An Outbreak of Typhoid Fever, Xing‐An County, People's Republic of China, 1999: Estimation of the Field Effectiveness of Vi Polysaccharide Typhoid Vaccine

Yang, Hong; Kilgore, Paul E.; Yang, Ling Hong; Park, Jin-Kyung; Pan, You Fu; Kim, Yongdai; Lee, Young-Jack; Zhang, Xu; Clemens, John D.

doi:10.1086/320729

Cited by 49 publications

(29 citation statements)

References 32 publications

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“…Typhoid Vi polysaccharide vaccines have been used in mass vaccination campaigns in several Asian countries where typhoid fever is endemic and its epidemiology is well understood. 12,16,18,19 The success of vaccination campaigns has influenced WHO to recommend consideration of the use of these vaccines to target high-risk groups in countries where typhoid is endemic and to control epidemics. 12 Social scientists have investigated behavioral, sociocultural, political, and economic factors that may influence vaccine acceptance.…”

Section: Introductionmentioning

confidence: 99%

Formative Investigation of Acceptability of Typhoid Vaccine During a Typhoid Fever Outbreak in Neno District, Malawi

Blum¹,

Dentz²,

Chingoli³

et al. 2014

The American Journal of Tropical Medicine and Hygiene

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Abstract. Typhoid fever affects an estimated 22 million people annually and causes 216,000 deaths worldwide. We conducted an investigation in August and September 2010 to examine the acceptability of typhoid vaccine in Neno District, Malawi where a typhoid outbreak was ongoing. We used qualitative methods, including freelisting exercises, key informant and in-depth interviews, and group discussions. Respondents associated illness with exposure to "bad wind," and transmission was believed to be airborne. Typhoid was considered extremely dangerous because of its rapid spread, the debilitating conditions it produced, the number of related fatalities, and the perception that it was highly contagious. Respondents were skeptical about the effectiveness of water, sanitation, and hygiene (WaSH) interventions. The perceived severity of typhoid and fear of exposure, uncertainty about the effectiveness of WaSH measures, and widespread belief in the efficacy of vaccines in preventing disease resulted in an overwhelming interest in receiving typhoid vaccine during an outbreak.

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Section: Introductionmentioning

confidence: 99%

Formative Investigation of Acceptability of Typhoid Vaccine During a Typhoid Fever Outbreak in Neno District, Malawi

Blum¹,

Dentz²,

Chingoli³

et al. 2014

The American Journal of Tropical Medicine and Hygiene

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“…Processing of zwitterionic capsular polysaccharides by an MHC II pathway has very recently been suggested (Cobb et al 2004). (Acharya et al 1987, Yang et al 2001. Vaccines containing two (Groups A and C), three (Groups A, C and W135) or four meningococcal (Groups A, C, Y and W135) CPSs are licensed.…”

mentioning

confidence: 99%

Vaccines based on the cell surface carbohydrates of pathogenic bacteria

Jones

2005

An. Acad. Bras. Ciênc.

167

117

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Glycoconjugate vaccines, in which a cell surface carbohydrate from a micro-organism is covalently attached to an appropriate carrier protein are proving to be the most effective means to generate protective immune responses to prevent a wide range of diseases. The technology appears to be generic and applicable to a wide range of pathogens, as long as antibodies against surface carbohydrates help protect against infection. Three such vaccines, against Haemophilus influenzae type b, Neisseria meningitidis Group C and seven serotypes of Streptococcus pneumoniae, have already been licensed and many others are in development.This article discusses the rationale for the development and use of glycoconjugate vaccines, the mechanisms by which they elicit T cell-dependent immune responses and the implications of this for vaccine development, the role of physicochemical methods in the characterisation and quality control of these vaccines, and the novel products which are under development.

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“…Earlier, the vaccines were given in multiple doses which were accompanied by adverse reactions. Now, due to the implementation of proper water and sanitation management, formulation of safe vaccines with simple doses [76] and mass awareness of such vaccinations programs have let to successful control in typhoid endemic countries [3,78].…”

Section: Vaccinesmentioning

confidence: 99%

Vi antigen of Salmonella enetrica serovar Typhi — biosynthesis, regulation and its use as vaccine candidate

Kaur

Jain

2012

Open Life Sciences

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Vi capsular polysaccharide (Vi antigen) was first identified as the virulence antigen of Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever in humans. The presence of Vi antigen differentiates S. Typhi from other serovars of Salmonella. Vi antigen is a linear polymer consisting of α-1,4-linked-N-acetyl-galactosaminuronate, whose expression is controlled by three chromosomal loci, namely viaA, viaB and ompB. Both viaA and viaB region are present on Salmonella Pathogenicity Island-7, a large, mosaic, genetic island. The viaA region encodes a positive regulator and the viaB locus is composed of 11 genes designated tviA-tviE (for Vi biosyhthesis), vexA-vexE (for Vi antigen export) and ORF 11. Vi polysaccharide is synthesized from UDP-N-acetyl glucosamine in a series of steps requiring TviB, TviC, and TviE, and regulation of Vi polysaccharide synthesis is controlled by two regulatory systems, rscB-rscC (viaA locus) and ompR-envZ (ompB locus), which respond to changes in osmolarity. This antigen is highly immunogenic and has been used for the formulation of one of the currently available vaccines against typhoid. Despite advancement in the area of vaccinology, its pace of progress needs to be accelerated and effective control programmes will be needed for proper disease management.

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An Outbreak of Typhoid Fever, Xing‐An County, People's Republic of China, 1999: Estimation of the Field Effectiveness of Vi Polysaccharide Typhoid Vaccine

Cited by 49 publications

References 32 publications

Formative Investigation of Acceptability of Typhoid Vaccine During a Typhoid Fever Outbreak in Neno District, Malawi

Formative Investigation of Acceptability of Typhoid Vaccine During a Typhoid Fever Outbreak in Neno District, Malawi

Vaccines based on the cell surface carbohydrates of pathogenic bacteria

Vi antigen of Salmonella enetrica serovar Typhi — biosynthesis, regulation and its use as vaccine candidate

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