Evaluation of contact tracing performance during an Ebola virus disease outbreak in a complex security environment: the case of North Kivu province, Democratic Republic of the Congo, 2018-2020.

Background: Contact tracing remains a pillar public health strategy for containing Ebola virus disease (EVD). During the 2018-2020 EVD outbreak in the Democratic Republic of the Congo (DRC), contact tracing was implemented on an unprecedented scale. Here, we assessed performance of contact tracing implemented in affected health zones, and identified risk factors associated with incomplete follow-up.

Methods: We performed a retrospective descriptive data analysis of 129,749 contacts in the contact line lists of North Kivu province between August 1, 2018 to June 25, 2020. Coverage, completeness, timeliness, and duration of contact tracing were determined to assess the performance of contact tracing implemented by field actors. Bivariate and multivariate logistic regression models were used to identify factors associated with incomplete contact tracing.

Results: Overall, more than 90% of all contacts initially identified and listed were monitored. However, 9.1% of contacts who had monitoring initiated had completed the 21 days follow-up. The median days between identification and the start of follow-up and duration contact follow-up were 3 (1-6) and 17 (12-19), respectively. The risk of incomplete follow-up was higher among contacts from urban and conflict-affected health zones.

Conclusion: Our findings indicate the necessity of prioritizing contact tracing in urban areas. This can be achieved by engaging locally trusted stakeholders to build community confidence. Furthermore, integrating digital contact tracing solutions may enhance the efficacy of traditional manual contact tracing.