title: Evaluation of candidate international standards for meningococcal serogroups A and X polysaccharide.
abstract: Polysaccharide (PS) based meningococcal vaccines are primarily evaluated by physicochemical methods to ensure batches are consistently manufactured. As PS content is determined by different methods across numerous laboratories, there is a need for International Standards (IS) to calibrate the assays. Following the successful introduction of the WHO Meningococcal group C (MenC) IS in 2011, NIBSC initiated projects to prepare similar standards for groups A, W, Y and X (MenA/W/Y/X) to standardise all meningococcal- PS based vaccines. On the basis of results from a collaborative study to evaluate preparations of MenA and MenX PS, both were established by the WHO Expert Committee on Biological Standardization in Oct 2015 as; the First WHO International Standard for the Meningococcal Group A polysaccharide with a content of 0.845 ± 0.043 mg MenA PS per ampoule (expanded uncertainty with coverage factor of k=2.45 corresponding to a 95% level of confidence); the First WHO International Standard for the Meningococcal Group X polysaccharide with a content of 0.776 ± 0.089 mg MenX PS per ampoule (expanded uncertainty with coverage factor of k=2.45), as determined by quantitative NMR. The standards are available from NIBSC, who act as guardians and distributors of the material under the auspices of WHO.
authors.affiliation: Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK. Electronic address: caroline.vipond@nibsc.org.
authors.forename: Caroline
authors.initials: C
authors.lastname: Vipond
authors.affiliation: Laboratory for Molecular Structure, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Swann
authors.affiliation: Biostatistics, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Dougall
authors.affiliation: Biostatistics, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Rigsby
authors.affiliation: Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Fang
authors.initials: F
authors.lastname: Gao
authors.affiliation: Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Beresford
authors.affiliation: Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC), Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Barbara
authors.initials: B
authors.lastname: Bolgiano
mesh_terms: D006801:Humans; D022401:Meningococcal Vaccines / Q000737:chemistry / Q000302:isolation & purification / Q000592:standards; D038381:Neisseria meningitidis, Serogroup A / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000302:isolation & purification / Q000592:standards
chemical_list: D022401:Meningococcal Vaccines; D011135:Polysaccharides, Bacterial
keywords: Group A polysaccharide; Group X polysaccharide; International Standard; Meningococcal vaccine; Neisseria meningitidis