title: Persistence of Meningococcal Antibodies and Response to a Third Dose After a Two-dose Vaccination Series with Investigational MenABCWY Vaccine Formulations in Adolescents.
abstract: BACKGROUND
  In a primary study, healthy adolescents received 2 doses (months 0/2) of 1 of the 4 investigational meningococcal ABCWY vaccine formulations, containing components of licensed quadrivalent glycoconjugate vaccine MenACWY-CRM, combined with different amounts of recombinant proteins (rMenB) and outer membrane vesicles (OMV) from a licensed serogroup B vaccine, or 2 doses of rMenB alone or 1 dose of MenACWY-CRM then a placebo.
  
  
  METHODS
  This phase 2 extension study evaluated antibody persistence up to 10 months after the 2-dose series and the immunogenicity and safety of a third dose (month 6). Immune responses against serogroups ACWY and serogroup B test strains were measured by serum bactericidal assay with human complement.
  
  
  RESULTS
  At month 12, antibody persistence against serogroups ACWY in all 2-dose MenABCWY groups was at least comparable with the 1-dose MenACWY-CRM group. Bactericidal antibodies against most serogroup B test strains declined by month 6, then plateaued over the subsequent 6 months, with overall higher antibody persistence associated with OMV-containing formulations. A third MenABCWY vaccine dose induced robust immune responses against vaccine antigens, although antibody levels 6 months later were comparable with those observed 5 months after the 2-dose series. All investigational MenABCWY vaccines were well tolerated.
  
  
  CONCLUSIONS
  Two or three doses of investigational MenABCWY vaccines elicited immune responses against serogroups ACWY that were at least comparable with those after 1 dose of MenACWY-CRM. After either vaccination series, investigational MenABCWY vaccine formulations containing OMV had the highest immunogenicity against most serogroup B test strains. No safety concerns were identified in this study.
authors.affiliation: From the *Hospital del Niño, Panama City, Panama, †Centro de Investigacion CAFAM, Colombia; ‡Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile; §Novartis Pharma BV, Amsterdam, The Netherlands; and ¶Novartis Vaccines and Diagnostics, Inc., Cambridge, Massachusetts.
authors.forename: Xavier
authors.initials: X
authors.lastname: Saez-Llorens
authors.forename: Diana Catalina
authors.initials: DC
authors.lastname: Aguilera Vaca
authors.forename: Katia
authors.initials: K
authors.lastname: Abarca
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Maho
authors.forename: Linda
authors.initials: L
authors.lastname: Han
authors.forename: Igor
authors.initials: I
authors.lastname: Smolenov
authors.forename: Peter
authors.initials: P
authors.lastname: Dull
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008589:Meningococcal Infections / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate