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Long-Term Impacts of Exposure to the COVID-19 Pandemic in a Cohort Perspective

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August 2025

Authors

Eugenio Paglino, PhD
University of Pennsylvania, Population Studies Center

Andrew C. Stokes, PhD
Boston University, School of Public Health

Executive Summary

This report presents findings from a project investigating the long-term impacts of the COVID-19 pandemic on mortality. The project had three objectives: 1) estimating the reduction in life expectancy experienced by birth cohorts affected by the pandemic, 2) understanding how future life expectancy will change under different mortality scenarios after the acute phase of the pandemic, and 3) investigating whether excess mortality at one age is associated with excess mortality at subsequent ages across cohorts. The study is based on cohort mortality data from the Human Mortality Database for 1985-2023. Cohort-specific excess mortality rates and ratios were computed by comparing observed death rates to deaths expected based on pre-pandemic mortality trajectories. The gap between observed and expected mortality was investigated under four different scenarios representing different paces of return to pre-pandemic trends. Finally, the correlation between cohort-specific excess mortality in 2020-2021 and 2021-2022 was assessed, revealing important insights into the presence of mortality selection, acquired immunity, and scarring effects.

The main findings of the study are summarized below:

  • Every cohort included in the study displayed higher-than-expected mortality in 2020-2023 compared with expected trends based on ten years of pre-pandemic data.
  • Excess cohort mortality was higher at ages affected by 2020-2021 mortality than at ages affected by 2021-2022 and shows further declines at ages affected by 2022-2023 mortality. Despite declines in excess mortality, mortality at all ages affected by the pandemic was above the expected level.
  • Even if mortality were to immediately return to pre-pandemic trends, losses of life that have already occurred imply that declines in the probability of reaching age 95 for females will range from 1.4% to 11.7%, with an average decline of 4.8%. Among males, the declines will range from 1.7% to 12.3%, with an average decline of 5.2%.
  • A permanent deviation of mortality from pre-pandemic trends – i.e., no return to the pre-pandemic mortality trend – would imply an average decline of 10.8% in the probability of reaching age 95 for both females and males.
  • These reductions in expected longevity translate into 206,253 additional female deaths before age 95 under the best-case scenario, which grow more than two-fold to 505,208 under the worst-case scenario.
  • The corresponding figures for males are 113,083 additional deaths under the best-case scenario, which more than doubles to 259,840 under the worst-case scenario.
  • Comparing excess mortality rates between 2020-2021 and 2021-2022, the level of excess mortality in 2020-2021 predicts almost perfectly the level in 2021-2022, suggesting that common factors such as the prevalence of pre-existing conditions or comorbidities and socioeconomic status (correlated environments) explain variation in excess mortality across cohorts in both periods.
  • Conversely, the lack of a relationship between the level of excess mortality in 2020-2021 and changes in excess mortality between 2020-2021 and 2021-2022, suggest that high excess mortality at a given age was not systematically associated with lower-than-average –– as positive selection of survivors and acquired immunity would imply –– or higher-than-average –– as scarring would imply –– excess mortality at subsequent ages. These findings are consistent either with the absence of acquired immunity, selection, and scarring effects or with effects of opposite sign (e.g. acquired immunity and scarring) offsetting each other.

Material

Long-Term Impacts of Exposure to the COVID-19 Pandemic

Acknowledgements

The authors’ deepest gratitude goes to those without whose efforts this project could not have come to fruition: the volunteers who generously shared their wisdom, insights, advice, guidance, and arm’s-length review of this study prior to publication. Any opinions expressed may not reflect their opinions nor those of their employers. Any errors belong to the authors alone.

Project Oversight Group members:

Jean-Marc Fix, Chair, FSA, MAAA

Samuel Behrend, FSA, MAAA

Benjamin Blakeslee, FSA, MAAA

Carolyn Covington, FSA, MAAA, CERA

Jonathan Crawford, ACIA

Mark Evans, FSA, MAAA

Joel Jones

Yutaro Kameda, FSA

Andrea Melink, FSA

Marianne Purushotham, FSA, MAAA

Rebecca Reppert, FSA, MAAA, CERA

David Stoddard, FSA, MAAA

Qi Yao, FSA, FCIA

At the Society of Actuaries Research Institute:

Kara Clark, FSA, MAAA, Senior Research Actuary

Barbara Scott, Senior Research Administrator

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