title: [Serologic survey on pandemic influenza A (H1N1) virus among aged ≥ 3 years population from Jiangsu province in 2009, China].
abstract: OBJECTIVE
  To understand the antibody levels against pandemic influenza A (H1N1) virus (2009 H1N1) among aged ≥ 3 years population in 2009, from Jiangsu province, and to describe the distribution of 2009 H1N1.
  
  
  METHODS
  Serum specimens were collected from natural populations at four different periods in Jiangsu, and tested with hemagglutination-inhibition (HI) assays. Rates of protective antibody against 2009 H1N1 and Geometric mean titers (GMTs) were estimated.
  
  
  RESULTS
  The rates of protective antibody against 2009 H1N1 rose with the progress of epidemics in Jiangsu, which were 3.46%, 7.59%, 16.94%, respectively in July, August and November, 2009. There were no significant differences on the rates of protective antibody between males and females at four different cross-sectional periods (P > 0.05), and no significant differences on GMTs were observed at different periods except for November 2009. Significant differences on rates of protective antibody and GMTs among various age groups were observed at four different periods (P < 0.05), and similar results were observed among different periods in various age groups (P < 0.05). There were significant differences on rates of protective antibody and GMTs among different areas (P < 0.05).
  
  
  CONCLUSIONS
  The 2009 H1N1 strain had been widely spread out in Jiangsu province since July 2009. People aged 12 - 17 years became the major victims after August. As of November 2009, the rate of protective antibody against 2009 H1N1 was still low, predicting that the epidemic might continue to exist for a certain period of time.
authors.affiliation: Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China.
authors.forename: Fen-yang
authors.initials: FY
authors.lastname: Tang
authors.forename: Rong-qiang
authors.initials: RQ
authors.lastname: Zu
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Xian
authors.initials: X
authors.lastname: Qi
authors.forename: Hong
authors.initials: H
authors.lastname: Ji
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Jian-guang
authors.initials: JG
authors.lastname: Fu
authors.forename: Yuan-fang
authors.initials: YF
authors.lastname: Qin
authors.forename: Fei
authors.initials: F
authors.lastname: Deng
authors.forename: Hai-tao
authors.initials: HT
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000097:blood / Q000453:epidemiology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral