Characteristics of Influenza-like Illness Patients in the Community’s Hospital and the Efficacy of Influenza Vaccination

Background: A few studies have investigated the clinical characteristics of influenza-like illness and the efficacy of influenza vaccination. We retrospectively evaluated the clinical characteristics of patients with influenza-like illness. Methods: A total of 2,344 patients who showed signs of influenza-like illness between January 2014 and February 2014 were included in this study. Among them, 515 patients had been tested by reverse transcription-polymerase chain reaction and rapid antigen testing. We compared the influenza vaccination group with the influenza non-vaccination group and correlation to high risk group. Results: The influenza vaccination group showed significantly lower prevalence of influenza than the influenza non-vaccination group (odds ratio, 0.665; P< 0.001). There was significantly lower odds ratio of influenza associated with influenza vaccination in the high-risk group for influenza (odds ratio, 0.504; P< 0.001). No significant difference was found between the influenza vaccination group and influenza non-vaccination group in terms of patient demographics or associated symptoms. Conclusion: Influenza vaccination is effective in the prevention of influenza. Further, influenza vaccination is a more effective prevention in the high-risk group for influenza.