title: Hemagglutination inhibiting antibody persistence 1 year after influenza vaccination in Korean children and adolescents.
abstract: This study aimed to assess the 1-y immunogenicity of influenza vaccines and the association between immunogenicity at 1 m and further influenza infections in children aged 6 m to 18 y. Serum hemagglutination inhibition (HI) antibody titers and GMTs were determined for the recommended influenza strains 0, 1, 6, and 12 m post-vaccination. The serological evidence of influenza infections were defined as the increase of HI titer (HI ≥1:40 and 4-fold rise). The seroprotection rates for strains A(H1N1), A(H3N2), and B were 91.2%, 87.6%, and 87.6%, respectively, at 1 month (n = 174). These rates were 76.5%, 64.7%, and 54.6%, respectively, at 12 m. The seroprotection rates and GMTs for influenza A(H1N1) and A(H3N2) were higher at 12 m than at 0 m (p < 0.05) but not for B. There were 39 subjects (42 cases) of serological influenza infections. Subjects with seroprotection at 1 m post-vaccination had showed fewer serologic A(H1N1) (10.1 vs 54.5%) and A(H3N2) (7.2 vs 38.1%) infections than the ones with HI titer <1:40 during follow-up (P < 0.01). In conclusion, influenza vaccines used during the 2008-09 season induced adequate 1-y immunogenicity for A(H1N1) and A(H3N2). The immunogenicity at one month after vaccination influenced further serological influenza infections.
authors.affiliation: a Department of Pediatrics , Dongguk University Ilsan Hospital , Goyang , South Korea.
authors.forename: Eun Kyeong
authors.initials: EK
authors.lastname: Kang
authors.affiliation: b Department of Pediatrics , Eulji General Hospitl , Seoul , South Korea.
authors.forename: Byung Wook
authors.initials: BW
authors.lastname: Eun
authors.affiliation: c Department of Pediatrics , Inje University Ilsan Paik Hospital , Goyang , South Korea.
authors.forename: Nam Hee
authors.initials: NH
authors.lastname: Kim
authors.affiliation: d Department of Pediatrics , Korea University Ansan Hospital , Ansan , South Korea.
authors.forename: Yun Kyung
authors.initials: YK
authors.lastname: Kim
authors.affiliation: e Department of Pediatrics , Korea Cancer Center Hospital , Seoul , South Korea.
authors.forename: Jung Sub
authors.initials: JS
authors.lastname: Lim
authors.affiliation: e Department of Pediatrics , Korea Cancer Center Hospital , Seoul , South Korea.
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology; D009981:Influenza B virus / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D008297:Male; D056910:Republic of Korea; D013997:Time Factors
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines
keywords: 1-year immunogenicity; children; hemagglutination inhibition; influenza vaccine; seroprotection rate