Is Excess Mortality Returning to Pre-Pandemic Levels? A Multi-Model Stochastic Approach for COVID-19: The Spanish Case.

Abstract

Introduction: This study quantifies excess mortality in Spain during and after the COVID-19 pandemic and assesses whether mortality levels are returning to pre-pandemic patterns.

Methods: Expected mortality was estimated using stochastic forecasting models calibrated on pre-pandemic data (1990-2019) and compared with observed mortality over the period 2020-2023. The analysis relies on a multi-model framework including the Lee-Carter, Cairns-Blake-Dowd, and age-period-cohort models.

Results: The results show a substantial excess mortality during the pandemic years, with the proportion of ages exhibiting punctual excess mortality increasing from around 65% before the pandemic to approximately 85% during 2020-2022. Excess mortality declined sharply in 2023, when indicators returned to levels comparable to those observed prior to COVID-19, suggesting a transition toward near-normal mortality. The Lee-Carter model showed superior short-term performance in detecting abrupt mortality deviations, while APC and CBD models captured longer-term structural patterns.

Conclusions: These findings highlight the usefulness of multi-model stochastic approaches for monitoring excess mortality and assessing recovery trajectories following major epidemiological shocks.