title: H1N1 antibody persistence 1 year after immunization with an adjuvanted or whole-virion pandemic vaccine and immunogenicity and reactogenicity of subsequent seasonal influenza vaccine: a multicenter follow-on study.
abstract: BACKGROUND
  We investigated antibody persistence in children 1 year after 2 doses of either an AS03(B)-adjuvanted split-virion or nonadjuvanted whole-virion monovalent pandemic influenza vaccine and assessed the immunogenicity and reactogenicity of a subsequent dose of trivalent influenza vaccine (TIV).
  
  
  METHODS
  Children previously immunized at age 6 months to 12 years in the original study were invited to participate. After a blood sample was obtained to assess persistence of antibody against swine influenza A/H1N1(2009) pandemic influenza, children received 1 dose of 2010/2011 TIV, reactogenicity data were collected for 7 days, and another blood sample was obtained 21 days after vaccination.
  
  
  RESULTS
  Of 323 children recruited, 302 received TIV. Antibody persistence (defined as microneutralization [MN] titer ≥1:40) 1 year after initial vaccination was significantly higher in the AS03(B)-adjuvanted compared with the whole-virion vaccine group, 100% (95% confidence interval [CI], 94.1%-100%) vs 32.4% (95% CI, 21.5%-44.8%) in children immunized <3 years old and 96.9% (95% CI, 91.3%-99.4%) vs 65.9% (95% CI, 55.3%-75.5%) in those 3-12 years old at immunization, respectively (P < .001 for both groups). All children receiving TIV had post-vaccination MN titers ≥1:40. Although TIV was well tolerated in all groups, reactogenicity in children <5 years old was slightly greater in those who originally received AS03(B)-adjuvanted vaccine.
  
  
  CONCLUSIONS
  This study provides serological evidence that 2 doses of AS03(B)-adjuvanted pandemic influenza vaccine may be sufficient to maintain protection across 2 influenza seasons. Administration of TIV to children who previously received 2 doses of either pandemic influenza vaccine is safe and is immunogenic for the H1N1 strain.
authors.affiliation: Southampton NIHR Wellcome Trust Clinical Research Facility, Faculty of Medicine, University of Southampton, United Kingdom.
authors.forename: Woolf T
authors.initials: WT
authors.lastname: Walker
authors.forename: Philip
authors.initials: P
authors.lastname: de Whalley
authors.forename: Nick
authors.initials: N
authors.lastname: Andrews
authors.forename: Clarissa
authors.initials: C
authors.lastname: Oeser
authors.forename: Michelle
authors.initials: M
authors.lastname: Casey
authors.forename: Louise
authors.initials: L
authors.lastname: Michaelis
authors.forename: Katja
authors.initials: K
authors.lastname: Hoschler
authors.forename: Caroline
authors.initials: C
authors.lastname: Harrill
authors.forename: Phoebe
authors.initials: P
authors.lastname: Moulsdale
authors.forename: Ben
authors.initials: B
authors.lastname: Thompson
authors.forename: Claire
authors.initials: C
authors.lastname: Jones
authors.forename: Jem
authors.initials: J
authors.lastname: Chalk
authors.forename: Simon
authors.initials: S
authors.lastname: Kerridge
authors.forename: Tessa M
authors.initials: TM
authors.lastname: John
authors.forename: Ifeanyichukwu
authors.initials: I
authors.lastname: Okike
authors.forename: Shamez
authors.initials: S
authors.lastname: Ladhani
authors.forename: Richard
authors.initials: R
authors.lastname: Tomlinson
authors.forename: Paul T
authors.initials: PT
authors.lastname: Heath
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Miller
authors.forename: Saul N
authors.initials: SN
authors.lastname: Faust
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Snape
authors.forename: Adam
authors.initials: A
authors.lastname: Finn
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pollard
mesh_terms: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D005500:Follow-Up Studies; 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*; D007251:Influenza, Human / Q000276:immunology* / Q000517:prevention & control*; D009500:Neutralization Tests; D014771:Virion / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines