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Investigating Enteric Fever - Salmonella Typhi and Paratyphi Challenge Study

NCT02192008 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 125

Last updated 2022-06-02

No results posted yet for this study

Summary

Enteric fever, an infection characterised by diarrhoea and rash, is most often caused by a bacteria called Salmonella enterica. After ingesting contaminated food or drink, the Salmonellae travel first to the gut, then the bloodstream, from where they can infect other parts of the body. Antibiotics are used to kill the bacteria, but with increasing rates of antibiotic resistance, this treatment is becoming less effective.

Two Salmonella variants, Typhi and Paratyphi, cause over 30 million cases of enteric fever and more than 200,000 deaths per year, mostly in developing countries. While improved hygiene and sanitation should eventually eliminate enteric fever, reduction of the disease burden in the medium term is achievable through effective vaccination.

Vaccines likely to be available for mass vaccination are effective only against those Salmonella strains that bear the Vi polysaccharide capsule protein. Strains that do not have these capsule proteins, or have no capsule, will not be affected by vaccination and could 'fill' the space vacated by the capsulated strains. Indeed, enteric fever caused by S. Paratyphi A which does not carry the Vi protein, has risen during the past decade and accounts for more than half of all cases in some areas. Thus it is important that effective vaccines are available to protect against infection by both capsulated and noncapsulated Salmonella enterica. To develop such vaccines, we need a complete understanding of the human immune response to both types, including the contribution of immunity in the gut and the bloodstream, immune response to bacterial surface proteins, and the role of antibodies. How much cross-protection there is between the types of typhoidal Salmonellae after natural infection or vaccination is not known, but this is critical to vaccine development.

This project aims to fill in the knowledge gaps highlighted, by fully characterising the infection process and immune response in enteric fever.

Conditions

  • Typhoid Fever
  • Paratyphoid Fever

Interventions

BIOLOGICAL

Salmonella Typhi

BIOLOGICAL

Salmonella Paratyphi

Sponsors & Collaborators

  • University of Liverpool

    collaborator OTHER

  • Brigham and Women's Hospital

    collaborator OTHER

  • University of Oxford

    lead OTHER

Principal Investigators

  • Andrew Pollard, FRCPCH, PhD · University of Oxford

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
60 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2014-12-31
Primary Completion
2018-09-22
Completion
2022-05-26

Countries

  • United Kingdom

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT02192008 on ClinicalTrials.gov