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Parkash V, Ashwin H, Dey S, Sadlova J, Vojtkova B, Van Bocxlaer K, Wiggins R, Thompson D, Dey NS, Jaffe CL, Schwartz E, Volf P, Lacey CJN, Layton AM, Kaye PM. Safety and reactogenicity of a controlled human infection model of sand fly-transmitted cutaneous leishmaniasis. Nat Med 2024:10.1038/s41591-024-03146-9. [PMID: 39095597 DOI: 10.1038/s41591-024-03146-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 06/20/2024] [Indexed: 08/04/2024]
Abstract
The leishmaniases are globally important parasitic diseases for which no human vaccines are currently available. To facilitate vaccine development, we conducted an open-label observational study to establish a controlled human infection model (CHIM) of sand fly-transmitted cutaneous leishmaniasis (CL) caused by Leishmania major. Between 24 January and 12 August 2022, we exposed 14 participants to L. major-infected Phlebotomus duboscqi. The primary objective was to demonstrate effectiveness of lesion development (take rate) and safety (absence of CL lesion at 12 months). Secondary and exploratory objectives included rate of lesion development, parasite load and analysis of local immune responses by immunohistology and spatial transcriptomics. Lesion development was terminated by therapeutic biopsy (between days 14 and 42 after bite) in ten participants with clinically compatible lesions, one of which was not confirmed by parasite detection. We estimated an overall take rate for CL development of 64% (9/14). Two of ten participants had one and one of ten participants had two lesion recurrences 4-8 months after biopsy that were treated successfully with cryotherapy. No severe or serious adverse events were recorded, but as expected, scarring due to a combination of CL and the biopsy procedure was evident. All participants were lesion free at >12-month follow-up. We provide the first comprehensive map of immune cell distribution and cytokine/chemokine expression in human CL lesions, revealing discrete immune niches. This CHIM offers opportunities for vaccine candidate selection based on human efficacy data and for a greater understanding of immune-mediated pathology. ClinicalTrials.gov identifier: NCT04512742 .
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Affiliation(s)
- Vivak Parkash
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Helen Ashwin
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Shoumit Dey
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Jovana Sadlova
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Barbora Vojtkova
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Katrien Van Bocxlaer
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
- Skin Research Centre, Hull York Medical School, York, UK
| | - Rebecca Wiggins
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - David Thompson
- York and Scarborough Teaching Hospitals NHS Foundation Trust, York, UK
| | - Nidhi Sharma Dey
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Charles L Jaffe
- Department of Microbiology and Molecular Genetics, Kuvin Center for the Study of Infectious and Tropical Diseases, IMRIC, The Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Eli Schwartz
- Center for Geographic Medicine and Tropical Diseases, Chaim Sheba Medical Center and the School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Charles J N Lacey
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Alison M Layton
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK.
- Skin Research Centre, Hull York Medical School, York, UK.
| | - Paul M Kaye
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK.
- Skin Research Centre, Hull York Medical School, York, UK.
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2
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Naidu A, Garg V, Balakrishnan D, C R V, Sundararajan V, Lulu S S. Systems and Computational Screening identifies SRC and NKIRAS2 as Baseline Correlates of Risk (CoR) for Live Attenuated Oral Typhoid Vaccine (TY21a) associated Protection. Mol Immunol 2024; 169:99-109. [PMID: 38552286 DOI: 10.1016/j.molimm.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 03/01/2024] [Accepted: 03/13/2024] [Indexed: 04/13/2024]
Abstract
AIM We investigated the molecular underpinnings of variation in immune responses to the live attenuated typhoid vaccine (Ty21a) by analyzing the baseline immunological profile. We utilized gene expression datasets obtained from the Gene Expression Omnibus (GEO) database (accession number: GSE100665) before and after immunization. We then employed two distinct computational approaches to identify potential baseline biomarkers associated with responsiveness to the Ty21a vaccine. MAIN METHODS The first pipeline (knowledge-based) involved the retrieval of differentially expressed genes (DEGs), functional enrichment analysis, protein-protein interaction network construction, and topological network analysis of post-immunization datasets before gauging their pre-vaccination expression levels. The second pipeline utilized an unsupervised machine learning algorithm for data-driven feature selection on pre-immunization datasets. Supervised machine-learning classifiers were employed to computationally validate the identified biomarkers. KEY FINDINGS Baseline activation of NKIRAS2 (a negative regulator of NF-kB signalling) and SRC (an adaptor for immune receptor activation) was negatively associated with Ty21a vaccine responsiveness, whereas LOC100134365 exhibited a positive association. The Stochastic Gradient Descent (SGD) algorithm accurately distinguished vaccine responders and non-responders, with 88.8%, 70.3%, and 85.1% accuracy for the three identified genes, respectively. SIGNIFICANCE This dual-pronged novel analytical approach provides a comprehensive comparison between knowledge-based and data-driven methods for the prediction of baseline biomarkers associated with Ty21a vaccine responsiveness. The identified genes shed light on the intricate molecular mechanisms that influence vaccine efficacy from the host perspective while pushing the needle further towards the need for development of precise enteric vaccines and on the importance of pre-immunization screening.
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Affiliation(s)
- Akshayata Naidu
- Integrative Multi Omics Lab, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India
| | - Varin Garg
- Integrative Multi Omics Lab, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India
| | - Deepna Balakrishnan
- Integrative Multi Omics Lab, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India
| | - Vinaya C R
- Integrative Multi Omics Lab, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India
| | - Vino Sundararajan
- Integrative Multi Omics Lab, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India..
| | - Sajitha Lulu S
- Integrative Multi Omics Lab, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India..
