The Impact of Different Types of Violence on Ebola Virus Transmission During the 2018–2020 Outbreak in the Democratic Republic of the Congo

BACKGROUND: Our understanding of the different effects of targeted versus nontargeted violence on Ebola virus (EBOV) transmission in Democratic Republic of the Congo (DRC) is limited. METHODS: We used time-series data of case counts to compare individuals in Ebola-affected health zones in DRC, April 2018–August 2019. Exposure was number of violent events per health zone, categorized into Ebola-targeted or Ebola-untargeted, and into civilian-induced, (para)military/political, or protests. Outcome was estimated daily reproduction number (R(t)) by health zone. We fit linear time-series regression to model the relationship. RESULTS: Average R(t) was 1.06 (95% confidence interval [CI], 1.02–1.11). A mean of 2.92 violent events resulted in cumulative absolute increase in R(t) of 0.10 (95% CI, .05–.15). More violent events increased EBOV transmission (P = .03). Considering violent events in the 95th percentile over a 21-day interval and its relative impact on R(t), Ebola-targeted events corresponded to R(t) of 1.52 (95% CI, 1.30–1.74), while civilian-induced events corresponded to R(t) of 1.43 (95% CI, 1.21–1.35). Untargeted events corresponded to R(t) of 1.18 (95% CI, 1.02–1.35); among these, militia/political or ville morte events increased transmission. CONCLUSIONS: Ebola-targeted violence, primarily driven by civilian-induced events, had the largest impact on EBOV transmission.