Importance The COVID-19 pandemic disrupted long-term mortality declines. Preliminary 2024 data indicate a return to prepandemic trends, but part of this reduction may reflect mortality displacement, in which frail or high-risk individuals died earlier than they otherwise would have during the pandemic, possibly leading to temporarily fewer deaths in subsequent years. Objective To estimate global all-cause mortality trends during and after COVID-19 and assess the association of mortality displacement with mortality declines seen in 2023 and 2024. Design, Setting, and Participants This retrospective cross-national, cross-sectional time-series study assessed mortality data from January 2015 to December 2024, with January 2015 to December 2019 serving as the prepandemic baseline for country-specific, age-adjusted linear projections of expected mortality. Countries were included with high-quality national mortality reporting from the Human Mortality Database Short-Term Mortality Fluctuations. Total populations for each country were stratified by sex and age (0-14 years, 15-64 years, 65-74 years, 75-84 years, and ≥85 years). Exposures The COVID-19 pandemic years (2020-2022 or 2020-2023) and postpandemic years (2023-2024 or 2024 alone), relative to a 2015-to-2019 prepandemic baseline. Main Outcomes and Measures Excess mortality is defined as actual minus expected mortality, in which expected deaths were projected from prepandemic (2015-2019) data using an overdispersed Poisson regression model. Mortality displacement was defined as a statistically significant postpandemic mortality deficit in 2023 and 2024 (or in 2024) following a positive excess mortality during the 2020-2022 (or 2020-2023) pandemic period. To quantify the magnitude of mortality displacement, the mortality displacement ratio was defined as the ratio of the cumulative postpandemic deficit to the cumulative pandemic-period excess. Results This study included 352 182 284 deaths across 34 countries from 2015 to 2024, with a median (IQR) 2020 population composition of 50.75% (50.33%-51.44%) female and 19.64% (17.74%-20.64%) aged 65 years or older. Statistically significant mortality displacement was detected in 3 of 34 countries (Greece: 10% 95% CI, 4%-15%, Latvia: 21% 95% CI, 14%-28%, and Poland: 21% 95% CI, 17%-25%), predominantly among adults aged 85 years or older and in strata in the highest quintile of COVID-19–era excess mortality. In 2024, the US returned to its prepandemic pattern of stable mortality, with an excess mortality rate of 3 (95% CI, −2 to 7) per 100 000. In contrast, most European countries had not yet resumed their prepandemic trajectories, exhibiting excess mortality rates ranging from 11 (95% CI, 3-18) per 100 000 in France to 115 (95% CI, 94-135) per 100 000 in Lithuania. Conclusions and Relevance In this cross-sectional study of 34 countries, postpandemic mortality declines were rarely associated with mortality displacement; most European countries had not returned to their prepandemic mortality trajectories by 2024. These results suggest that pandemic strategies should prioritize population-wide protection and highlight the need to understand why so many European countries have failed to resume their pre–COVID-19 pattern of mortality decline.
Chen et al. (Thu,) studied this question.