title: Regional variation in mortality impact of the 2009 A(H1N1) influenza pandemic in China.
abstract: BACKGROUND
  Laboratory-confirmed deaths grossly underestimate influenza mortality burden, so that reliable burden estimates are derived from indirect statistical studies, which are scarce in low- and middle-income settings.
  
  
  OBJECTIVE
  Here, we used statistical excess mortality models to estimate the burden of seasonal and pandemic influenza in China.
  
  
  METHODS
  We modeled data from a nationally representative population-based death registration system, combined with influenza virological surveillance data, to estimate influenza-associated excess mortality for the 2004-2005 through 2009-2010 seasons, by age and region.
  
  
  RESULTS
  The A(H1N1) pandemic was associated with 11·4-12·1 excess respiratory and circulatory (R&C) deaths per 100,000 population in rural sites of northern and southern China during 2009-2010; these rates were 2·2-2·8 times higher than those of urban sites (P<0·01). Influenza B accounted for a larger proportion of deaths than pandemic A(H1N1) in 2009-2010 in some regions. Nationally, we attribute 126,200 (95% CI, 61,000-248,400) excess R&C deaths (rate of 9·4/100,000) and 2,323,000 (1,166,000-4,533,000) years of life lost (YLL) to the first year of A(H1N1)pdm circulation.
  
  
  CONCLUSIONS
  The A(H1N1) pandemic posed a mortality and YLL burden comparable to that of interpandemic influenza in China. Our high burden estimates in rural areas highlight the need to enhance epidemiological surveillance and healthcare services, in underdeveloped and remote areas.
authors.affiliation: Department of Epidemiology and Statistics, Public Health School, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Yu
authors.forename: Luzhao
authors.initials: L
authors.lastname: Feng
authors.forename: Cecile G
authors.initials: CG
authors.lastname: Viboud
authors.forename: David K
authors.initials: DK
authors.lastname: Shay
authors.forename: Yong
authors.initials: Y
authors.lastname: Jiang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhou
authors.forename: Maigeng
authors.initials: M
authors.lastname: Zhou
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xu
authors.forename: Nan
authors.initials: N
authors.lastname: Hu
authors.forename: Weizhong
authors.initials: W
authors.lastname: Yang
authors.forename: Shaofa
authors.initials: S
authors.lastname: Nie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D005843:Geography; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000401:mortality* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D058873:Pandemics; D016019:Survival Analysis; D055815:Young Adult
keywords: A(H1N1) pandemic; China; influenza; mortality; negative binomial model; regional variation