SARS-CoV-2 case detection using community event-based surveillance system-February-September 2020: lessons learned from Senegal

Abstract

The COVID-19 pandemic necessitated the rapid development and implementation of effective surveillance systems to detect and respond to the outbreak in Senegal. In this documentation, we describe the design and implementation of the Community Event-Based Surveillance (CEBS) system in Senegal to strengthen the existing Integrated Disease Surveillance and Response system. The CEBS system used a hotline and toll-free number to collect and triage COVID-19-related calls from the community. Data from the CEBS system were integrated with the national system for further investigation and laboratory testing. From February to September 2020, a total of 10 760 calls were received by the CEBS system, with 10 751 calls related to COVID-19. The majority of calls came from the Dakar region, which was the epicentre of the outbreak in Senegal. Of the COVID-19 calls, 50.2% were validated and referred to health districts for further investigation, and 25% of validated calls were laboratory-confirmed cases of SARS-CoV-2. The implementation of the CEBS system allowed for timely detection and response to potential COVID-19 cases, contributing to the overall surveillance efforts in the country. Lessons learned from this experience include the importance of decentralised CEBS, population sensitisation on hotlines and toll-free usage, and the potential role of Community Health Workers in triaging alerts that needs further analysis. This experience highlights the contribution of a CEBS system in Senegal and provides insights into the design and operation of such a system. The findings can inform other countries in strengthening their surveillance systems and response strategies.

Keywords: COVID-19; Public Health.

Figure 1

Flow diagram depicting the linkage between the alert system and the national system in Senegal, 2020.

Figure 2

Flow diagram of COVID-19 calls from 14 regions in Senegal, February–September 2020. *Not validated included invalidated and not classified.

Figure 3

Signals and laboratory-confirmed positive SARS-CoV-2 cases in Senegal, February–September 2020 (weeks 5–39). #Signals = number of COVID-19 calls to the alert system. #positives = number of laboratory-confirmed positive cases of SARS-CoV-2 as reported by the health district and linked to callers in the alert system. Mov. Avg = moving average.