Fig. 3

Violin plots depicting the densities of observed data for each predictor variable by the diphtheria status of each administrative level 1 (ADM1) region. “Diphtheria present” regions reported diphtheria cases at least once during 2017–2024 (ADM1 regions, N = 47), whereas “diphtheria absent” regions were never classified as diphtheria present during the study period (ADM1 regions, N = 494). The vertical gray lines within each density plot indicate the minimum, 25th quartile, median, 75th quartile, and maximum values, respectively. A The cumulative population-adjusted counts of conflict-related fatalities from 2013 to 2024 for each administrative level 1 (ADM1) region in the analysis, with the x-axis on a log scale for readability. B The time-weighted average of survey-estimated childhood three-dose diphtheria-tetanus-pertussis vaccination coverage for each ADM1 region from 2017 to 2024