title: Persistence of the immune response at 5 years of age following infant immunisation with investigational quadrivalent MenACWY conjugate vaccine formulations.
abstract: OBJECTIVE
  Serogroup A, C, W-135 and Y meningococcal (MenACWY) conjugate vaccines are recommended for routine adolescent immunisation in the United States and Canada. We evaluated the persistence of bactericidal antibodies through early childhood, following infant immunisation with varying schedules of MenACWY-CRM(197) vaccine.
  
  
  METHODS
  UK and Canadian infants were immunised with 2-3 doses of MenACWY-CRM(197) or 2 doses of serogroup C meningococcal (MenC) conjugate vaccine, and either MenACWY-CRM(197), 1/5 dose of MenACWY polysaccharide vaccine or no booster at 12 months. Control groups recruited at 60 months had received country-specific infant doses of MenC conjugate vaccine. hSBA titres were measured in participants at 40 and 60 months of age.
  
  
  RESULTS
  382 children were enrolled in 12 groups (22-40 per group). By age 60 months, 3-11% of children primed and boosted with MenACWY-CRM(197) had hSBA titres≥1:8 against serogroup A, 14-45% against serogroup C, 57-85% against serogroup W-135 and 42-71% against serogroup Y. Children primed with MenC and boosted with MenACWY-CRM(197) had similar results, except for serogroup C (59%). In age-matched controls administered MenC vaccine at 2, 3, and 4 months (UK), 2 and 12 months or 12 months only (Canada), percentages with hSBA titres≥1:8 were 0-3%, 29-53%, 34-36% and 10-29% against serogroups A, C, W-135 and Y respectively.
  
  
  CONCLUSIONS
  Serogroup-specific bactericidal antibody wane following infant immunisation with MenACWY-CRM(197), most markedly against serogroup A. Best persistence against serogroup C is observed with MenC conjugate vaccine priming and MenACWY-CRM(197) at 12 months, compared to schedules using only MenACWY-CRM(197), with the potential for providing broader protection compared to monovalent MenC vaccines alone.
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, University of Oxford, UK. ameneh.khatami@paediatrics.ox.ac.uk
authors.forename: Ameneh
authors.initials: A
authors.lastname: Khatami
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Snape
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Davis
authors.forename: Helen
authors.initials: H
authors.lastname: Layton
authors.forename: Tessa
authors.initials: T
authors.lastname: John
authors.forename: Ly-Mee
authors.initials: LM
authors.lastname: Yu
authors.forename: Peter M
authors.initials: PM
authors.lastname: Dull
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gill
authors.forename: Tatjana
authors.initials: T
authors.lastname: Odrjlin
authors.forename: Simon
authors.initials: S
authors.lastname: Dobson
authors.forename: Scott A
authors.initials: SA
authors.lastname: Halperin
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Langley
authors.forename: Shelly A
authors.initials: SA
authors.lastname: McNeil
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pollard
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood; D001770:Blood Bactericidal Activity; D002170:Canada; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D050296:Microbial Viability; D009345:Neisseria meningitidis / Q000276:immunology / Q000502:physiology; D013997:Time Factors; D006113:United Kingdom; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; C525703:MenACWY; D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate