title: Responses after one dose of a monovalent influenza A (H1N1) 2009 inactivated vaccine in Chinese population--a practical observation.
abstract: BACKGROUND
  The globally large-scale immunization was the most important method of controlling the 2009 pandemic influenza.
  
  
  METHODS
  We conducted an observational clinical trial, including 148 adults aged 18-60 years to evaluate the safety and immunogenicity of a licensed 2009 H1N1 influenza vaccine. All subjects received a single 15-μg dose of a monovalent, unadjuvanted inactivated vaccine. Antibody titers were measured by means of hemagglutinin-inhibition assays and neutralization assays based on Real-Time Cell Analyzer (RTCA) instruments at baseline, 7 days and 21 days after vaccination.
  
  
  RESULTS
  Local and systemic reactions were respectively reported by 19.1% and 22.1% of subjects. All adverse events were mild to moderate in intensity, without any deaths or serious events. By day 21 after vaccination, hemagglutinin-inhibition antibody titers of 1:40 or more were achieved in 101 of 123 (82.1%) subjects and the geometric mean titers (GMTs) increased to 1:95.27. For neutralization assays, all subjects could provide the protection against wide influenza virus, with the GMT of 1:525.44. Moreover, the rates of seroconversion, as measured using hemagglutinin-inhibition assays and neutralization assays, were 73.98% and 91.87% of subjects, respectively.
  
  
  CONCLUSIONS
  A single 15-μg dose of a monovalent, unadjuvanted inactivated 2009 H1N1 influenza vaccine was well tolerated, and induced a protective immune response in the majority of subjects aged 18-60 years (clinical trials gov number, NCT01055990).
authors.affiliation: Department of Infectious Disease, Shanghai Public Health Clinical Center Affiliated to Fudan University, Shanghai 201508, PR China.
authors.forename: Fuyan
authors.initials: F
authors.lastname: Sun
authors.forename: Yunzhi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Tian
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Renfang
authors.initials: R
authors.lastname: Zhang
authors.forename: Zhengsheng
authors.initials: Z
authors.lastname: Dai
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Tingting
authors.initials: T
authors.lastname: Li
authors.forename: Hongzhou
authors.initials: H
authors.lastname: Lu
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D002681:China; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated