Evaluation of the sentinel surveillance system for influenza-like illness and severe acute respiratory infection in Ethiopia during the COVID-19 pandemic, 2021-2023.

BACKGROUND

The World Health Organization (WHO) recommends periodic evaluation of influenza surveillance systems. Such information would enable countries to assess the performance of their surveillance systems, identify shortfalls for improvement, and provide evidence of data reliability for policymaking and public health interventions. However, such data is lacking after the integration of other respiratory viruses into the existing influenza sentinel surveillance system in Ethiopia.

METHODS

We evaluated a total of 20 influenza-like illness (ILI)/ severe acute respiratory infection (SARI) sentinel sites using CDC guidelines that focused on the performance of the system from January 2021 to December 2023. The performance of the system was evaluated using ten surveillance attributes: (i) data quality and completeness for key variables, (ii) timeliness, (iii) representativeness, (iv) simplicity, (v) acceptability, (vi) utility, (vii) flexibility, (viii) stability, (ix) Sustainability, and (x) sensitivity. A structured evaluation tool consisting of 57 indicators was adopted with modifications from standard surveillance system evaluation guidelines and similar studies conducted in other African countries. Data were collected through record review (including CRFs, case enrollment logs, weekly reports, laboratory registrations, guidelines, bulletins, and publications) and interviews of key personnel across the surveillance system. Each indicator was scored out of 100% using the weighted average. The overall mean score of the attribute was scored from 1 to 3 and categorized as follows: < 60% weak performance; 60-79% moderate performance; ≥80% good performance.

RESULTS

About 18,724 cases were enrolled in ILI/SARI sentinel sites between January 2021 and December 2023 in the country. Among the total enrolled cases, Influenza, SARS-CoV-2, and RSV were detected in 1,648, 937, and 1,164 patients respectively. The overall mean score of the system during the study period was 2.5 (moderate to good performance). The evaluation showed that data quality and completeness, timeliness, simplicity, and stability were scored moderate to good performance while acceptability and sustainability measured weak performance. From the total indicators, 37(65%) of them scored good performance, however only 3(5%) of them scored weak performance.

CONCLUSIONS

The overall performance of ILI/SARI sentinel surveillance was assessed as moderate to good. Data quality, completeness, timeliness, simplicity, and stability were rated as moderate to good. However, the acceptability and sustainability of the surveillance system require further attention to enhance the overall effectiveness of ILI/SARI sentinel surveillance in the country.