Xo_GripeEffectiveness Assessment of Vaccinating Schoolchildren Against Influenza the in São Paulo, 2009

Children and adolescents play an important role in sustaining the transmission of influenza. Moreover, with the occurrence of influenza in children, there are important socioeconomic consequences to families affected by the disease, related to absenteeism, expenditure on health services and medication use. This study presents an evaluation of direct and indirect effectiveness of influenza vaccination in school age children and their unvaccinated household contacts. It was conducted in 2009, in Sao Paulo - Brazil, through a randomized double-blind community trial, with six months of follow up. For the evaluation of vaccine effectiveness, the influenza vaccine was used for the experimental group, and meningitis conjugate and varicella vaccines for the control group. After vaccination, the volunteers and their families were followed for six months, in order to identify cases of acute respiratory infection (ARI) and to collect biological samples for testing with RT-PCR for diagnosis of influenza.