title: The Global Influenza Hospital Surveillance Network (GIHSN): a new platform to describe the epidemiology of severe influenza.
abstract: BACKGROUND
  Influenza is a global public health problem. However, severe influenza only recently has been addressed in routine surveillance.
  
  
  OBJECTIVE
  The Global Influenza Hospital Surveillance Network (GIHSN) was established to study the epidemiology of severe influenza in consecutive seasons in different countries. Our objective is to describe the GIHSN approach and methods.
  
  
  METHODS
  The GIHSN uses prospective active surveillance to identify consecutive influenza admissions in permanent residents of well-defined geographic areas in sites around the world. A core common protocol is followed. After consent, data are collected on patient characteristics and clinical outcomes, respiratory swabs are obtained, and the presence of influenza virus and subtype or lineage is ascertained by polymerase chain reaction. Data are collated and analyzed at the GIHSN coordination center.
  
  
  RESULTS
  The GIHSN has run its activities for two consecutive influenza seasons, 2012-2013 and 2013-2014, and hospitals in Brazil, China, France, Russian Federation, Turkey, and Spain have been involved in one or both seasons. Consistency on the application of the protocol and heterogeneity for the first season have been addressed in two previous publications. During both seasons, 19 677 eligible admissions were recorded; 11 843 (60%) were included and tested, and 2713 (23%) were positive for influenza: 991 (37%) A(H1N1); 807 (30%) A(H3N2); 583 (21%) B/Yamagata; 56 (2%) B/Victoria and 151 (6%) influenza A; and 125 (5%) influenza B were not characterized.
  
  
  CONCLUSIONS
  The GIHSN is a platform that provides information on severe influenza worldwide, applying a common core protocol and a consistent case definition.
authors.affiliation: Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), Valencia, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Puig-Barberà
authors.affiliation: Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), Valencia, Spain.
authors.forename: Anita
authors.initials: A
authors.lastname: Tormos
authors.affiliation: D.I. Ivanovsky Institute of Virology, Moscow, Russian Federation.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Trushakova
authors.affiliation: Research Institute of Influenza, St. Petersburg, Russian Federation.
authors.forename: Anna
authors.initials: A
authors.lastname: Sominina
authors.affiliation: Research Institute of Influenza, St. Petersburg, Russian Federation.
authors.forename: Maria
authors.initials: M
authors.lastname: Pisareva
authors.affiliation: National Influenza Reference Laboratory Capa-Istanbul, Istanbul, Turkey.
authors.forename: Meral A
authors.initials: MA
authors.lastname: Ciblak
authors.affiliation: National Influenza Reference Laboratory Capa-Istanbul, Istanbul, Turkey.
authors.forename: Selim
authors.initials: S
authors.lastname: Badur
authors.affiliation: Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Yu
authors.affiliation: Li Ka Shing Faculty of Medicine, School of Public Health, The University of Hong Kong, Hong Kong, China.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Cowling
authors.affiliation: D.I. Ivanovsky Institute of Virology, Moscow, Russian Federation.
authors.forename: Elena
authors.initials: E
authors.lastname: Burtseva
keywords: Hospital; influenza epidemiology; surveillance network