title: The effect of age and recent influenza vaccination history on the immunogenicity and efficacy of 2009-10 seasonal trivalent inactivated influenza vaccination in children.
abstract: BACKGROUND
  There is some evidence that annual vaccination of trivalent inactivated influenza vaccine (TIV) may lead to reduced vaccine immunogenicity but evidence is lacking on whether vaccine efficacy is affected by prior vaccination history. The efficacy of one dose of TIV in children 6-8 y of age against influenza B is uncertain. We examined whether immunogenicity and efficacy of influenza vaccination in school-age children varied by age and past vaccination history.
  
  
  RESULTS
  We conducted a randomized controlled trial of 2009-10 TIV. Influenza vaccination history in the two preceding years was recorded. Immunogenicity was assessed by comparison of HI titers before and one month after receipt of TIV/placebo. Subjects were followed up for 11 months with symptom diaries, and respiratory specimens were collected during acute respiratory illnesses to permit confirmation of influenza virus infections. We found that previous vaccination was associated with reduced antibody responses to TIV against seasonal A(H1N1) and A(H3N2) particularly in children 9-17 y of age, but increased antibody responses to the same lineage of influenza B virus in children 6-8 y of age. Serological responses to the influenza A vaccine viruses were high regardless of vaccination history. One dose of TIV appeared to be efficacious against confirmed influenza B in children 6-8 y of age regardless of vaccination history.
  
  
  CONCLUSIONS
  Prior vaccination was associated with lower antibody titer rises following vaccination against seasonal influenza A vaccine viruses, but higher responses to influenza B among individuals primed with viruses from the same lineage in preceding years. In a year in which influenza B virus predominated, no impact of prior vaccination history was observed on vaccine efficacy against influenza B. The strains that circulated in the year of study did not allow us to study the effect of prior vaccination on vaccine efficacy against influenza A.
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: Sophia
authors.initials: S
authors.lastname: Ng
authors.forename: Dennis K M
authors.initials: DK
authors.lastname: Ip
authors.forename: Vicky J
authors.initials: VJ
authors.lastname: Fang
authors.forename: Kwok-Hung
authors.initials: KH
authors.lastname: Chan
authors.forename: Susan S
authors.initials: SS
authors.lastname: Chiu
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
authors.forename: J S Malik
authors.initials: JS
authors.lastname: Peiris
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Cowling
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D002648:Child; D005260:Female; D006801:Humans; 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*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D012621:Seasons; D013997:Time Factors; D014611:Vaccination; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated
references.citation: Stat Med. 2008 Dec 10;27(28):5880-9
references.pmid: 18752256
references.citation: Clin Infect Dis. 2010 Dec 15;51(12):1370-9
references.pmid: 21067351
references.citation: Vaccine. 2001 Sep 14;19(32):4610-7
references.pmid: 11535308
references.citation: Wkly Epidemiol Rec. 2008 Feb 29;83(9):81-7
references.pmid: 18309579
references.citation: Arch Intern Med. 1999 Jan 25;159(2):182-8
references.pmid: 9927102
references.citation: J Hyg (Lond). 1972 Dec;70(4):767-77
references.pmid: 4509641
references.citation: Pediatr Infect Dis J. 2007 Feb;26(2):107-15
references.pmid: 17259871
references.citation: Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2573-8
references.pmid: 22308500
references.citation: Vaccine. 1997 Aug-Sep;15(12-13):1323-9
references.pmid: 9302738
references.citation: Pediatrics. 2005 Jul;116(1):153-9
references.pmid: 15995046
references.citation: Vaccine. 1996 Oct;14(14):1331-9
references.pmid: 9004442
references.citation: Clin Infect Dis. 2013 May;56(10):1363-9
references.pmid: 23413420
references.citation: MMWR Morb Mortal Wkly Rep. 2012 Aug 17;61(32):613-8
references.pmid: 22895385
references.citation: Pediatrics. 2007 Jun;119(6):1076-82
references.pmid: 17545373
references.citation: Lancet Infect Dis. 2009 Dec;9(12):784-8
references.pmid: 19879807
references.citation: Pediatr Infect Dis J. 2011 Dec;30(12):1081-5
references.pmid: 21983214
references.citation: Clin Vaccine Immunol. 2011 Sep;18(9):1401-5
references.pmid: 21795459
references.citation: Influenza Other Respir Viruses. 2012 Jan;6(1):52-62
references.pmid: 21668661
references.citation: BMC Med Res Methodol. 2010 Mar 08;10:18
references.pmid: 20210985
references.citation: Am J Epidemiol. 1982 Aug;116(2):228-42
references.pmid: 7114034
references.citation: Vaccine. 2006 Apr 12;24(16):3145-52
references.pmid: 16490288
references.citation: Vaccine. 1997 Jul;15(10):1114-22
references.pmid: 9269055
references.citation: Pediatr Infect Dis J. 2003 Jan;22(1):28-34
references.pmid: 12544405
references.citation: Lancet. 1975 Feb 15;1(7903):381-3
references.pmid: 46524
references.citation: J Infect Dis. 2006 Oct 15;194(8):1032-9
references.pmid: 16991077
references.citation: PLoS One. 2008 Aug 20;3(8):e2975
references.pmid: 18714352
references.citation: Semin Pediatr Infect Dis. 2002 Apr;13(2):112-9
references.pmid: 12122949
references.citation: Pediatr Infect Dis J. 2008 Nov;27(11):1004-8
references.pmid: 18833023
references.citation: Lancet Infect Dis. 2012 Jan;12(1):36-44
references.pmid: 22032844
references.citation: Pediatr Infect Dis J. 2012 Sep;31(9):964-9
references.pmid: 22683675
references.citation: Vaccine. 1998 Dec;16(20):1929-32
references.pmid: 9796045
references.citation: Wkly Epidemiol Rec. 2007 Mar 2;82(9):69-74
references.pmid: 17333570
references.citation: Clin Infect Dis. 2012 Sep;55(5):695-702
references.pmid: 22670050
references.citation: Vaccine. 1999 May 4;17(18):2284-9
references.pmid: 10403596
references.citation: J Med Virol. 2007 Mar;79(3):320-5
references.pmid: 17245715
references.citation: Gerontology. 2007;53(6):411-8
references.pmid: 17975317
references.citation: J Infect Dis. 1999 Jan;179(1):31-6
references.pmid: 9841819