K. M. Al-Dhayani
Background: Meningitis remains a major cause of global morbidity and mortality. We aimed to quantify the association between vaccine introduction and meningitis-related disability-adjusted life year (DALY) rates globally and across high-burden regions from 2000 to 2023. Methods: We conducted a longitudinal panel study of 188 countries using health metrics from the Global Burden of Disease study and WHO vaccine data. We estimated associations using two-way fixed effects regression models, adjusting for GDP and healthcare access. Analyses were stratified by baseline burden and included the African meningitis belt. Findings: Globally, meningitis DALY rates declined by 4.97% per year (p<0.0001). Introduction of the Hib vaccine was associated with a 6.7% reduction in DALY rates, and PCV with a 4.8% reduction. In high-burden countries, both vaccines were associated with larger reductions (~10%), while no significant effects were detected in low-burden settings. In the African meningitis belt, PCV introduction was associated with a substantial 16.8% reduction in DALY rates (p<0.0001). No significant global association was observed for meningococcal vaccines. Interpretation: Global declines in meningitis burden are strongly associated with Hib and PCV scale-up, with the greatest benefits in high-burden settings. These findings support prioritized vaccine deployment in endemic regions to maximize public health impact. However, the presence of pre-treatment trends for Hib suggests these estimates represent vaccine-associated population-level changes rather than strictly causal effects.