Evaluation of influenza surveillance in Baiyin,2009-2015

Objective To evaluate the performance of influenza surveillance in Baiyin, Gansu province, and provide evidence for the influenza surveillance evaluation at city level. Methods According to the National Influenza Surveillance Evaluation Protocol and local situation, the performance of influenza surveillance in Baiyin was evaluated by using the data from sentinel hospitals, laboratory network and outbreak surveillance. Results From 2009 to 2015, the average score of influenza surveillance comprehensive evaluation was 73.25, the highest score was 88.75 in 2015. In two sentinel hospitals, the timely weekly reporting rate of influenza like illness (ILI) was always 90.00%, no underreporting occurred, the weekly qualified sampling rate had been 90.00% since 2013(trend2=42.613,P=0.000; trend2=17.356, P=0.000), the timely detection rates of samples were 53.91%, 40.89% respectively. In local network laboratories, the timely detection rate of nucleic acid of influenza virus showed an increasing trend (trend2=272.189, P=0.000), the verifying consistent rate increased from 73.08% to 98.00%(trend2=20.129, P=0.000), all the positive samples were subtyped and the correct rate of blind sample assessment was 100.00%, but the chick-embryo isolation of influenza virus needed to be improved, and the virus strains timely sent to national influenza center were insufficient. A total of 28 ILI outbreaks were reported during this period, the surveillance management was performed well. Conclusion The influenza surveillance quality has been improved significantly in Baiyin, but it is still necessary to strengthen the surveillance in sentinel hospitals, and the chick-embryo isolation rate of influenza virus should be further improved in local network laboratories.