Coverage, Effectiveness and Sero-positivity of Measles-Containing Vaccines in Low- and Lower Middle-Income Countries: An Umbrella Review of Systematic Reviews and Meta-analyses

Background: Despite global investments, achieving measles elimination targets remain elusive in low-and middle-income countries (LMICs).This study provides a comprehensive synthesis of measles-containing vaccine (MCV) coverage trends, effectiveness, and uptake determinants to inform strategic realignment. Methods:We conducted an umbrella review of systematic reviews (2010-2025) and analyzed WHO/UNICEF coverage data for 79 LMICs.Determinants were synthesized via meta-meta-analysis.Results: Twelve reviews and longitudinal data for 79 countries were analyzed.In 2024, mean MCV1 coverage was 79.2% (SD=16.0%),with only 17 countries (21.5%) achieving the 95% elimination threshold.MCV2 coverage averaged 69.4% (SD=19.9%)and a mean dropout gap (difference between MCV1 and MCV2) of 10.9 percentage points.Regional disparities were profound: the regions of Americas and Africa recorded the lowest mean MCV1 coverage (74.3% and 76.8% respectively), while the African Region faced critical gaps in MCV2 (64.9%).Meta-meta-analysis identified positive maternal perception (Pooled OR=4.05; 95% CI: 2.89-5.66)and awareness of benefits (Pooled OR=2.99) as the strongest predictors of uptake.Conclusions: Fewer than one-quarter of LMICs currently meet measles elimination targets.The stagnation in coverage and significant dropout rates necessitate a strategic shift to prevent measles resurgence and protect vulnerable children.