title: Antibody persistence and response to a booster dose of a quadrivalent conjugate vaccine for meningococcal disease in adolescents.
abstract: BACKGROUND
  In a previous randomized phase 2 study in adolescents, a CRM197 meningococcal conjugate vaccine against serogroups A, C, W-135 and Y (MenACWY-CRM) was well tolerated and immunogenic, compared with a plain polysaccharide vaccine (MenACWY-PS).
  
  
  METHODS
  This extension study assessed antibody persistence 5 years after primary vaccination with MenACWY-CRM (n = 50) or MenACWY-PS (n = 51), and the immunogenicity and reactogenicity of a dose of MenACWY-CRM given 5 years after primary vaccination; antibody response was also compared with vaccine-naive controls (n = 54). The primary endpoints were the percentage of subjects with titers ≥8 by serum bactericidal activity assay using human complement (hSBA) 5 years after primary vaccination and hSBA geometric mean titers 1 month after the MenACWY-CRM dose given in the current study.
  
  
  RESULTS
  Five years after primary vaccination, over 70% of subjects who had received MenACWY-CRM were seropositive (hSBA titers ≥8) for serogroups C, W-135 and Y; for serogroups C and Y, the percentages of seropositive subjects were significantly higher in subjects previously vaccinated with MenACWY-CRM than in subjects previously vaccinated with MenACWY-PS. The MenACWY-CRM dose given 5 years postprimary vaccination elicited an anamnestic response across serogroups in those previously vaccinated with MenACWY-CRM. Responses in those previously vaccinated with MenACWY-PS were less robust but adequate and similar to that seen in the vaccine-naive group, both in magnitude and kinetics. MenACWY-CRM was well tolerated in all 3 groups.
  
  
  CONCLUSIONS
  MenACWY-CRM provided a broad and persistent immune response in adolescents. A subsequent dose of MenACWY-CRM elicited an adequate antibody response, regardless of vaccine history.
authors.affiliation: Novartis Vaccines and Diagnostics, Cambridge, MA 02139, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Jacobson
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Jackson
authors.forename: Keith
authors.initials: K
authors.lastname: Reisinger
authors.forename: Allen
authors.initials: A
authors.lastname: Izu
authors.forename: Tatjana
authors.initials: T
authors.lastname: Odrljin
authors.forename: Peter M
authors.initials: PM
authors.lastname: Dull
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood*; D001770:Blood Bactericidal Activity; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D008297:Male; D008589:Meningococcal Infections / Q000276:immunology / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D013997:Time Factors; D014611:Vaccination / Q000379:methods*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; C556088:MenACWY-CRM vaccine; D022401:Meningococcal Vaccines