Evidence map›Paper›PMID 40318346›Full record

ArticleVaccine2025

Consultation report - considerations for a regulatory pathway for bivalent Salmonella Typhi/Paratyphi A vaccines for use in endemic countries.

Ana Belen Ibarz-Pavon, Marie-Christine Bielsky, Rubina Bose, Marco Cavaleri, John A Crump, Joachim Hombach, David C Kaslow, Farhana Khaman, Calman A MacLennan, Kirsty Mehring-LeDoare and 4 more

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Vaccine, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed.

  1. Review
  2. Article
  3. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

14 authors.

Ana Belen Ibarz-PavonWorld Health Organization, Department of Immunization, Vaccines and Biologicals, Geneva, Switzerland. Electronic address: ibarza@who.int.
Marie-Christine BielskyMedicines and Healthcare products Regulatory Agency (MHRA), London, UK.
Rubina BoseCentral Drugs Standard Control Organization (CDSCO), India.
Marco CavaleriEuropean Medicines Agency, Netherlands.
John A CrumpCentre for International Health, University of Otago, Dunedin, New Zealand.
Joachim HombachWorld Health Organization, Department of Immunization, Vaccines and Biologicals, Geneva, Switzerland.
David C KaslowFood and Drug Administration, Center for Biologics Evaluation and Research, Silver Spring, MD, USA.
Farhana KhamanInternational Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
Calman A MacLennanBill & Melinda Gates Foundation, Enteric & Diarrheal Diseases, 440 5th Ave N, Seattle, WA 98109, USA; Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
Kirsty Mehring-LeDoareWorld Health Organization, Department of Immunization, Vaccines and Biologicals, Geneva, Switzerland; City St. George's, University of London, London, UK.
Andrew J PollardOxford Vaccine Group, Department of Paediatrics, University of Oxford, and The NIHR Oxford Biomedical Research Centre, Oxford, UK.
Firdausi QuadriInternational Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
Jacob JohnChristian Medical College, Vellore, India.
Annelies Wilder-SmithWorld Health Organization, Department of Immunization, Vaccines and Biologicals, Geneva, Switzerland.

Funding

World Health Organization 001
6 · The paper itself

Abstract

Enteric fever caused by Salmonella enterica serovars Typhi and Paratyphi A and, to a lesser extent, S. Paratyphi B and C, remains a significant cause of mortality and morbidity in resource-constrained settings. Typhoid conjugate vaccines (TCVs) protect against S. Typhi but no vaccine to date protects against paratyphoid fever. There are several bivalent S. Typhi/Paratyphi A products in development; however, the low incidence of paratyphoid fever in many settings limits the feasibility of phase 3 efficacy studies. Two bivalent vaccines adding the S. Paratyphi A-specific O:2 lipopolysaccharide conjugated to a protein carrier to TCV constructs have successfully completed phase 1 studies and will progress rapidly in their development. The WHO's Product Development for Vaccines Advisory Committee (PDVAC) endorsed a regulatory pathway for a bivalent S. Typhi/Paratyphi A vaccine that contemplates demonstrating protective efficacy against S. Paratyphi A infection in a controlled human infection model (CHIM). Since the use of CHIM data in lieu of phase 3 efficacy studies and to identify markers of immune protection is not yet widely accepted by regulatory bodies, the WHO organized a consultation with vaccine developers, manufacturers, and regulators. The purpose of the meeting was to discuss the feasibility and considerations for the licensure of a bivalent S. Typhi/Paratyphi A vaccine. The aim of the consultation was to gain alignment among key stakeholders and facilitate the pathway to licensure in endemic countries.

Indexed as

Endemic DiseasesParatyphoid FeverSalmonella paratyphi ASalmonella typhiTyphoid FeverTyphoid-Paratyphoid VaccinesAdvisory CommitteesHumansVaccine DevelopmentVaccines, ConjugateWorld Health OrganizationTyphoid-Paratyphoid VaccinesVaccines, ConjugateEnteric feverParatyphoid feverPhase 3 studyRegulatory pathwaySalmonella Paratyphi AVaccines

Identifiers

PMID40318346
PMCPMC12104798

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.