The Clinical Effect of Seasonal Flu Vaccination on Health-Related Quality of Life

PURPOSE: This study aimed to determine the clinical effect of seasonal flu vaccination in adult outpatients based on the effect on health-related quality of life (HRQOL). PATIENTS AND METHODS: We reviewed the clinical data of adult flu outpatients with mild symptoms who presented to the outpatient clinic of Teikyo University Hospital, Tokyo, Japan, from 2018 to 2020 winter season and were enrolled in the prospective observational study of the clinical efficacy of anti-flu agents (UMIN000034896). We evaluated influenza vaccination status, clinical symptoms, and the status of HRQOL as measured by Short Form-8(®) (SF-8(®)) at first visit. The SF-8(®) survey generated two-component summaries; a physical component summary and a mental component summary. RESULTS: The data of 79 patients were evaluated in this study. Of the 79 patients, 37 were vaccinated for influenza at least three weeks before contracting seasonal influenza. Not every patient needed to be hospitalized for treatment. There were no significant differences in clinical backgrounds between vaccinated patients and non-vaccinated patients. Univariate analysis showed influenza vaccination was significantly associated with higher scores on the physical component summary of HRQOL (p=0.0011). CONCLUSION: Influenza vaccinations would be clinically valuable for adult outpatients with seasonal flu and mild symptoms, because they can significantly inhibit the decrease of HRQOL due to influenza infection.