Vaccination Intensity and Mortality During the COVID-19 Pandemic: A Cross-National Panel Analysis with Lagged and Time-Varying Associations

This study examines population-level associations between COVID-19 vaccination intensity and mortality using a cross-national weekly panel of 89 countries from March 2020 to July 2023. Weekly all-cause mortality and non-COVID-19 mortality are modeled as functions of vaccination intensity using distributed lags and placebo leads to distinguish delayed associations from reactive rollout dynamics. The analysis accounts for serial correlation, seasonality, epidemic conditions, non-pharmaceutical interventions, viral variants, weather, and unobserved country-level heterogeneity. Across specifications, vaccination intensity shows no positive association with non-COVID-19 mortality at any post-vaccination horizon. For all-cause mortality, results are consistent with a delayed negative association at medium-term lags, aligning with reductions in COVID-related deaths. Placebo leads indicate reactive vaccination rollout during periods of elevated mortality risk, underscoring the importance of explicit temporal diagnostics in aggregate analyses. This manuscript has not undergone peer review. The findings represent population-level associations derived from aggregate data and do not identify individual-level causal effects or rare adverse events. All data sources and replication code are publicly available via linked repositories.