Global Influenza Hospital-based Surveillance Network (GIHSN): results of surveillance of influenza and other respiratory viruses in hospitalised patients in Brazil, 2015

Raboni, Sonia M; Moura, Fernanda EA; Caetano, Braulia C; Avanzi, Valéria M; Pereira, Luciane A; Nogueira, Meri B; Vidal, Luine R; Tavares, Isabel CF; Pradel, Florence K; Picot, Valentina S; Puig-Barbera, Joan; Siqueira, Marilda M

Patients of all ages, who were admitted for any acute condition described as potentially associated to influenza, were considered eligible for enrollment in the study. To be included, eligible patients were identified in the hospital admission registries and had to comply with all of the following criteria: i) admission within 24 to 72 h prior to recruitment; ii) be a resident in the area of the study (defined for each site) and belong to the base population source; and iii) a referred history of any acute condition associated to influenza with onset within 7 days or less prior to admission to the hospital. The study used the European CDC definition for ILI, which included at least one out of four systemic symptoms (fever, headache, myalgia, or malaise) and at least one out of three respiratory symptoms (cough, sore throat, or shortness of breath).