Global excess tuberculosis mortality during COVID-19: a country-level modeling study of policy and development correlates.

BACKGROUND: The COVID-19 pandemic disrupted global tuberculosis (TB) control efforts, leading to a surge in TB-related excess mortality, particularly in low- and middle-income countries. Pandemic mitigation measures, such as lockdowns, reallocation of healthcare resources, and reduced access to diagnosis and treatment, contributed to delayed TB care and disease progression. Quantifying this collateral damage is crucial to bolstering health system resilience. METHODS: We estimated country-level excess TB mortality between 2020 and 2023 using annual TB mortality data reported by the World Health Organization (WHO). Our approach leverages the SubEpiPredict toolbox of the ensemble n-sub-epidemic modeling framework, calibrated to pre-pandemic trends (2010-2019) to forecast expected TB deaths in the absence of COVID-19 disruptions. We selected the best-fitting model based on AICc and compared projected and reported deaths to quantify excess mortality, incorporating both normal and Poisson error structures. We further examined associations between excess TB mortality and country-level indicators, including the COVID-19 Stringency Index, Global Health Security (GHS) Index, and Socio-demographic Index (SDI). It is also noteworthy that for each estimate of excess TB deaths, we provide an associated uncertainty. RESULTS: Our global estimate of 755,876 excess TB deaths (95%CI: 591,099 to 965,015) aligns closely with the WHO estimate of approximately 700,000 excess deaths. Therefore, it can be estimated a global relative excess mortality of 12.8% (95%CI: 11.6% to 14.2%), compared to the WHO estimate of 14.6% (95% CI: 5.9% to 26.7%). We found substantial geographic heterogeneity, with the highest TB excess mortality rates observed in southern Africa, South Asia, and parts of South America. Countries with high GHS or SDI scores did not necessarily exhibit lower excess TB mortality, suggesting that pandemic-specific disruptions and competing priorities may have overridden structural advantages. Weak-to-moderate correlations were observed between excess mortality and pandemic stringency, peaking in 2021 and waning by 2022, possibly reflecting health system adaptation. CONCLUSION: This study presents a systematic, model-based analysis of global excess TB mortality during the COVID-19 pandemic, emphasizing disparities in pandemic response impacts across countries. The findings highlight the need for integrated and resilient public health systems capable of maintaining essential services amid global crises. Our methodology can support real-time monitoring of collateral effects of pandemics on endemic diseases and guide strategic investments in TB surveillance and care continuity.