title: A clinical study to assess the immunogenicity and safety of a monovalent 2009 influenza A (H1N1) vaccine in an area with low-level epidemics of pandemic influenza.
abstract: We conducted a multi-center, randomized, laboratory-blinded clinical trial in 185 healthy adults (<60 years) and 107 elders (>60 years) to examine the immunogenicity and safety of different doses of an inactivated, monovalent, non-adjuvanted, split vaccine against the 2009 pandemic influenza A (H1N1) virus. The 186 adults were assigned to three treatment groups, i.e., one 15 μg hemagglutination (HA) antigen dose, two 15 μg or 30 μg HA doses in 3 weeks apart, and the 107 elders were treated with two 15 μg or 30 μg doses in 3 weeks apart. Prior to the vaccination, 4.8% subjects had hemagglutination-inhibition (HAI) antibody titers of 1:40 or more. By day 21 post-vaccination of one dose of 15 μg HA, the seroprotective rate was 95.1% and 75.5% in subjects <60 and >65 years of age, respectively; by day 21 post the second 15 μg HA dose, the seroprotective rates were 93.2% and 73.1%, respectively. The seroprotective rates for recipients of 30 μg HA antigen by day 21 were 95.2% for subjects <60 years and 81.1% for subjects >65 years of age, that was boosted to 98.3% and 80.4%, respectively with a second dose of 30 μg HA antigen. No vaccine-related serious adverse events occurred. The data indicated a single 15 μg HA dose of the vaccine induced a protective immune response in most adults, including the elders >60 years of age, and a booster dose at the third week did not render a higher level of antibody response.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Hsiang-Chi
authors.initials: HC
authors.lastname: Kung
authors.forename: Kuo-Chin
authors.initials: KC
authors.lastname: Huang
authors.forename: Tsui-Mai
authors.initials: TM
authors.lastname: Kao
authors.forename: Yi-Chien
authors.initials: YC
authors.lastname: Lee
authors.forename: Feng-Yee
authors.initials: FY
authors.lastname: Chang
authors.forename: Ning-Chi
authors.initials: NC
authors.lastname: Wang
authors.forename: Yung-Ching
authors.initials: YC
authors.lastname: Liu
authors.forename: Wen-Sen
authors.initials: WS
authors.lastname: Lee
authors.forename: Hsing-Jin
authors.initials: HJ
authors.lastname: Liu
authors.forename: Chin-I
authors.initials: CI
authors.lastname: Chen
authors.forename: Chien-Hui
authors.initials: CH
authors.lastname: Chen
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Huang
authors.forename: Szu-Min
authors.initials: SM
authors.lastname: Hsieh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation; D058872:Epidemics / Q000517:prevention & control*; D005260:Female; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D013624:Taiwan / Q000453:epidemiology; D014611:Vaccination / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines