title: Clinical Characteristics and Mortality of Influenza A H1N1 and Influenza-Like Illness in Mexico City in the 2013-2014 Winter Season.
abstract: BACKGROUND
  The 2013-2014 influenza season in Mexico City was severe and mainly due to influenza A H1N1, as was the 2009 pandemic.
  
  
  OBJECTIVE
  To describe features of the outbreak and to compare the characteristics of patients with and without viral identification.
  
  
  METHODS
  We reviewed the medical charts of all individuals with influenza or influenza-like illness admitted to a referral hospital for respiratory diseases in Mexico City from January 2013 to March 2014, whether influenza virus was identified or not.
  
  
  RESULTS
  We included 233 patients with influenza-like illness, 99 of whom had laboratory confirmed influenza; one-half of all patients required mechanical ventilation and 25% were admitted to the intensive care unit. Patients with confirmed influenza had a more severe disease than those without confirmation. A total of 52 (22.3%) patients died in hospital; survival was greater among patients hospitalized in the intensive care unit compared with those who remained in regular wards.
  
  
  CONCLUSIONS
  Influenza A H1N1 continues to cause significant outbreaks in Mexico City. Patients with influenza-like illness had a similar clinical course regardless of laboratory confirmation of influenza, suggesting that their illness likely belonged to the same outbreak. Mechanical ventilation in regular hospital wards may be lifesaving, although the outcome is worse than at an intensive care unit.
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: David
authors.initials: D
authors.lastname: Martínez-Briseño
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Luis
authors.initials: L
authors.lastname: Torre-Bouscoulet
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Julio de Jesús
authors.initials: Jde J
authors.lastname: Herrera-Zamora
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Julián
authors.initials: J
authors.lastname: Díaz-Rico
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Sandoval-Macías
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Rogelio
authors.initials: R
authors.lastname: Pérez-Padilla
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Carmen
authors.initials: C
authors.lastname: Hernández-Cárdenas
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Justin
authors.initials: J
authors.lastname: Regalado-Pineda
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Jorge
authors.initials: J
authors.lastname: Salas-Hernández
authors.affiliation: Instituto Nacional de Enfermedades Respiratorias (INER), Mexico City, Mexico.
authors.forename: Patricio
authors.initials: P
authors.lastname: Santillán-Doherty
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology* / Q000401:mortality / Q000821:virology; D007362:Intensive Care Units / Q000706:statistics & numerical data; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012621:Seasons