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

BACKGROUND: Influenza-like illness occurs annually worldwide, with peak timing and severity varying seasonally, resulting in significant annual mortality. OBJECTIVES: There were three objectives: (1) to describe the epidemiological and clinical features of hospitalised patients with severe acute respiratory infection caused by influenza and other respiratory viruses (ORVs); (2) to report the influenza seasonality in the region and (3) to correlate findings of influenza circulation and immunisation time in Brazil. PATIENTS/METHODS: This study took place in three Brazilian hospitals located in cities with different climatic conditions (Curitiba (south), Rio de Janeiro (south-east) and Fortaleza (north-east)). Patients presenting with an acute process with indication for admission consisting of a predefined set of conditions potentially associated with recent influenza infection were enrolled. RESULTS: We screened 1666 patients, with 595 meeting the inclusion criteria. Influenza viruses and ORVs were detected in 6.5% and 59% of patients, respectively. Influenza-positive cases fell into the severe spectrum as compared with those with ORVs (30% vs 11%), but without any difference in mortality rates. Epidemiological results revealed variations in the peak time of influenza infections between north-east (Fortaleza) and south (Curitiba) Brazil, basically following the rain period of each region. In north-east Brazil, viral circulation was prevalent in the first 4 months of the year, indicating that the vaccination campaign occurred in a postseasonal period, possibly explaining the low effectiveness. CONCLUSIONS: The active-surveillance model is a valuable tool for investigating respiratory virus impact on hospitalised patients, with influenza-infection monitoring enabling implementation of adequate preventive measures.

Molecular characterization and clinical epidemiology of human respiratory syncytial virus (HRSV) A and B in hospitalized children, Southern Brazil.

Human respiratory syncytial virus (HRSV) is a major etiologic agent of pediatric respiratory infections. Genetic variability of its glycoprotein G enables HRSV to evade the immune response and determines its seasonal dissemination. This study reports genetic variability and clinical profiles of HRSV-infected patients from Southern Brazil. Seventy positive samples, 78% type A and 22% type B, were analyzed. Of the patients (median age, 6 months; interquartile range, 2-11 years), 16% had co-morbidities and 17% developed severe disease. The ON1 HRSV genotype first appeared in 2012, and patients infected with this genotype showed an increased tendency to develop severe disease.