Excess Mortality and Containment Performance During the COVID-19 Pandemic: Evidence From 34 Countries.

To expand COVID-19 containment indicators to evaluate the relationship between excess mortality and government response. We developed a longitudinal study analyzing excess mortality, COVID-19 containment, and structural conditions in 34 countries between 2020 and 2022. The average excess mortality ratios of the 34 countries were 1.09, 1.14, and 1.11 in 2020, 2021, and 2022, respectively. Thirteen countries experienced continuous annual rises, while only 2 had consistent annual declines. Top-performing countries significantly reduced excess deaths by 5.7% (b = -0.06; 95% CI [confidence interval] = -0.10, -0.01;  = .02) in 2020 and 12.9% (b = -0.13; 95% CI = -0.17, -0.08;  < .001) in 2021, compared to bottom performers. Middle-performing countries saw reductions of 6.7% (b = -0.07; 95% CI = -0.11, -0.02;  = .01) and 10.6% (b = -0.11; 95% CI = -0.15, -0.06;  < .001). These findings suggest that better containment is associated with fewer excess deaths, even after accounting for preexisting structural differences. The COVID-19 containment indicators' precision emphasizes the association between better containment and lower excess mortality during early and postvaccine development periods. Our findings urge governments to utilize new metrics that balance flexibility and strictness for pandemic strategies, informing future policy interventions. (. 2025;115(9):1518-1528. https://doi.org/10.2105/AJPH.2025.308136).