INTRODUCTION: The aim of this study was to investigate the incidence of adverse effects and protective effects from influenza vaccine among elderly individuals who were vaccinated through the public healthcare system in the municipality of Tubarão, State of Santa Catarina. METHODS: A prospective cohort study was conducted between May and September 2008. A group of 341 patients was recruited, among whom 289 had been vaccinated through the public system (VSUS) and 52 had not been vaccinated (NV). The incidence of protective effects was observed by comparing the VSUS and NV groups. RESULTS: It was observed that 22.5% of the vaccinated subjects exhibited at least one adverse effect. Comparing the VSUS and NV groups in relation to the incidence of flu symptoms presented during the winter, at least one symptom was observed in 47% and 28.8% (RR = 1.11; 1.02-1.22; p = 0.0156), respectively. CONCLUSIONS: These findings demonstrate that the incidence of adverse effects was low. The high incidence of flu symptoms in the VSUS group, in comparison with NV, may be related to the profile of subjects who are in the habit of getting vaccinated against influenza.
Human influenza; Vaccines; Adverse effects; Respiratory tract infections
