Excess Mortality Estimation During the COVID-19 Pandemic: Preliminary Data from Portugal

Introduction: Portugal is experiencing the effects of the COVID-19 pandemic since March 2020. All-causes mortality in Portugal increased during March and April 2020 compared to previous years, but this increase is not explained by COVID-19 reported deaths. The aim of this study was to analyze and consider other criteria for estimating excessive all-causes mortality during the early COVID-19 pandemic period. Material and Methods: Public data was used to estimate excess mortality by age and region between March 1 and April 22, proposing baselines adjusted for the lockdown period. Results: Despite the inherent uncertainty, it is safe to assume an observed excess mortality of 2400 to 4000 deaths. Excess mortality was associated with older age groups (over age 65). Discussion: The data suggests a ternary explanation for early excess mortality: COVID-19, non-identified COVID-19 and decrease in access to healthcare. The estimates have implications in terms of communication of non-pharmaceutical actions, for research, and to healthcare professionals. Conclusion: The excess mortality occurred between March 1 and April 22 was 3.5- to 5-fold higher than what can be explained by the official COVID-19 deaths.