title: [Epidemiological characteristics on the clustering nature of pandemic (H1N1) 2009 in China].
abstract: OBJECTIVE
  To study the epidemiological characteristics on the clustering nature of pandemic (H1N1) 2009 in China.
  
  
  METHODS
  Time and place distribution of pandemic (H1N1) 2009 on the nature of clustering through data from Public Health Emergency Management Information System were described.
  
  
  RESULTS
  As of August 10, 2010, 2773 pandemic (H1N1) 2009 clusters, a total of 77 363 cases (including 20 deaths) were reported in the mainland of China. The most reported number of clusters was from schools and kindergartens with the total number of 2498 (accounted for 90.08% of the total number). Middle schools appeared the have the most clusters (1223, accounting for 48.96%). The number of clusters reported in the southern provinces (cities) accounted for 77.03% of the total, and was more than that in the northern provinces (cities). Two reported peaks in the southern provinces (cities) were in June and November, 2009, respectively. There was only one reported peak in the northern provinces in September, 2009.
  
  
  CONCLUSIONS
  Time and place distribution characteristics on the clusters of pandemic (H1N1) 2009 were similar to the seasonal influenza, but the beginning of winter peak was much earlier and intensity of reporting was much higher on the clusters of pandemic (H1N1) 2009 than that of seasonal influenza.
authors.affiliation: Institute of Virus Control and Prevention, China.
authors.forename: Jing-hong
authors.initials: JH
authors.lastname: Shi
authors.forename: Ni-juan
authors.initials: NJ
authors.lastname: Xiang
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Shan-hua
authors.initials: SH
authors.lastname: Sun
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Fan
authors.initials: F
authors.lastname: Yuan
authors.forename: Li-jie
authors.initials: LJ
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Li-mei
authors.initials: LM
authors.lastname: Yang
authors.forename: Pei-long
authors.initials: PL
authors.lastname: Li
authors.forename: Chun-xiang
authors.initials: CX
authors.lastname: Fan
authors.forename: Dao-wei
authors.initials: DW
authors.lastname: Yang
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.forename: Qing-long
authors.initials: QL
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Zong
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Cui-ling
authors.initials: CL
authors.lastname: Xu
authors.forename: Yue-long
authors.initials: YL
authors.lastname: Shu
authors.forename: Zi-jian
authors.initials: ZJ
authors.lastname: Feng
mesh_terms: D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004196:Disease Outbreaks; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology*