title: Reduced antibody response to revaccination with meningococcal serogroup A polysaccharide vaccine in adults.
abstract: Widespread use of meningococcal A and C polysaccharide (MACP) vaccines has raised concerns about induction of hyporesponsiveness to these polysaccharides. Immunological hyporesponsiveness to C polysaccharide has been clearly documented in infants, children and adults but only limited data from Gambian children are available for A polysaccharide. We investigated whether a second dose of MACP, given 6 months after an initial dose affected the immunological response as measured by the serum bactericidal assay (SBA) and enzyme-linked immunosorbent assay (ELISA), to serogroup A meningococci in young adults (university students, n=36). Serogroup A SBA responses 1 month following the second dose of MACP (geometric mean titre (GMT) 103.6, 95% CI 45.6-235.1) were approximately one third of the levels observed 1 month post first dose (GMT 281.9, 95% CI 134.9-581.4). The serogroup A-specific IgG levels post second dose (GMC 21.2, 95% CI 15.3-29.4) were also significantly lower at an average of three-quarters the level post first dose (GMC 28.7, 95% CI 20.8-39.7). This confirms that revaccination with MACP vaccine, 6 months following the initial dose, results in a reduced immunological response to A polysaccharide in adults. Repeated vaccination with MACP vaccine may be ineffective and development and use of meningococcal serogroup A conjugate vaccines should be encouraged.
authors.affiliation: Meningococcal Reference Unit, Manchester Public Health Laboratory, Withington Hospital, Nell Lane, West Didsbury, M20 2LR, Manchester, UK. rborrow@nw.phls.nhs.uk
authors.forename: R
authors.initials: R
authors.lastname: Borrow
authors.forename: H
authors.initials: H
authors.lastname: Joseph
authors.forename: N
authors.initials: N
authors.lastname: Andrews
authors.forename: M
authors.initials: M
authors.lastname: Acuna
authors.forename: E
authors.initials: E
authors.lastname: Longworth
authors.forename: S
authors.initials: S
authors.lastname: Martin
authors.forename: N
authors.initials: N
authors.lastname: Peake
authors.forename: R
authors.initials: R
authors.lastname: Rahim
authors.forename: P
authors.initials: P
authors.lastname: Richmond
authors.forename: E
authors.initials: E
authors.lastname: Kaczmarski
authors.forename: E
authors.initials: E
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D008297:Male; D022401:Meningococcal Vaccines / Q000276:immunology*; D009345:Neisseria meningitidis / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D012703:Serotyping; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; D011135:Polysaccharides, Bacterial