Evaluation of the Integrated Epidemiological Surveillance System in Chad according to the CDC method.

Background: The Integrated Epidemiological Surveillance System (IESS) is an essential pillar of public health, in the detection and rapid response to priority diseases. In Chad, despite its existence, the persistence of structural weaknesses influences its functioning, which justifies this study. Aim: This article aims to determine the current performance of the IESS in Chad, with a view to identifying possible shortcomings and proposing corrective measures. Setting: An evaluative cross-sectional study was conducted from 16 September 2024 to 15 January 2025, in eight provincial health delegations in Chad. Methods: The collected primary and secondary data were analysed according to the five pillars of the Centres for Disease Control and Prevention (CDC) evaluation methodology: operation, usefulness, importance, cost and quality of the IESS. Results: The quality of IESS in Chad - evaluated by the CDC method - is considered low with an overall score of 44% (other pillars have been evaluated otherwise). The acceptability (87%) and simplicity (72%) of this system are its strengths. Although acceptable, the flexibility (56%) and responsiveness (55%) of the system need to be improved. The weak points that justify this low quality overall are its low sensitivity (29%) and positive predictive value (29%), as well as its very low representativeness (27%). This overall assessment seems obvious given the weaknesses identified in terms of operation, usefulness, importance and cost of IESS in Chad. Conclusion: The IESS in Chad remains generally functional but is of low quality. Contribution: This study innovates mainly because of its rigorous application of the five pillars of the CDC method for assessing the current performance of Chad's IESS in 2024.