title: Evaluation of age-related differences in the immunogenicity of a G9 H9N2 influenza vaccine.
abstract: Avian influenza A/H9N2 viruses can infect people and are viruses considered to be a potential pandemic threat. Prior studies with an inactivated G1 clade H9N2 vaccine reported that persons born before 1968 were more likely to have an immune response than younger subjects. We performed a randomized, double-blind trial to evaluate whether immune responses following immunization with an inactivated, unadjuvanted influenza G9 H9N2 vaccine prepared from A/chicken/Hong Kong/G9/97 virus were more frequent in persons born in 1964 or earlier (44-59 years) than in those born in 1970 or later (18-38 years). One hundred twenty one persons were randomized to receive two doses of either 7.5- or 30-mcg of hemagglutinin intramuscularly. Post-vaccination serum antibody responses as measured by hemagglutination inhibition and microneutralization were either similar in the two age cohorts or greater in the younger age group. Persons born before 1968 were not more likely to respond to a G9 H9N2 influenza vaccine than persons born in 1970 or later.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, TX, USA. ratmar@bcm.edu
authors.forename: Robert L
authors.initials: RL
authors.lastname: Atmar
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Keitel
authors.forename: John M
authors.initials: JM
authors.lastname: Quarles
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Cate
authors.forename: Shital M
authors.initials: SM
authors.lastname: Patel
authors.forename: Diane
authors.initials: D
authors.lastname: Nino
authors.forename: Janet
authors.initials: J
authors.lastname: Wells
authors.forename: Nancy
authors.initials: N
authors.lastname: Arden
authors.forename: Kuo
authors.initials: K
authors.lastname: Guo
authors.forename: Heather
authors.initials: H
authors.lastname: Hill
authors.forename: Robert B
authors.initials: RB
authors.lastname: Couch
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000914:Antibodies, Viral / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053127:Influenza A Virus, H9N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated