Armed conflict and infectious disease: quantifying the association between mortality rate due to war and terrorism and measles incidence, 2000-2019

Abstract

Achieving the measles elimination goals included in the Measles and Rubella Strategic Framework 2021-2030 requires understanding the key factors driving the continued transmission of measles. Armed conflict is established as a factor in the continued delays in achieving polio eradication. Here, we investigate if armed conflict also plays a role in the spread of measles. We investigate evidence of changes to surveillance system quality during periods of conflict, generate conflict-free counterfactual estimates of vaccine coverage, and produce conflict-free counterfactual estimates of measles incidence in 106 countries from 2000 to 2019. To estimate incidence, we used war and terrorism mortality rate as a predictor in a mixed-effects linear model of measles incidence, controlling for our conflict-free counterfactual first- and second-dose measles vaccine coverage estimates and estimates of the war-associated decrease in vaccine coverage. We estimate that across all countries and years Syria has measles incidence most affected by war and terrorism, with 78.0% (23.3-96.8) of incidence in 2012 associated with war and terrorism. We cannot expect to eliminate measles without addressing armed conflict, however, we also find notable data gaps, highlighting the need for improved data collection and estimation methods in countries experiencing conflict.