Incidence of Influenza-like Illness after Influenza Vaccination in the Elderly

ABSTRACT

BACKGROUND: The purpose of our study was to assess the efficacy of influenza vaccination against influenza-like illness and the common cold in the elderly. METHODS: A total of 62 subjects, aged 60 years or older, were evaluated, who visited the Un-bong Welfare center, Bansong, Pusan. Attack rate of influenza-like illness and the common cold during winter, before and after influenza vaccination, was assessed by means of interview. RESULTS: After influenza vaccination, the attack frequency of influenza-like illness during winter was 0.07 0.31. This differed with 0.81 1.17 before vaccination (P<0.000). After influenza vaccination, the attack frequency of the common cold during winter was 1.22 1.61. This differed with 2.71 2.35 before vaccination (P<0.000). After influenza vaccination, the attack rate of influenza-like illness during winter was 45.2%. This differed with 4.8% before vaccination (P<0.000). After influenza vaccination, the attack frequency of common cold during winter was 87.1%. This differed with 48.4% before vaccination (P<0.000). The only side effect of influenza vaccination was pain (1.6%). CONCLUSION: In the elderly, influenza vaccination may reduce the incidence of influenza-like illness and the common cold during winter.