Epidemiologic characteristics of influenza in Shanghai from 2013 to 2015

Objective To study the epidemiologic characters of influenza in Shanghai from 2013 to 2015. Methods Data of outpatient visits for influenza-like illness (ILI) were collected through influenza surveillance hospitals. Pathogenic surveillance to part of ILI samples was conducted. Results From 2013 to 2015, the ILI consultation rate ranged from 0.68%~3.73%, with an average rate of 1.46%. In total 51 445 samples were collected, and 12673 samples were positive, with the positive rate of 24.63%. The ratio of the patient visited for ILI aged from 25 to 60 was higher than other groups. Conclusion The peak of epidemic of influenza in Shanghai was in winter and summer. The ratio of the patients visited for ILI aged over 60 increased with years. More measures should be taken to protect the elder people.