title: Comparative Assessment of a Single Dose and a 2-dose Vaccination Series of a Quadrivalent Meningococcal CRM-conjugate Vaccine (MenACWY-CRM) in Children 2-10 Years of Age.
abstract: We compared the immunogenicity, safety and 1-year antibody persistence of a single-dose and a 2-dose series of a licensed meningococcal ACWY-CRM conjugate vaccine (MenACWY-CRM) in 2- to 10-year-old children.
  
  
  
  In this phase III, multicenter, observer-blind study, children aged 2-5 years (n = 359) and 6-10 years (n = 356) were randomized 1:1 to receive 2 doses of MenACWY-CRM (ACWY2) or 1 dose of placebo followed by 1 dose of MenACWY-CRM (ACWY1), 2 months apart. Immunogenicity was measured using serum bactericidal activity with human complement (hSBA). Primary outcomes were to assess the immunologic noninferiority and superiority of ACWY2 versus ACWY1.
  
  
  
  One-month after the second dose, the hSBA seroresponse in ACWY2 was noninferior to ACWY1 for all 4 serogroups, in both age cohorts, and was superior for serogroups C and Y in the 2- to 5-year-old age cohort and for serogroup Y in the 6- to 10-year-old age cohort. Overall, 90%-99% of subjects in ACWY2 and 65%-96% in ACWY1 had hSBA titers ≥ 8; geometric mean titers were 1.8- to 6.4-fold higher in ACWY2 than ACWY1 across serogroups. At 1 year postvaccination, geometric mean titers declined, and the differences between ACWY2 and ACWY1 remained significant for serogroups A and C in the 2- to 5-year-old age cohort and for serogroups C and Y in the 6- to 10-year-old age cohort. The safety profile of MenACWY-CRM was similar in both groups.
  
  
  
  The single dose and 2-dose MenACWY-CRM series were immunogenic and well tolerated. Although antibody responses were greater after 2 doses, especially in the 2- to 5-year-old age cohort, this difference was less pronounced at 1 year postvaccination.
authors.affiliation: From the *Alabama Clinical Therapeutics, Birmingham, Alabama; †Meridian Clinical Research, Omaha, Nebraska; ‡Advanced Clinical Research, West Jordan, Utah; §GlaxoSmithKline LLC, Cambridge, Massachusetts; and ¶GlaxoSmithKline BV, Amsterdam, The Netherlands.
authors.forename: William
authors.initials: W
authors.lastname: Johnston
authors.forename: Brandon
authors.initials: B
authors.lastname: Essink
authors.forename: Judith
authors.initials: J
authors.lastname: Kirstein
authors.forename: Eduardo
authors.initials: E
authors.lastname: Forleo-Neto
authors.forename: Sandra
authors.initials: S
authors.lastname: Percell
authors.forename: Linda
authors.initials: L
authors.lastname: Han
authors.forename: Pavitra
authors.initials: P
authors.lastname: Keshavan
authors.forename: Igor
authors.initials: I
authors.lastname: Smolenov
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003165:Complement System Proteins / Q000276:immunology; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D008589:Meningococcal Infections / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D009345:Neisseria meningitidis / Q000276:immunology*; D017063:Outcome Assessment, Health Care; D014481:United States; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; C556088:MenACWY-CRM vaccine; D022401:Meningococcal Vaccines; D003165:Complement System Proteins