Variability in excess deaths across countries with different vulnerability during 2020-2023

Abstract Excess deaths provide total impact estimates of major crises, such as the COVID-19 pandemic. We evaluated excess death’s trajectories during 2020-2023 across countries with accurate death registration and population age structure data; and assessed relationships with economic indicators of vulnerability. Using the Human Mortality Database on 34 countries, excess deaths were calculated for 2020-2023 (to week 29, 2023) using 2017-2019 as reference, with weekly expected death calculations and adjustment for 5 age strata. Countries were divided into less and more vulnerable; the latter had per capita nominal GDP<$30,000, Gini>0.35 for income inequality and/or at least 2.5% of their population living in poverty. Excess deaths (as proportion of expected deaths, p%) were inversely correlated with per capita GDP (r=-0.60), correlated with proportion living in poverty (r=0.66) and modestly correlated with income inequality (r=0.45). Incidence rate ratio for deaths was 1.06 (95% confidence interval, 1.04-1.08) in the more versus less vulnerable countries. Excess deaths started deviating in the two groups after the first wave. Between-country heterogeneity diminished over time within each of the two groups. Less vulnerable countries had mean p%=-0.8% and 0.4% in 0-64 and >65 year-old strata while more vulnerable countries had mean p%=7.0% and 7.2%, respectively. Usually lower death rates were seen in children 0-14 years old during 2020-2023 versus pre-pandemic years. While the pandemic hit some countries earlier than others, country vulnerability dominated eventually the cumulative impact. Half of the analyzed countries witnessed no substantial excess deaths versus pre-pandemic levels, while the other half suffered major death tolls. Significance Statement Excess deaths during 2020-2023 reflect the direct and indirect effects of the COVID-19 pandemic and of the measures taken. Data from 34 countries with detailed death registration and allowing to adjust for changes in the age structure of the population over time show two groups, each with very different excess death outcomes. The 17 more vulnerable countries (those with per capita nominal GDP<$30,000, Gini>0.35 for income inequality and/or at least 2.5% of their population living in poverty) had very high excess deaths compared with 2017-2019, while the other 17 less vulnerable countries had deaths during 2020-2023 that were comparable to 2017-2019. Continuous monitoring of excess deaths helps understand how country vulnerability shapes long-term impacts.