title: Lack of serum bactericidal activity in preschool children two years after a single dose of serogroup C meningococcal polysaccharide-protein conjugate vaccine.
abstract: BACKGROUND
  There is an increased risk of invasive meningococcal disease during the teenage years. A cohort of children vaccinated with a single dose of meningococcal C protein-polysaccharide conjugate (MenC) vaccine in early childhood during the U.K. catch up campaign will enter this age group during the coming decade. The duration of protective immunity against invasive meningococcal C disease provided by this single dose regimen is uncertain.A serum bactericidal titer of <1/8 correlates with susceptibility to invasive meningococcal disease. We assessed this correlate of protection in a cohort of children approximately 2 years after a single dose of vaccine.
  
  
  METHODS
  Serum bactericidal activity was assessed in 94 children (median age, 4.0 years) at a median time of 1.8 years after vaccination.
  
  
  RESULTS
  Of the 94 children, 59 (63%) had a serum bactericidal titer <1/8.
  
  
  CONCLUSIONS
  The data from this study add to previous evidence indicating that immunity wanes rapidly after vaccination with serogroup C meningococcal glycoconjugate vaccines in infancy and early childhood. Such observations suggest that booster doses of MenC vaccine may be needed to maintain the successful contribution this vaccine has made to child health in the United Kingdom.
authors.affiliation: Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom. matthew.snape@paediatrics.ox.ac.uk
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Snape
authors.forename: Dominic F
authors.initials: DF
authors.lastname: Kelly
authors.forename: Ben
authors.initials: B
authors.lastname: Green
authors.forename: E Richard
authors.initials: ER
authors.lastname: Moxon
authors.forename: Ray
authors.initials: R
authors.lastname: Borrow
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pollard
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D001770:Blood Bactericidal Activity; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D038542:Neisseria meningitidis, Serogroup C / Q000276:immunology*; D013997:Time Factors; D018074:Vaccines, Conjugate / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate; C410218:serogroup C meningococcal conjugate vaccine