title: Immunogenicity, Safety and Antibody Persistence of a Booster Dose of Quadrivalent Meningococcal ACWY-tetanus Toxoid Conjugate Vaccine Compared with Monovalent Meningococcal Serogroup C Vaccine Administered Four Years After Primary Vaccination Using the Same Vaccines.
abstract: BACKGROUND
  We evaluated safety, immunogenicity and antibody persistence of meningococcal serogroups A, C, W and Y tetanus toxoid conjugate vaccine (MenACWY-TT) booster vaccination 4 years after priming of toddlers.
  
  
  METHODS
  This phase III, open-label, controlled study in Finland (NCT00955682) enrolled children previously randomized (3:1) at 12-23 months (NCT00474266) to receive 1 dose of MenACWY-TT or MenC conjugate vaccine (MenC-CRM197). Serum bactericidal antibody titers using rabbit (rSBA, cut-off 1:8) and human complement (hSBA, cut-off 1:8) were assessed at year 3 and 4 after priming and 1 month and 1 year after administration of a booster dose of the same vaccine given for primary vaccination. Reactogenicity and safety were assessed, and vaccination-related serious adverse events were recorded from the time of primary vaccination.
  
  
  RESULTS
  Before booster (year 4), 74.1%, 40.4%, 49.3% and 58.2% of MenACWY-TT-recipients retained rSBA titers ≥1:8 for serogroups A, C, W and Y, respectively; 28.8%, 73.2%, 80.6% and 65.4% retained hSBA ≥1:8. Percentages for the MenC-CRM group were 35.6% (rSBA-MenC) and 46.9% (hSBA-MenC). After MenACWY-TT booster, ≥99.5% had rSBA ≥1:8 and hSBA ≥1:8 for each serogroup. After MenC-CRM197 booster, all children had rSBA-MenC ≥1:8 and hSBA-MenC ≥1:8. At year 5, percentages above the cut-off were ≥97.4% (rSBA) and ≥95.5% (hSBA) in MenACWY-TT-vaccinees for each serogroup. The MenACWY-TT booster dose had a clinically acceptable safety profile. No vaccine-related serious adverse events were reported.
  
  
  CONCLUSIONS
  There was evidence of antibody persistence 4 years after toddlers were primed with MenACWY-TT. Booster vaccination induced robust immune responses for all serogroups with an acceptable safety profile.
authors.affiliation: From the *Vaccine Research Center, University of Tampere Medical School, Tampere, Finland; † Clinical R&D, GSK Vaccines, Wavre, Belgium; and ‡Vaccines Discovery & Development, GSK Vaccines, King of Prussia, Pennsylvania.
authors.forename: Timo
authors.initials: T
authors.lastname: Vesikari
authors.forename: Aino
authors.initials: A
authors.lastname: Forsten
authors.forename: Veronique
authors.initials: V
authors.lastname: Bianco
authors.forename: Marie
authors.initials: M
authors.lastname: Van der Wielen
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Miller
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D008589:Meningococcal Infections / Q000276:immunology / Q000517:prevention & control; D022401:Meningococcal Vaccines / Q000009:adverse effects* / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000009:adverse effects* / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate; C576777:tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine