The COVID‑19 pandemic had a tremendous impact on many facets of human life. Although it affected countries around the world, these impacts can be difficult to compare since the data available differs from country to country. One way to assess the data is by considering excess mortality.
Excess mortality, or excess deaths, is the number of deaths exceeding expected levels in a specific period. Excess mortality provides valuable insight into the broader impact of the Covid pandemic because it captures the direct impact of the virus on deaths, as well as potential indirect impacts, such as overwhelmed healthcare systems, delayed medical treatments, and other effects. Excess mortality also captures any effects that may reduce mortality, such as reduced deaths associated with motor vehicle accidents during periods where stay-at-home orders were in place or reduced deaths due to decreased circulation of influenza viruses. Finally, excess mortality includes Covid deaths that were not captured by official Covid death statistics.
In this article we focus on the impact of the Covid pandemic on mortality in Canada using the measure of excess mortality. More specifically, we look at excess mortality relative to the expected number of deaths within the general and insured populations of Canada, we identify areas for further monitoring, and we discuss potential causes of excess mortality for lives below age 45.
Population Excess Mortality
Statistics Canada introduced weekly excess death tracking as part of its Covid monitoring.1 Excess mortality for the Canadian population was recorded between January 2020 and August 2023, at which point, Statistics Canada stopped the official tracking.
Statistics Canada defined excess mortality as the difference between the number of observed deaths and the number of expected deaths over a certain period of time. This definition may have underestimated or overestimated excess mortality during the Covid pandemic because it is difficult to collect actual death counts across provinces and territories in a timely manner. As such, the actual deaths are based on provisional death counts, which were adjusted for reporting delays where possible. Additionally, this approach relies on developing an expected basis had there been no pandemic. Statistics Canada used recent trends to estimate expected deaths. We cannot know what mortality levels would have been had there been no pandemic, so the expected basis could also underestimate or overestimate excess mortality.2
Figure 1 – Excess mortality in Canada as a % of expected deaths (13‑week smoothing)