Application of seasonal trend model in influenza surveillance

Objective To Analyze the surveillance data from national influenza surveillance site in Songjiang district in Shanghai during 2006 - 2008 and predict the medical care seeking rate of influenza like illness (ILI) in 2009 by using seasonal trend model. Methods The surveillance data of influenza in Songjiang during this period were analyzed by using SAS 9.13 and Excel. Results The medical care seeking rate of ILI was 7.27% in 2006, and 5.88% in 2008, the decline trend was observed. Conclusion The seasonal trend model analysis predicted that the peak of the medical care seeking rate of ILI in Songjiang in 2009 would be during March-August. Close attention should be paid on the change of the medical care seeking rate of ILI, and timely response should be made according to reported case number and the warning line/action line in epidemic control chart to prevent the outbreak of influenza.