21.

The country already has passed the lower end of that range, but Dr. Tam said the numbers will continue to evolve.

"Any number that I provide you will be subjected to variations as we change those projections over time."