title: Severe, critical and fatal cases of 2009 H1N1 influenza in China.
abstract: OBJECTIVE
  For severe, critical and fatal cases of 2009 H1N1 influenza in the winter in the Northern Hemisphere, the detailed features are not fully known. The aim of this study was to examine these features through describing these cases in Beijing, China in 2009.
  
  
  METHODS
  Data on severe, critical and fatal cases were collected via the Notifiable Disease Surveillance System and a designated surveillance system for managing 2009 H1N1 influenza cases in Beijing. The characteristics and risk factors of these cases were elucidated.
  
  
  RESULTS
  A total of 475 severe cases, 73 critical ones and 69 deaths were identified in 2009. The proportion of obesity was low, as well as pregnancy. About half of them had no underlying disease. Most of deaths had multi-organ failure, with a median interval from illness onset to death of ten days. Delay in visiting hospital, cardiovascular disease and allergy predicted a higher risk of severe disease, and cases aged 6-17 years were at lower risk. Cases not promptly receiving neuraminidase inhibitors were at increased risk of death.
  
  
  CONCLUSIONS
  Age and underlying disease are significantly associated with severity of outcomes of 2009 H1N1 influenza; prompt presentation to hospital and use of neuraminidase inhibitor were protective.
authors.affiliation: Beijing Center for Disease Prevention and Control, Capital Medical University School of Public Health and Family Medicine, No.16 He Pingli Middle Street, Dongcheng District, Beijing, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Yang
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.forename: Xinghuo
authors.initials: X
authors.lastname: Pang
authors.forename: Weixian
authors.initials: W
authors.lastname: Shi
authors.forename: Xinyu
authors.initials: X
authors.lastname: Li
authors.forename: Lili
authors.initials: L
authors.lastname: Tian
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Huang
authors.forename: Macintyre C
authors.initials: MC
authors.lastname: Raina
authors.forename: Quanyi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000998:Antiviral Agents / Q000627:therapeutic use; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000453:epidemiology / Q000473:pathology / Q000821:virology; D009765:Obesity / Q000150:complications / Q000453:epidemiology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D000998:Antiviral Agents