title: Long-term immunogenicity and safety after a single dose of the quadrivalent meningococcal serogroups A, C, W, and Y tetanus toxoid conjugate vaccine in adolescents and adults: 5-year follow-up of an open, randomized trial.
abstract: BACKGROUND
  Long-term protection against meningococcal disease is associated with persistence of post-vaccination antibodies at protective levels. We evaluated the bactericidal antibody persistence and safety of the quadrivalent meningococcal serogroups A, C, W and Y tetanus-toxoid conjugate vaccine (MenACWY-TT) and the meningococcal polysaccharide serogroups A, C, W, and Y vaccine (MenACWY-PS) up to 5 years post-vaccination.
  
  
  METHODS
  This phase IIb, open, randomized, controlled study conducted in the Philippines and Saudi Arabia consisted of a vaccination phase and a long-term persistence phase. Healthy adolescents and adults aged 11-55 years were randomized (3:1) to receive a single dose of MenACWY-TT (ACWY-TT group) or MenACWY-PS (Men-PS group). Primary and persistence results up to 3 years post-vaccination have been previously reported. Antibody responses against meningococcal serogroups A, C, W, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA, cut-off titers 1:8 and 1:128) at Year 4 and Year 5 post-vaccination. Vaccine-related serious adverse events (SAEs) and cases of meningococcal disease were assessed up to Year 5.
  
  
  RESULTS
  Of the 500 vaccinated participants, 404 returned for the Year 5 study visit (Total Cohort Year 5). For the Total Cohort Year 5, 71.6-90.0 and 64.9-86.3 % of MenACWY-TT recipients had rSBA titers ≥1:8 and ≥1:128, respectively, compared to 24.8-74.3 and 21.0-68.6 % of MenACWY-PS recipients. The rSBA geometric mean titers (GMTs) remained above the pre-vaccination levels in both treatment groups. Exploratory analyses suggested that both rSBA GMTs as well as the percentages of participants with rSBA titers above the cut-offs were higher in the ACWY-TT than in the Men-PS group for serogroups A, W and Y, with no apparent difference for MenC. No SAEs related to vaccination or cases of meningococcal disease were reported up to Year 5.
  
  
  CONCLUSIONS
  These results suggest that a single dose of MenACWY-TT could protect at least 72 % of vaccinated adolescents and adults against meningococcal disease at least 5 years post-vaccination.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00356369.
authors.affiliation: Research Institute for Tropical Medicine, Corporate Ave, Muntinlupa City, 1781, Metro Manila, Philippines. cbtabora@yahoo.com.
authors.forename: Charissa Fay Corazon
authors.initials: CF
authors.lastname: Borja-Tabora
authors.affiliation: Philippine General Hospital Manila, Taft Avenue, Ermita, Manila, 1000, Metro Manila, Philippines. csmontalban@gmail.com.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Montalban
authors.affiliation: College of Medicine, Alfaisal University, Al Zahrawi Street, Al Maather, Al Takhassusi Rd, Riyadh, 11533, Saudi Arabia. zmemish@yahoo.com.
authors.forename: Ziad A
authors.initials: ZA
authors.lastname: Memish
authors.affiliation: GSK Vaccines, Avenue Fleming 20, B- 1300, Wavre, Belgium. dominique.boutriau@gsk.com.
authors.forename: Dominique
authors.initials: D
authors.lastname: Boutriau
authors.affiliation: GSK Pharmaceuticals Limited, Embassy Links, #5, SRT Road, Bangalore, 560052, India. devayani.a.kolhe@gsk.com.
authors.forename: Devayani
authors.initials: D
authors.lastname: Kolhe
authors.affiliation: GSK Vaccines, 2301 Renaissance Blvd, King of Prussia, PA, 19406, USA.
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Miller
authors.affiliation: GSK Vaccines, Avenue Fleming 20, B- 1300, Wavre, Belgium. jacqueline.m.miller@gsk.com.
authors.forename: Marie
authors.initials: M
authors.lastname: Van der Wielen
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008589:Meningococcal Infections / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000276:immunology*; D008875:Middle Aged; D011817:Rabbits; D065288:Serogroup; D013997:Time Factors; D016896:Treatment Outcome; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000276:immunology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; C525703:MenACWY; D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate; C576777:tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine