A community-based confinement strategy to reduce the spread of Ebola Virus Disease: An analysis of the 2018-2020 outbreak in the DRC.

Abstract BackgroundDespite tremendous progress on Ebola Virus Disease (EVD), challenges remain in the implementation of holistic strategies to quickly stop outbreaks. We investigated the effectiveness of a community-based confinement strategy to limit the spread of EVD during the tenth documented EVD outbreak in the Democratic Republic of the Congo (DRC), 2018 - 2020.MethodsWe did a community-based, open-label, two-group, unrandomized controlled intervention. Eligible participants were EVD contacts registered by epidemiological surveillance teams from November 2019 to May 2020 in the two last hotspots (Beni and Mabalako Health Zones). Intervention group participants were confined in specific community sites of their preference for the duration of their follow-up. Control group participants underwent CT without confinement and were allowed to continue their daily activities. The primary outcome was the number of confirmed secondary cases in the two groups. Secondary outcomes included delay between symptom onset and isolation, case fatality rate, survival rate, and vaccination rate. Data were analyzed using various quantitative methods.FindingsA total of 27,324 EVD contacts were included in the study. 585 contacts were confined and followed up (‘the intervention group’), and 26,739 were followed up without confinement. The intervention group generated 32 confirmed cases (5.5%) in the first generation, while the control group generated just 87 (0.3%). However, the 32 confirmed cases from the intervention contacts did not generate any onward transmission (R=0.00), whereas the 87 confirmed cases from the non-intervention group generated 99 secondary cases (R = 1.14). Results for the secondary outcomes showed significant difference between the two groups. The delay between symptom onset and case isolation was shorter (1.3 vs 4.8 days; p<0.0000), CFR lower (12.5% vs. 52.9%; p=0.0001), and vaccination rate higher (86.0% vs 56.8%; p<0.0000) in the intervention group compared to the control group. A significant difference was also found between intervention and control groups in survival rate at the 16-day follow-up (87.9% vs. 47.7%, respectively; p=0.0004).InterpretationThe community-based confinement strategy used in DRC is effective for the rapid cessation of EVD transmission, highlighting the importance of rapidly implemented, innovative and community-oriented control strategies.