Objective: To evaluate the performance of China Infectious Disease Automated-alert and Response System (CIDARS).
Methods: A retrospective analysis was conducted on data related to the warning signals, the outcome of signal verification, the field investigation of CIDARS, and the emergent events reported through Public Health Emergency Events Surveillance System from July 1, 2008 to June 30, 2010 in Zhejiang province. The performance of CIDARS was qualitatively evaluated by indicators on its sensitivity and rate of false alarm.
Results: In total, 26 446 signals were generated by the system which involving 17 diseases, with an average of 2.83 signals per country per week. Among all the signals, 99.95% of them were responded. 0.90% of the signals were judged as suspected events via the preliminary verification, and 30 outbreaks were finally confirmed by field investigation. The sensitivity of the system was 69.77% with the false alarm rate as 1.39%.
Conclusion: The system seemed to have worked on the outbreak early warning of infectious diseases and could directly reflect the anomaly event emerged from the infectious disease reporting system. However, more efforts should be paid to the following areas as how to decrease the false positive signals, select suitable thresholds and increase the quality of data in order to enhance the accuracy of the system.