title: Seroprevalence of bactericidal, specific IgG antibodies and incidence of meningitis due to group A Neisseria meningitidis by age in Burkina Faso 2008.
abstract: BACKGROUND
  We investigated serological correlates of protection against Neisseria meningitidis serogroup A (NmA) in Burkina Faso before the introduction of NmA conjugate vaccine.
  
  
  RESULTS
  We collected blood from a representative sample (N = 1022) of Bobo-Dioulasso residents. Sera were evaluated for serum bactericidal antibody (SBA) activity against NmA strains of immunotype L11 (F8238) and L10 (3125) and NmA-specific IgG. Seroprevalence was compared to the age-specific NmA meningitis incidence in Bobo-Dioulasso during March 2007-February 2008. Meningococcal carriage was evaluated in a subset (N = 538). Geometric mean titres (GMT)/concentrations (GMC) of SBA and NmA-specific IgG increased with age, peaking around age 20 years. Overall, 70% of our sample had NmA-specific IgG ≥2 ug/mL. Meningitis incidence was highest in those aged <6 months and 5-19 years. No NmA carriers were found. Compared to the reference strain SBA, GMTs were higher against a locally isolated strain and around 40-fold lower against Dutch strain 3125.
  
  
  CONCLUSIONS
  This study provides estimates of natural immunity to NmA, according to a variety of antibody measures, which will be helpful in ascertaining antibody persistence after MenAfriVac™ introduction. Age-specific seroprevalence of reference strain SBA titres most likely reflects exposure to meningococci and consecutive reactive immunity. We could not define any serological correlate of protection.
authors: School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom. caroline.trotter@bristol.ac.uk
authors: Caroline L
authors: CL
authors: Trotter
authors: Seydou
authors: S
authors: Yaro
authors: Berthe-Marie
authors: BM
authors: Njanpop-Lafourcade
authors: Aly
authors: A
authors: Drabo
authors: Sita S
authors: SS
authors: Kroman
authors: Regina S
authors: RS
authors: Idohou
authors: Oumarou
authors: O
authors: Sanou
authors: Leah
authors: L
authors: Bowen
authors: Helen
authors: H
authors: Findlow
authors: Serge
authors: S
authors: Diagbouga
authors: Bradford D
authors: BD
authors: Gessner
authors: Ray
authors: R
authors: Borrow
authors: Judith E
authors: JE
authors: Mueller
mesh_terms: D000293:Adolescent; D000328:Adult; D002050:Burkina Faso / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D007223:Infant; D008297:Male; D008585:Meningitis, Meningococcal / Q000097:blood* / Q000453:epidemiology / Q000276:immunology*; D008875:Middle Aged; D038381:Neisseria meningitidis, Serogroup A / Q000276:immunology* / Q000302:isolation & purification; D016036:Seroepidemiologic Studies; D058248:Serum Bactericidal Antibody Assay; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G