g. from clinically defined influenza like-illness (ILI) in the outpatient setting to laboratory confirmed hospitalisations for influenza), they found efficacy estimates of around 70%, higher than those on effectiveness (around 40%). Despite the fact that influenza vaccination is primarily recommended in Modulators children with underlying conditions, insufficient evidence is available in this population. Moreover, the World Health Organization considers as a target group for influenza immunisation, children from 6 to 23 months, even though effectiveness data are scanty [16]. The objective of this national study was to determine the effectiveness of seasonal influenza vaccination against laboratory-confirmed influenza

cases CSF-1R inhibitor visiting the Emergency Department (hospitalised or not) in a large paediatric population over two consecutive seasons (2011–2012 and 2012–2013) and to provide evidence for vaccination recommendations in Italy. In Italy, since 1999 an active surveillance on drug and vaccine safety in children has been conducted in various paediatric hospitals/wards Gemcitabine located throughout the country

[17]. Italian paediatric hospitals/wards can admit children from 0 to 17 years of age. Overall, the network includes 11 sites from seven regions representative of the whole Country, and around 400,000 children visited the EDs of the participating centres each year. The network organisation facilitated the prompt set up of the investigation on influenza vaccine effectiveness during the A/H1N1 pandemic (in 2009) and in two following influenza seasons (2011–2012 and 2012–2013). The results of the A/H1N1 pandemic vaccination campaign were reported elsewhere [18]. Consecutive children visiting the Emergency Departments (ED) with an ILI, as diagnosed by the doctor during the ED visit, were eligible for the study. The ILI case definition for children was about adapted from the European Centre for Disease Control (ECDC) and used for influenza surveillance in Europe since the pandemic season [19] and [20]. In detail, the following

definition of ILI was adopted, for children >5 years: sudden onset of fever ≥38 °C (for at least 24 h), in association with at least one respiratory symptom (cough, sore throat, coryza), and at least one general symptom (headache, asthenia, malaise). For children between 6 months and 5 years, in association with fever >38 °C, the following general signs and symptoms were considered: inadequate drinking or feeding, vomiting and/or diarrhoea, respiratory symptoms. All children hospitalised, or admitted to a Short Stay Unit (up to 24 h observation) were enrolled, and in some clinical centres also children visiting the ED but not admitted to hospital were included. Since influenza vaccine is indicated for children aged >6 months, younger children were not eligible. Written informed consent was acquired from parents.