New Brunswick recorded an estimated 423 deaths more than normal during an eight-week outbreak of the COVID-19 delta variant last fall, prompting questions about whether pandemic-related fatalities are being significantly underreported by the province's health officials.
Tara Moriarty says the answer is yes.
"Most Canadian provinces missed or don't report at least half of [COVID deaths] historically, and New Brunswick is included in that," said Moriarty, who is an associate professor and infectious disease researcher at the University of Toronto.
Late last summer, after mask requirements were dropped in late July just as COVID-19's delta variant was circulating in the province, New Brunswick was hit with its largest outbreak of infections to that point.
In the eight weeks spanning early September to late October, the province registered 3,615 new COVID-19 cases and 70 deaths.
But new figures released by Statistics Canada last week as part of its ongoing "excess mortality" study of the pandemic show a record 1,583 people died in New Brunswick during that eight-week period.
That is 423 more than would have been "expected" in the absence of the pandemic, according to the agency.
Included in that group are 218 people under the age of 45 who died during the eight-week period, 171 more than normal.
"To understand the direct and indirect consequences of the pandemic, it is important to measure excess mortality, which occurs when there are more deaths than expected in a given period," Statistics Canada explains in material attached to the death counts.
"There is evidence of excess mortality when weekly deaths are consistently higher than the expected number, but especially when they exceed the range of what is expected over several consecutive weeks."
The most deaths New Brunswick has ever recorded in the months of September and October in any year is 1,282. That was in 2019, but includes 61 days.
Eight weeks cover only 56 days, which is why the 1,583 deaths documented by Statistics Canada were calculated to be 423 above normal for that time of year.
Moriarty is the lead author of a study on COVID-19 mortality in Canada published last year. In an interview this week she said it is not statistically plausible for New Brunswick to have suffered only 70 COVID deaths in September and October if total deaths in the province were more than 400 above normal numbers.
She cites inadequate testing for COVID in New Brunswick, which ranked lowest among provinces throughout the pandemic, for likely missing dozens of COVID infections and deaths.
"New Brunswick really does under-test a lot for the size of its epidemic compared to the Canadian average, so New Brunswick, simply by the scale of testing that it does, likely misses at least half of its COVID deaths," said Moriarty.
Other provinces have had significant "excess" mortality counts as well, but few have had such large gaps between those and official provincial COVID death counts.
According to Statistics Canada, Saskatchewan was found to have had 406 more deaths than normal during same eight-week September-to-October period in which New Brunswick had 423, but it originally reported 240 COVID deaths to New Brunswick's 70.
Statistics Canada notes some of the upswing in deaths caused by COVID but not counted by provinces can be caused indirectly by issues like "delayed medical procedures" or "increased substance use."
Many COVID deaths go unrecognized: Moriarty
But Moriarty said her research shows that in most cases, COVID deaths go unrecognized, particularly in those who are never tested.
"Many people do die at home and because people who die are more likely to have, for example, diabetes or kidney disease or some other underlying feature, it's also quite common for it to be assumed that the death was due to those factors and not necessarily to COVID," she said.
"It's very complicated. Some of it is COVID that's simply not recognized, but a lot of it is COVID where it looks and smells like COVID, and it probably is COVID, but the postmortem testing is never done."
CBC News asked New Brunswick's Department of Health to provide any information that supports or disputes the claim that 423 more people than normal died in the province last September and October. The request was acknowledged but there has yet to be a response.
However, Statistics Canada says its "death counts" come from "provincial and territorial vital statistics registries."
New Brunswick initially led the country in reduced mortality during the pandemic, reporting 452 fewer deaths in 2020 than normal.
That changed in 2021. Beginning in September, New Brunswick's weekly excess death counts were, for its population, the highest among provinces.
No data past October has been posted yet for New Brunswick.