CONTRIBUTION OF COMMUNITY-BASED SURVEILLANCE TO ACUTE FLACCID PARALYSIS SURVEILLANCE IN INSECURITY CONTEXT, BATHA AND HADJER-LAMIS PROVINCES – CHAD, 2012 – 2022

Abstract

Intro: Disease outbreaks, in insecurity settings grow rapidly due to weakened public health systems. In such areas, Community-Based Surveillance (CBS) can contribute to strengthen Acute Flaccid Paralysis (AFP) surveillance. Since 2015, Chad implements CBS in Batha and Hadjer-Lamis provinces but its performance is less documented. We aimed to describe the CBS contribution in the detection, notification and investigation of AFP cases. Methods: It's a cross-sectional study that included all AFP cases reported by surveillance system from week-1, 2012 to week-22, 2022. We reviewed the national database to extract data and performed a descriptive analysis. To assess CBS's contribution, we calculated proportions and compared the Non- polio AFP rate (NPAFP-R), district reporting, notification and investigation timelines and stool samples quality over two periods: before CBS, 2012-2014 (P1) and during CBS, 2015-2022 (P2). Findings: During P1, the overall NPAFP-R per 100,000 under 15 boys and girls were 5.2 and 5.8 in 2012 respectively, 6.0/3.1 in 2014. In P2, it was 5.9/5.4 in 2015, 11.2/9.2 in 2019 and 19.0/16.1 in 2022. During P2, CBS reported 97.2% (341/351) and 98.1%(259/264) of male and female cases. Silent districts represented 33.3%(3/9) in P1 and 0.0%(0/13) since 2018 in P2. The cases with two stool samples collected within 14 days in females ranged from 85.7%(42/49) in P1 to 86.2%(299/347) in P2 while it was respectively 89.6%(60/67) and 91.0% (437/480) in males. The samples received to the laboratory in good condition in females were 87.8%(43/49) in P1 and 93.7%(325/347) in P2 while it was respectively 79.1%(53/67) and 91.1%(442/480) in males. The proportion of cases notified within 7 days after paralysis onset in males and females was respectively 59.7%(40/67) versus 59.6%(286/480) and 63.3%(31/49) versus 57.1%(198/347). Conclusion: CBS in insecurity areas contributed to increase surveillance's sensitivity and sample quality. However, the notification timeline doesn't reflect its reactivity. Training, supervision and monitoring could further improve performance.