Evaluation of two WHO First International Standards for Vi polysaccharide from Citrobacter freundii and Salmonella enterica subspecies enterica serovar Typhi.
Biologicals
; 57: 34-45, 2019 Jan.
Article
em En
| MEDLINE
| ID: mdl-30502020
ABSTRACT
Numerous Vi capsular polysaccharide (Vi PS) conjugate vaccines to protect young children and infants from Typhoid are either licensed or under development. These vaccines are evaluated by laboratory methods to ensure their potency and that quality requirement are met. International Standard (IS) preparations of Vi PS are needed to calibrate and harmonise these assays. Twenty laboratories from 12 countries participated in a collaborative study to evaluate two candidate ISs Citrobacter freundii Vi PS (NIBSC code 12/244) and Salmonella enterica serovar Typhi Vi PS (16/126). On the basis of returned results and stability profiles, these standards were established by the WHO Expert Committee on Biological Standardization in Oct 2017 as the First WHO IS for C. freundii Vi PS with a content of 1.94⯱â¯0.12â¯mg Vi PS per ampoule (expanded uncertainty with coverage factor of kâ¯=â¯2.11 corresponding to a 95% level of confidence) and the First WHO IS for S. Typhi Vi PS with a content of 2.03⯱â¯0.10â¯mg Vi PS per ampoule (expanded uncertainty with coverage factor of kâ¯=â¯2.11), as determined by quantitative NMR. The study also showed the ISs are suitable for physicochemical and immuno assays used for the quantitation of the Vi PS component in Vi PS and conjugate vaccines.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Polissacarídeos Bacterianos
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Salmonella typhi
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Febre Tifoide
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Vacinas Tíficas-Paratíficas
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Citrobacter freundii
Tipo de estudo:
Clinical_trials
Limite:
Child
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Humans
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article