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3
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Weyant C, Hooda Y, Munira SJ, Lo NC, Ryckman T, Tanmoy AM, Kanon N, Seidman JC, Garrett D, Saha SK, Goldhaber-Fiebert JD, Saha S, Andrews JR. Cost-effectiveness and public health impact of typhoid conjugate vaccine introduction strategies in Bangladesh. Vaccine 2024; 42:2867-2876. [PMID: 38531727 PMCID: PMC11033679 DOI: 10.1016/j.vaccine.2024.03.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 03/28/2024]
Abstract
PURPOSE Typhoid fever causes substantial morbidity and mortality in Bangladesh. The government of Bangladesh plans to introduce typhoid conjugate vaccines (TCV) in its expanded program on immunization (EPI) schedule. However, the optimal introduction strategy in addition to the costs and benefits of such a program are unclear. METHODS We extended an existing mathematical model of typhoid transmission to integrate cost data, clinical incidence data, and recently conducted serosurveys in urban, semi-urban, and rural areas. In our primary analysis, we evaluated the status quo (i.e., no vaccination) and eight vaccine introduction strategies including routine and 1-time campaign strategies, which differed by age groups targeted and geographic focus. Model outcomes included clinical incidence, seroincidence, deaths, costs, disability-adjusted life years (DALYs), and incremental cost-effectiveness ratios (ICERs) for each strategy. We adopted a societal perspective, 10-year model time horizon, and 3 % annual discount rate. We performed probabilistic, one-way, and scenario sensitivity analyses including adopting a healthcare perspective and alternate model time horizons. RESULTS We projected that all TCV strategies would be cost saving compared to the status quo. The preferred strategy was a nationwide introduction of TCV at 9-12 months of age with a single catch-up campaign for children ages 1-15, which was cost saving compared to all other strategies and the status quo. In the 10 years following implementation, we projected this strategy would avert 3.77 million cases (95 % CrI: 2.60 - 5.18), 11.31 thousand deaths (95 % CrI: 3.77 - 23.60), and save $172.35 million (95 % CrI: -14.29 - 460.59) compared to the status quo. Our findings were broadly robust to changes in parameter values and willingness-to-pay thresholds. CONCLUSIONS We projected that nationwide TCV introduction with a catch-up campaign would substantially reduce typhoid incidence and very likely be cost saving in Bangladesh.
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Affiliation(s)
- Christopher Weyant
- Department of Health Policy and Center for Health Policy, Stanford School of Medicine and Freeman Spogli Institute, Stanford University, Stanford, CA, United States.
| | - Yogesh Hooda
- Child Health Research Foundation, Dhaka, Bangladesh
| | | | - Nathan C Lo
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Theresa Ryckman
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | | | - Naito Kanon
- Child Health Research Foundation, Dhaka, Bangladesh
| | | | | | - Samir K Saha
- Child Health Research Foundation, Dhaka, Bangladesh; Department of Microbiology, Bangladesh Shishu Hospital and Institute, Dhaka, Bangladesh
| | - Jeremy D Goldhaber-Fiebert
- Department of Health Policy and Center for Health Policy, Stanford School of Medicine and Freeman Spogli Institute, Stanford University, Stanford, CA, United States
| | - Senjuti Saha
- Child Health Research Foundation, Dhaka, Bangladesh
| | - Jason R Andrews
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
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Abo YN, Jamrozik E, McCarthy JS, Roestenberg M, Steer AC, Osowicki J. Strategic and scientific contributions of human challenge trials for vaccine development: facts versus fantasy. THE LANCET. INFECTIOUS DISEASES 2023; 23:e533-e546. [PMID: 37573871 DOI: 10.1016/s1473-3099(23)00294-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 08/15/2023]
Abstract
The unprecedented speed of delivery of SARS-CoV-2 pandemic vaccines has redefined the limits for all vaccine development. Beyond the aspirational 100-day timeline for tomorrow's hypothetical pandemic vaccines, there is a sense of optimism that development of other high priority vaccines can be accelerated. Early in the COVID-19 pandemic, an intense and polarised academic and public discourse arose concerning the role of human challenge trials for vaccine development. A case was made for human challenge trials as a powerful tool to establish early proof-of-concept of vaccine efficacy in humans, inform vaccine down selection, and address crucial knowledge gaps regarding transmission, pathogenesis, and immune protection. We review the track record of human challenge trials contributing to the development of vaccines for 19 different pathogens and discuss relevant limitations, barriers, and pitfalls. This Review also highlights opportunities for efforts to broaden the scope and boost the effects of human challenge trials, to accelerate all vaccine development.
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Affiliation(s)
- Yara-Natalie Abo
- Tropical Diseases Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, VIC, Australia.
| | - Euzebiusz Jamrozik
- Ethox and Pandemic Sciences Institute, Nuffield Department of Population Health, University of Oxford, Oxford, UK; Monash-WHO Collaborating Centre for Bioethics, Monash University, Melbourne, VIC, Australia
| | - James S McCarthy
- Department of Infectious Diseases, The University of Melbourne, Parkville, VIC, Australia; Victorian Infectious Diseases Services, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Meta Roestenberg
- Controlled Human Infections Center, Leiden University Medical Center, Leiden, Netherlands
| | - Andrew C Steer
- Tropical Diseases Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, VIC, Australia
| | - Joshua Osowicki
- Tropical Diseases Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, VIC, Australia
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5
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Barton A, Hill J, O'Connor D, Jones C, Jones E, Camara S, Shrestha S, Jin C, Gibani MM, Dobinson HC, Waddington C, Darton TC, Blohmke CJ, Pollard AJ. Early transcriptional responses to human enteric fever challenge. Infect Immun 2023; 91:e0010823. [PMID: 37725060 PMCID: PMC10581002 DOI: 10.1128/iai.00108-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/29/2023] [Indexed: 09/21/2023] Open
Abstract
Enteric fever, caused by oral infection with typhoidal Salmonella serovars, presents as a non-specific febrile illness preceded by an incubation period of 5 days or more. The enteric fever human challenge model provides a unique opportunity to investigate the innate immune response during this incubation period, and how this response is altered by vaccination with the Vi polysaccharide or conjugate vaccine. We find that on the same day as ingestion of typhoidal Salmonella, there is already evidence of an immune response, with 199 genes upregulated in the peripheral blood transcriptome 12 hours post-challenge (false discovery rate <0.05). Gene sets relating to neutrophils, monocytes, and innate immunity were over-represented (false discovery rate <0.05). Estimating cell proportions from gene expression data suggested a possible increase in activated monocytes 12 hours post-challenge (P = 0.036, paired Wilcoxon signed-rank test). Furthermore, plasma TNF-α rose following exposure (P = 0.011, paired Wilcoxon signed-rank test). There were no significant differences in gene expression (false discovery rate <0.05) in the 12 hours response between those who did and did not subsequently develop clinical or blood culture confirmed enteric fever or between vaccination groups. Together, these results demonstrate early perturbation of the peripheral blood transcriptome after enteric fever challenge and provide initial insight into early mechanisms of protection.
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Affiliation(s)
- Amber Barton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Jennifer Hill
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Daniel O'Connor
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Susana Camara
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Sonu Shrestha
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Pathology, Royal Melbourne Hospital, Melbourne, Australia
- Infectious Diseases and Immune Defence Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Malick M. Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Hazel C. Dobinson
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Claire Waddington
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Infectious Disease, Imperial College, London, United Kingdom
| | - Thomas C. Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Infection, Immunity and Cardiovascular Disease and The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Christoph J. Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Andrew J. Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
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6
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Smith C, Smith E, Chiu C, Hinton J, Perez Sepulveda B, Gordon M, Choy RK, Hill PW, Meiring JE, Darton TC, Carey ME, Cooke G, Gibani MM. The Challenge Non-Typhoidal Salmonella (CHANTS) Consortium: Development of a non-typhoidal Salmonella controlled human infection model: Report from a consultation group workshop, 05 July 2022, London, UK. Wellcome Open Res 2023; 8:111. [PMID: 37808389 PMCID: PMC10558987 DOI: 10.12688/wellcomeopenres.19012.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2023] [Indexed: 10/10/2023] Open
Abstract
Invasive non-typhoidal Salmonella disease (iNTS) is a major cause of morbidity and mortality globally, particularly as a cause of bloodstream infection in children and immunocompromised adults in sub-Saharan Africa. Vaccines to prevent non-typhoidal Salmonella (NTS) would represent a valuable public health tool in this setting to avert cases and prevent expansion of antimicrobial resistance. Several NTS and combination typhoidal-NTS vaccine candidates are in early-stage development, although the pathway to licensure is unclear due to challenges in conducting large phase III field trials. Controlled human infection models (CHIM) present an opportunity to accelerate vaccine development for a range of enteric pathogens. Several recent typhoidal Salmonella CHIMs have been conducted safely and have played pivotal roles in progressing vaccine candidates to pre-qualification and licensure. The Challenge Non-Typhoidal Salmonella (CHANTS) consortium has been formed with funding from the Wellcome Trust, to deliver the first NTS CHIM, which can act as a platform for future vaccine evaluation. This paper reports the conclusions of a consultation group workshop convened with key stakeholders. The aims of this meeting were to: (1) define the rationale for an NTS CHIM (2) map the NTS vaccine pipeline (3) refine study design and (4) establish potential future use cases.
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Affiliation(s)
- Christopher Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Emma Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Christopher Chiu
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Jay Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Blanca Perez Sepulveda
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Melita Gordon
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - Peter W.S. Hill
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - James E. Meiring
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Thomas C. Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Megan E. Carey
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Graham Cooke
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Malick M. Gibani
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - CHANTS Consortium
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- PATH, Seattle, Washington, 98121, USA
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
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7
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Smith C, Smith E, Chiu C, Hinton J, Perez Sepulveda B, Gordon M, Choy RK, Hill PW, Meiring JE, Darton TC, Carey ME, Cooke G, Gibani MM. The Challenge Non-Typhoidal Salmonella (CHANTS) Consortium: Development of a non-typhoidal Salmonella controlled human infection model: Report from a consultation group workshop, 05 July 2022, London, UK. Wellcome Open Res 2023; 8:111. [PMID: 37808389 PMCID: PMC10558987 DOI: 10.12688/wellcomeopenres.19012.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2023] [Indexed: 04/21/2024] Open
Abstract
Invasive non-typhoidal Salmonella disease (iNTS) is a major cause of morbidity and mortality globally, particularly as a cause of bloodstream infection in children and immunocompromised adults in sub-Saharan Africa. Vaccines to prevent non-typhoidal Salmonella (NTS) would represent a valuable public health tool in this setting to avert cases and prevent expansion of antimicrobial resistance. Several NTS and combination typhoidal-NTS vaccine candidates are in early-stage development, although the pathway to licensure is unclear due to challenges in conducting large phase III field trials. Controlled human infection models (CHIM) present an opportunity to accelerate vaccine development for a range of enteric pathogens. Several recent typhoidal Salmonella CHIMs have been conducted safely and have played pivotal roles in progressing vaccine candidates to pre-qualification and licensure. The Challenge Non-Typhoidal Salmonella (CHANTS) consortium has been formed with funding from the Wellcome Trust, to deliver the first NTS CHIM, which can act as a platform for future vaccine evaluation. This paper reports the conclusions of a consultation group workshop convened with key stakeholders. The aims of this meeting were to: (1) define the rationale for an NTS CHIM (2) map the NTS vaccine pipeline (3) refine study design and (4) establish potential future use cases.
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Affiliation(s)
- Christopher Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Emma Smith
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Christopher Chiu
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Jay Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Blanca Perez Sepulveda
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Melita Gordon
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - Peter W.S. Hill
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - James E. Meiring
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Thomas C. Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
| | - Megan E. Carey
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Graham Cooke
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - Malick M. Gibani
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
| | - CHANTS Consortium
- Department of Infectious Disease, Imperial College London, London, W2 1PG, UK
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- PATH, Seattle, Washington, 98121, USA
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, S10 2TN, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
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8
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Das S, Howlader DR, Lu T, Whittier SK, Hu G, Sharma S, Dietz ZK, Ratnakaram SSK, Varisco DJ, Ernst RK, Picking WD, Picking WL. Immunogenicity and protective efficacy of nanoparticle formulations of L-SseB against Salmonella infection. Front Immunol 2023; 14:1208848. [PMID: 37457702 PMCID: PMC10347375 DOI: 10.3389/fimmu.2023.1208848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 06/13/2023] [Indexed: 07/18/2023] Open
Abstract
Salmonella enterica, a Gram-negative pathogen, has over 2500 serovars that infect a wide range of hosts. In humans, S. enterica causes typhoid or gastroenteritis and is a major public health concern. In this study, SseB (the tip protein of the Salmonella pathogenicity island 2 type III secretion system) was fused with the LTA1 subunit of labile-toxin from enterotoxigenic E. coli to make the self-adjuvanting antigen L-SseB. Two unique nanoparticle formulations were developed to allow multimeric presentation of L-SseB. Mice were vaccinated with these formulations and protective efficacy determined via challenging the mice with S. enterica serovars. The polysaccharide (chitosan) formulation was found to elicit better protection when compared to the squalene nanoemulsion. When the polysaccharide formulation was used to vaccinate rabbits, protection from S. enterica challenge was elicited. In summary, L-SseB in a particulate polysaccharide formulation appears to be an attractive candidate vaccine capable of broad protection against S. enterica.
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Affiliation(s)
- Sayan Das
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Debaki R. Howlader
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Ti Lu
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Sean K. Whittier
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Gang Hu
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Simran Sharma
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO, United States
| | - Zackary K. Dietz
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Siva S. K. Ratnakaram
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - David J. Varisco
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States
| | - William D. Picking
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Wendy L. Picking
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
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9
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McCann N, Emary K, Singh N, Mclean F, Camara S, Jones E, Kim YC, Liu X, Greenland M, Conlin K, Hill J, Verheul M, Robinson H, Angus B, Ramasamy MN, Levine MM, Pollard AJ. Accelerating clinical development of a live attenuated vaccine against Salmonella Paratyphi A (VASP): study protocol for an observer-participant-blind randomised control trial of a novel oral vaccine using a human challenge model of Salmonella Paratyphi A infection in healthy adult volunteers. BMJ Open 2023; 13:e068966. [PMID: 37225278 DOI: 10.1136/bmjopen-2022-068966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
INTRODUCTION This is the first efficacy study of an oral live attenuated vaccine against Salmonella Paratyphi A using a human challenge model of paratyphoid infection. S. Paratyphi A is responsible for 3.3 million cases of enteric fever every year, with over 19 000 deaths. Although improvements to sanitation and access to clean water are vital to reduce the burden of this condition, vaccination offers a cost-effective, medium-term solution. Efficacy trials of potential S. Paratyphi vaccine candidates in the field are unlikely to be feasible given the large number of participants required. Human challenge models therefore offer a unique, cost-effective solution to test efficacy of such vaccines. METHODS AND ANALYSIS This is an observer-blind, randomised, placebo-controlled trial phase I/II of the oral live-attenuated vaccine against S. Paratyphi A, CVD 1902. Volunteers will be randomised 1:1 to receive two doses of CVD 1902 or placebo, 14 days apart. One month following second vaccination all volunteers will ingest S. Paratyphi A bacteria with a bicarbonate buffer solution. They will be reviewed daily in the following 14 days and diagnosed with paratyphoid infection if the predefined microbiological or clinical diagnostic criteria are met. All participants will be treated with antibiotics on diagnosis, or at day 14 postchallenge if not diagnosed. The vaccine efficacy will be determined by comparing the relative attack rate, that is, the proportion of those diagnosed with paratyphoid infection, in the vaccine and placebo groups. ETHICS AND DISSEMINATION Ethical approval for this study has been obtained from the Berkshire Medical Research Ethics Committee (REC ref 21/SC/0330). The results will be disseminated via publication in a peer-reviewed journal and presentation at international conferences. TRIAL REGISTRATION NUMBER ISRCTN15485902.
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Affiliation(s)
- Naina McCann
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Katherine Emary
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Nisha Singh
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Florence Mclean
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Susana Camara
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Elizabeth Jones
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Young Chan Kim
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Xinxue Liu
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Melanie Greenland
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Kerry Conlin
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Jennifer Hill
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Marije Verheul
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Hannah Robinson
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Brian Angus
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Maheshi N Ramasamy
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Myron M Levine
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Andrew J Pollard
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
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10
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Costanzo V, Roviello GN. The Potential Role of Vaccines in Preventing Antimicrobial Resistance (AMR): An Update and Future Perspectives. Vaccines (Basel) 2023; 11:vaccines11020333. [PMID: 36851210 PMCID: PMC9962013 DOI: 10.3390/vaccines11020333] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 01/23/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
In the modern era, the consumption of antibiotics represents a revolutionary weapon against several infectious diseases, contributing to the saving of millions of lives worldwide. However, the misuse of antibiotics for human and animal purposes has fueled the process of antimicrobial resistance (AMR), considered now a global emergency by the World Health Organization (WHO), which significantly increases the mortality risk and related medical costs linked to the management of bacterial diseases. The current research aiming at developing novel efficient antibiotics is very challenging, and just a few candidates have been identified so far due to the difficulties connected with AMR. Therefore, novel therapeutic or prophylactic strategies to fight AMR are urgently needed. In this scenario, vaccines constitute a promising approach that proves to be crucial in preventing pathogen spreading in primary infections and in minimizing the usage of antibiotics following secondary bacterial infections. Unfortunately, most of the vaccines developed against the main resistant pathogens are still under preclinical and clinical evaluation due to the complexity of pathogens and technical difficulties. In this review, we describe not only the main causes of AMR and the role of vaccines in reducing the burden of infectious diseases, but we also report on specific prophylactic advancements against some of the main pathogens, focusing on new strategies that aim at improving vaccine efficiency.
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Affiliation(s)
- Vincenzo Costanzo
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna Alma Mater Studiorum, 40126 Bologna, Italy
- Correspondence: (V.C.); (G.N.R.)
| | - Giovanni N. Roviello
- Italian National Council for Research (IBB-CNR), Area di Ricerca site and Headquartes, Via Pietro Castellino 111, 80131 Naples, Italy
- Correspondence: (V.C.); (G.N.R.)
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11
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A Familiar Outbreak of Monophasic Salmonella serovar Typhimurium (ST34) Involving Three Dogs and Their Owner's Children. Pathogens 2022; 11:pathogens11121500. [PMID: 36558834 PMCID: PMC9788015 DOI: 10.3390/pathogens11121500] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/23/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Salmonella is a Gram-negative enteric bacterium responsible for the foodborne and waterborne disease salmonellosis, which is the second most reported bacterial zoonosis in humans. Many animals are potential sources of salmonellosis, including dogs, cats, and other pets. We report the case of an outbreak of salmonellosis in a family in central Italy, affecting two children and involving their three dogs as carriers. One of the children needed medical care and hospitalisation. Isolation and analysis of stool samples from the sibling and the animals present in the house were carried out. Serotyping allowed the identification of S. enterica subsp. enterica serovar Typhimurium in its monophasic variant for all the isolates. The results of whole-genome sequencing confirmed that the strains were tightly related. The minimum inhibitory concentration (MIC) test documented the resistance to ampicillin, sulfamethoxazole, and tetracycline. The origin of the zoonotic outbreak could not be assessed; however, the case study showed a clear passage of the pathogen between the human and non-human members of the family. The possibility of a transmission from a dog to a human suggests the need for further studies on the potential ways of transmission of salmonellosis through standard and alternative feed.
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12
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Sztein MB, Booth JS. Controlled human infectious models, a path forward in uncovering immunological correlates of protection: Lessons from enteric fevers studies. Front Microbiol 2022; 13:983403. [PMID: 36204615 PMCID: PMC9530043 DOI: 10.3389/fmicb.2022.983403] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Enteric infectious diseases account for more than a billion disease episodes yearly worldwide resulting in approximately 2 million deaths, with children under 5 years old and the elderly being disproportionally affected. Enteric pathogens comprise viruses, parasites, and bacteria; the latter including pathogens such as Salmonella [typhoidal (TS) and non-typhoidal (nTS)], cholera, Shigella and multiple pathotypes of Escherichia coli (E. coli). In addition, multi-drug resistant and extensively drug-resistant (XDR) strains (e.g., S. Typhi H58 strain) of enteric bacteria are emerging; thus, renewed efforts to tackle enteric diseases are required. Many of these entero-pathogens could be controlled by oral or parenteral vaccines; however, development of new, effective vaccines has been hampered by lack of known immunological correlates of protection (CoP) and limited knowledge of the factors contributing to protective responses. To fully comprehend the human response to enteric infections, an invaluable tool that has recently re-emerged is the use of controlled human infection models (CHIMs) in which participants are challenged with virulent wild-type (wt) organisms. CHIMs have the potential to uncover immune mechanisms and identify CoP to enteric pathogens, as well as to evaluate the efficacy of therapeutics and vaccines in humans. CHIMs have been used to provide invaluable insights in the pathogenesis, host-pathogen interaction and evaluation of vaccines. Recently, several Oxford typhoid CHIM studies have been performed to assess the role of multiple cell types (B cells, CD8+ T, Tregs, MAIT, Monocytes and DC) during S. Typhi infection. One of the key messages that emerged from these studies is that baseline antigen-specific responses are important in that they can correlate with clinical outcomes. Additionally, volunteers who develop typhoid disease (TD) exhibit higher levels and more activated cell types (e.g., DC and monocytes) which are nevertheless defective in discrete signaling pathways. Future critical aspects of this research will involve the study of immune responses to enteric infections at the site of entry, i.e., the intestinal mucosa. This review will describe our current knowledge of immunity to enteric fevers caused byS. Typhi and S. Paratyphi A, with emphasis on the contributions of CHIMs to uncover the complex immunological responses to these organisms and provide insights into the determinants of protective immunity.
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Affiliation(s)
- Marcelo B. Sztein
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: Marcelo B. Sztein,
| | - Jayaum S. Booth
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
- Jayaum S. Booth,
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13
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Honda-Okubo Y, Cartee RT, Thanawastien A, Seung Yang J, Killeen KP, Petrovsky N. A typhoid fever protein capsular matrix vaccine candidate formulated with Advax-CpG adjuvant induces a robust and durable anti-typhoid Vi polysaccharide antibody response in mice, rabbits and nonhuman primates. Vaccine 2022; 40:4625-4634. [PMID: 35750538 DOI: 10.1016/j.vaccine.2022.06.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 10/17/2022]
Abstract
Typhax is an investigational typhoid fever vaccine candidate that is comprised of Vi polysaccharide from Salmonella enterica serovar typhi (S. Typhi) non-covalently entrapped in a glutaraldehyde catalyzed, cross-linked α-poly-L-lysine and CRM197 protein matrix. A previous Phase 1 trial of an aluminum phosphate adjuvanted Typhax formulation showed it induced Vi IgG after a single dose but that subsequent doses failed to further boost Vi IgG levels. The current study asked whether Advax-CpG adjuvant might instead be able to overcome polysaccharide-induced immune inhibition and improve Typhax immunogenicity. Advax-CpG adjuvanted Typhax elicited high and sustained Vi IgG responses in mice, rabbits and non-human primates (NHP) with levels being boosted by repeated immunization. High Vi antibody responses were lost in CD4 + T cell depleted mice confirming that despite the lack of conjugation of the polysaccharide to the carrier protein, Typhax nevertheless acts in a T cell dependent manner, explaining its ability to induce long-term B cell memory responses to Vi capable of being boosted. In NHP, Advax-CpG adjuvanted Typhax induced up to 100-fold higher Vi IgG levels than the commercial Typhim Vi polysaccharide vaccine. Typhax induced high and sustained serum bactericidal activity against S. Typhi and stimulated robust Vi IgG responses even in animals previously primed with a pure polysaccharide vaccine. Hence Advax-CpG adjuvanted Typhax vaccine is a highly promising candidate to provide robust and durable protection against typhoid fever.
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Affiliation(s)
- Yoshikazu Honda-Okubo
- Vaxine Pty Ltd, 11 Walkley Avenue, Warradale, Adelaide, Australia; School of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Robert T Cartee
- Matrivax Research & Development Corporation, Boston, MA, USA
| | | | - Jae Seung Yang
- Clinical Immunology, International Vaccine Institute (IVI), South Korea
| | - Kevin P Killeen
- Matrivax Research & Development Corporation, Boston, MA, USA
| | - Nikolai Petrovsky
- Vaxine Pty Ltd, 11 Walkley Avenue, Warradale, Adelaide, Australia; School of Medicine and Public Health, Flinders University, Adelaide, Australia.
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14
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Oxford JS, Catchpole A, Mann A, Bell A, Noulin N, Gill D, Oxford JR, Gilbert A, Balasingam S. A Brief History of Human Challenge Studies (1900-2021) Emphasising the Virology, Regulatory and Ethical Requirements, Raison D'etre, Ethnography, Selection of Volunteers and Unit Design. Curr Top Microbiol Immunol 2022. [PMID: 35704095 DOI: 10.1007/82_2022_253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Venetian quarantine 400 years ago was an important public health measure. Since 1900 this has been refined to include "challenge" or deliberate infection with pathogens be they viruses, bacteria, or parasites. Our focus is virology and ranges from the early experiments in Cuba with Yellow Fever Virus to the most widespread pathogen of our current times, COVID-19. The latter has so far caused over four million deaths worldwide and 190 million cases of the disease. Quarantine and challenge were also used to investigate the Spanish Influenza of 1918 which caused over 100 million deaths. We consider here the merits of the approach, that is the speeding up of knowledge in a practical sense leading to the more rapid licensing of vaccines and antimicrobials. At the core of quarantine and challenge initiatives is the design of the unit to allow safe confinement of the pathogen and protection of the staff. Most important though is the safety of volunteers. We can see now, as in 1900, that members of our society are prepared and willing to engage in these experiments for the public good. Our ethnology study, where the investigator observed the experiment from within the quarantine, gave us the first indication of changing attitudes amongst volunteers whilst in quarantine. These quarantine experiments, referred to as challenge studies, human infection studies, or "controlled human infection models" involve thousands of clinical samples taken over two to three weeks and can provide a wealth of immunological and molecular data on the infection itself and could allow the discovery of new targets for vaccines and therapeutics. The Yellow Fever studies from 121 years ago gave the impetus for development of a successful vaccine still used today whilst also uncovering the nature of the Yellow Fever agent, namely that it was a virus. We outline how carefully these experiments are approached and the necessity to have high quality units with self-contained air-flow along with extensive personal protective equipment for nursing and medical staff. Most important is the employment of highly trained scientific, medical and nursing staff. We face a future of emerging pathogens driven by the increasing global population, deforestation, climate change, antibiotic resistance and increased global travel. These emerging pathogens may be pathogens we currently are not aware of or have not caused outbreaks historically but could also be mutated forms of known pathogens including viruses such as influenza (H7N9, H5N1 etc.) and coronaviruses. This calls for challenge studies to be part of future pandemic preparedness as an additional tool to assist with the rapid development of broad-spectrum antimicrobials, immunomodulators and new vaccines.
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Affiliation(s)
- J S Oxford
- Blizzard Institute of Cell and Molecular Science, Queen Mary University of London, London, E1 2AT, UK
| | | | | | | | | | - D Gill
- Blizzard Institute of Cell and Molecular Science, Queen Mary University of London, London, E1 2AT, UK
| | - J R Oxford
- Inveresk Medical Practice, Edinburgh, E21 7BP, UK
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15
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Clarkson KA, Porter CK, Talaat KR, Kapulu MC, Chen WH, Frenck RW, Bourgeois AL, Kaminski RW, Martin LB. Shigella-Controlled Human Infection Models: Current and Future Perspectives. Curr Top Microbiol Immunol 2022. [PMID: 35616717 DOI: 10.1007/82_2021_248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Shigella-controlled human infection models (CHIMs) are an invaluable tool utilized by the vaccine community to combat one of the leading global causes of infectious diarrhea, which affects infants, children and adults regardless of socioeconomic status. The impact of shigellosis disproportionately affects children in low- and middle-income countries (LMICs) resulting in cognitive and physical stunting, perpetuating a cycle that must be halted. Shigella-CHIMs not only facilitate the early evaluation of enteric countermeasures and up-selection of the most promising products but also provide insight into mechanisms of infection and immunity that are not possible utilizing animal models or in vitro systems. The greater understanding of shigellosis obtained in CHIMs builds and empowers the development of new generation solutions to global health issues which are unattainable in the conventional laboratory and clinical settings. Therefore, refining, mining and expansion of safe and reproducible infection models hold the potential to create effective means to end diarrheal disease and associated co-morbidities associated with Shigella infection.
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Affiliation(s)
- Kristen A Clarkson
- Department of Diarrheal Disease Research, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
| | - Chad K Porter
- Enteric Disease Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
| | - Kawsar R Talaat
- Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, 624 North Broadway Street Hampton House, Baltimore, MD, 21205, USA
| | - Melissa C Kapulu
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi County Hospital, Off Bofa Road, Kilifi, 80108, Kenya
| | - Wilbur H Chen
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD, 21201, USA
| | - Robert W Frenck
- Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - A Louis Bourgeois
- PATH Center for Vaccine Innovation and Access, 455 Massachusetts Avenue NW, Washington, DC, 20001, USA
| | - Robert W Kaminski
- Department of Diarrheal Disease Research, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
| | - Laura B Martin
- GSK Vaccines Institute for Global Health, Via Fiorentina 1, 53100, Siena, Italy.
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MacLennan CA. The Background, Role and Approach for Development of a Controlled Human Infection Model for Nontyphoidal Salmonella. Curr Top Microbiol Immunol 2021. [PMID: 34958419 DOI: 10.1007/82_2021_246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nontyphoidal Salmonella (NTS) is responsible for a major global burden of disease and economic loss, particularly in low- and middle-income countries. It is designated a priority pathogen by the WHO for vaccine development and, with new impetus from vaccine developers, the establishment of an NTS controlled human infection model (CHIM) is timely and valuable. The broadly dichotomous clinical presentations of diarrhoea and invasive disease, commonly bacteraemia, present significant challenges to the development of an NTS CHIM. Nevertheless, if successful, such a CHIM will be invaluable for understanding the pathogenesis of NTS disease, identifying correlates of protection and advancing candidate vaccines towards licensure. This article describes the background case for a CHIM for NTS, the role of such a CHIM and outlines a potential approach to its development.
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Affiliation(s)
- Calman A MacLennan
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK.
- Bill & Melinda Gates Foundation, 62 Buckingham Gate, London, SW16AJ, UK.
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17
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Ryckman T, Karthikeyan AS, Kumar D, Cao Y, Kang G, Goldhaber-Fiebert JD, John J, Lo NC, Andrews JR. Comparison of Strategies for Typhoid Conjugate Vaccine Introduction in India: A Cost-Effectiveness Modeling Study. J Infect Dis 2021; 224:S612-S624. [PMID: 35238367 PMCID: PMC8892534 DOI: 10.1093/infdis/jiab150] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Typhoid fever causes substantial global mortality, with almost half occurring in India. New typhoid vaccines are highly effective and recommended by the World Health Organization for high-burden settings. There is a need to determine whether and which typhoid vaccine strategies should be implemented in India. Methods We assessed typhoid vaccination using a dynamic compartmental model, parameterized by and calibrated to disease and costing data from a recent multisite surveillance study in India. We modeled routine and 1-time campaign strategies that target different ages and settings. The primary outcome was cost-effectiveness, measured by incremental cost-effectiveness ratios (ICERs) benchmarked against India’s gross national income per capita (US$2130). Results Both routine and campaign vaccination strategies were cost-saving compared to the status quo, due to averted costs of illness. The preferred strategy was a nationwide community-based catchup campaign targeting children aged 1–15 years alongside routine vaccination, with an ICER of $929 per disability-adjusted life-year averted. Over the first 10 years of implementation, vaccination could avert 21–39 million cases and save $1.6–$2.2 billion. These findings were broadly consistent across willingness-to-pay thresholds, epidemiologic settings, and model input distributions. Conclusions Despite high initial costs, routine and campaign typhoid vaccination in India could substantially reduce mortality and was highly cost-effective.
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Affiliation(s)
- Theresa Ryckman
- Stanford Health Policy, Center for Health Policy and Center for Primary Care and Outcomes Research, Stanford University School of Medicine and the Freeman Spogli Institute, Stanford, California, USA
| | - Arun S Karthikeyan
- Wellcome Trust Research Laboratory, Christian Medical College, Vellore, Tamil Nadu, India
| | - Dilesh Kumar
- Wellcome Trust Research Laboratory, Christian Medical College, Vellore, Tamil Nadu, India
| | - Yanjia Cao
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Gagandeep Kang
- Wellcome Trust Research Laboratory, Christian Medical College, Vellore, Tamil Nadu, India
| | - Jeremy D Goldhaber-Fiebert
- Stanford Health Policy, Center for Health Policy and Center for Primary Care and Outcomes Research, Stanford University School of Medicine and the Freeman Spogli Institute, Stanford, California, USA
| | - Jacob John
- Department of Community Health, Christian Medical College, Vellore, Tamil Nadu, India
| | - Nathan C Lo
- Department of Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Jason R Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, USA
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Batool R, Tahir Yousafzai M, Qureshi S, Ali M, Sadaf T, Mehmood J, Ashorn P, Naz Qamar F. Effectiveness of typhoid conjugate vaccine against culture-confirmed typhoid in a peri-urban setting in Karachi: A case-control study. Vaccine 2021; 39:5858-5865. [PMID: 34465474 DOI: 10.1016/j.vaccine.2021.08.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/23/2021] [Accepted: 08/12/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND Enteric fever, caused by Salmonella Typhi and S. Paratyphi, is a cause of high morbidity and mortality among children in South Asia. Rising antimicrobial resistance presents an additional challenge. Typhoid Conjugate Vaccines (TCV) are recommended by the World Health Organization for use among people 6 months to 45 years old living in endemic settings. This study aimed to assess the effectiveness of TCV against culture-confirmed S. Typhi in Lyari Town, Karachi, Pakistan. This peri-urban town was one of the worst affected by the outbreak of extensively drug resistant (XDR) typhoid that started in November 2016. METHODS A matched case-control study was conducted following a mass immunization campaign with TCV at three key hospitals in Lyari Town Karachi, Pakistan. Children aged 6 months to 15 years presenting with culture-confirmed S. Typhi were enrolled as cases. For each case, at least 1 age-matched hospital control and two age-matched community controls were enrolled. Adjusted odds ratios with 95% confidence intervals (CIs) were calculated using conditional logistic regression. RESULTS Of 82 typhoid fever patients enrolled from August 2019 through December 2019, 8 (9·8%) had received vaccine for typhoid. Of the 164 community controls and 82 hospital controls enrolled, 38 (23·2%) community controls and 27 (32·9%) hospital controls were vaccinated for typhoid. The age and sex-adjusted vaccine effectiveness was found to be 72% (95% CI: 34% - 88%). The consumption of meals prepared outside home more than once per month (adjusted odds ratio: 3·72, 95% CI: 1·55- 8·94; p-value: 0·003) was associated with the development of culture-confirmed typhoid. CONCLUSION A single dose of TCV is effective against culture confirmed typhoid among children aged 6 months to 15 years old in an XDR typhoid outbreak setting of a peri-urban community in Karachi, Pakistan.
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Affiliation(s)
- Rabab Batool
- Department of Pediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Aga Khan University Hospital, Karachi City, Sindh 74800, Pakistan; Adolescent, and Maternal Health, Faculty of Medicine and Health Technology, Tampere University, Kalevantie 4, 33100 Tampere, Finland.
| | - Mohammad Tahir Yousafzai
- Department of Pediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Aga Khan University Hospital, Karachi City, Sindh 74800, Pakistan; Kirby Institute, University of New South Wales, Level 6, Wallace Wurth Building, High Street, Kensington, NSW 2052, Australia.
| | - Sonia Qureshi
- Department of Pediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Aga Khan University Hospital, Karachi City, Sindh 74800, Pakistan.
| | - Miqdad Ali
- Department of Pediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Aga Khan University Hospital, Karachi City, Sindh 74800, Pakistan.
| | - Tahira Sadaf
- Department of Pediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Aga Khan University Hospital, Karachi City, Sindh 74800, Pakistan.
| | - Junaid Mehmood
- Department of Pediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Aga Khan University Hospital, Karachi City, Sindh 74800, Pakistan.
| | - Per Ashorn
- Adolescent, and Maternal Health, Faculty of Medicine and Health Technology, Tampere University, Kalevantie 4, 33100 Tampere, Finland; Department of Paediatrics, Tampere University Hospital, Kalevantie 4, 33100 Tampere, Finland.
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Aga Khan University Hospital, Karachi City, Sindh 74800, Pakistan.
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Soulier A, Prevosto C, Chol M, Deban L, Cranenburgh RM. Engineering a Novel Bivalent Oral Vaccine against Enteric Fever. Int J Mol Sci 2021; 22:ijms22063287. [PMID: 33807097 PMCID: PMC8005139 DOI: 10.3390/ijms22063287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/18/2021] [Accepted: 03/21/2021] [Indexed: 11/25/2022] Open
Abstract
Enteric fever is a major global healthcare issue caused largely by Salmonella enterica serovars Typhi and Paratyphi A. The objective of this study was to develop a novel, bivalent oral vaccine capable of protecting against both serovars. Our approach centred on genetically engineering the attenuated S. Typhi ZH9 strain, which has an excellent safety record in clinical trials, to introduce two S. Paratyphi A immunogenic elements: flagellin H:a and lipopolysaccharide (LPS) O:2. We first replaced the native S. Typhi fliC gene encoding flagellin with the highly homologous fliC gene from S. Paratyphi A using Xer-cise technology. Next, we replaced the S. Typhi rfbE gene encoding tyvelose epimerase with a spacer sequence to enable the sustained expression of O:2 LPS and prevent its conversion to O:9 through tyvelose epimerase activity. The resulting new strain, ZH9PA, incorporated these two genetic changes and exhibited comparable growth kinetics to the parental ZH9 strain. A formulation containing both ZH9 and ZH9PA strains together constitutes a new bivalent vaccine candidate that targets both S. Typhi and S. Paratyphi A antigens to address a major global healthcare gap for enteric fever prophylaxis. This vaccine is now being tested in a Phase I clinical trial (NCT04349553).
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20
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Sears KT, Galen JE, Tennant SM. Advances in the development of Salmonella-based vaccine strategies for protection against Salmonellosis in humans. J Appl Microbiol 2021; 131:2640-2658. [PMID: 33665941 PMCID: PMC9292744 DOI: 10.1111/jam.15055] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/18/2021] [Accepted: 03/02/2021] [Indexed: 11/29/2022]
Abstract
Salmonella spp. are important human pathogens globally causing millions of cases of typhoid fever and non‐typhoidal salmonellosis annually. There are only a few vaccines licensed for use in humans which all target Salmonella enterica serovar Typhi. Vaccine development is hampered by antigenic diversity between the thousands of serovars capable of causing infection in humans. However, a number of attenuated candidate vaccine strains are currently being developed. As facultative intracellular pathogens with multiple systems for transporting effector proteins to host cells, attenuated Salmonella strains can also serve as ideal tools for the delivery of foreign antigens to create multivalent live carrier vaccines for simultaneous immunization against several unrelated pathogens. Further, the ease with which Salmonella can be genetically modified and the extensive knowledge of the virulence mechanisms of this pathogen means that this bacterium has often served as a model organism to test new approaches. In this review we focus on (1) recent advances in live attenuated Salmonella vaccine development, (2) improvements in expression of foreign antigens in carrier vaccines and (3) adaptation of attenuated strains as sources of purified antigens and vesicles that can be used for subunit and conjugate vaccines or together with attenuated vaccine strains in heterologous prime‐boosting immunization strategies. These advances have led to the development of new vaccines against Salmonella which have or will soon be tested in clinical trials.
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Affiliation(s)
- K T Sears
- Center for Vaccine Development and Global Health, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - J E Galen
- Center for Vaccine Development and Global Health, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - S M Tennant
- Center for Vaccine Development and Global Health, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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21
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Foster T, Falletta J, Amin N, Rahman M, Liu P, Raj S, Mills F, Petterson S, Norman G, Moe C, Willetts J. Modelling faecal pathogen flows and health risks in urban Bangladesh: Implications for sanitation decision making. Int J Hyg Environ Health 2021; 233:113669. [PMID: 33578186 DOI: 10.1016/j.ijheh.2020.113669] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 11/19/2020] [Accepted: 11/24/2020] [Indexed: 12/29/2022]
Abstract
Faecal-oral infections are a major component of the disease burden in low-income contexts, with inadequate sanitation seen as a contributing factor. However, demonstrating health effects of sanitation interventions - particularly in urban areas - has proved challenging and there is limited empirical evidence to support sanitation decisions that maximise health gains. This study aimed to develop, apply and validate a systems modelling approach to inform sanitation infrastructure and service decision-making in urban environments by examining enteric pathogen inputs, transport and reduction by various sanitation systems, and estimating corresponding exposure and public health impacts. The health effects of eight sanitation options were assessed in a low-income area in Dhaka, Bangladesh, with a focus on five target pathogens (Shigella, Vibrio cholerae, Salmonella Typhi, norovirus GII and Giardia). Relative to the sanitation base case in the study site (24% septic tanks, 5% holding tanks and 71% toilets discharging directly to open drains), comprehensive coverage of septic tanks was estimated to reduce the disease burden in disability-adjusted life years (DALYs) by 48-72%, while complete coverage of communal scale anaerobic baffled reactors was estimated to reduce DALYs by 67-81%. Despite these improvements, a concerning health risk persists with these systems as a result of effluent discharge to open drains, particularly when the systems are poorly managed. Other sanitation options, including use of constructed wetlands and small bore sewerage, demonstrated further reductions in local health risk, though several still exported pathogens into neighbouring areas, simply transferring risk to downstream communities. The study revealed sensitivity to and a requirement for further evidence on log reduction values for different sanitation systems under varying performance conditions, pathogen flows under flooding conditions as well as pathogen shedding and human exposure in typical low-income urban settings. Notwithstanding variability and uncertainties in input parameters, systems modelling can be a feasible and customisable approach to consider the relative health impact of different sanitation options across various contexts, and stands as a valuable tool to guide urban sanitation decision-making.
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Affiliation(s)
- Tim Foster
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
| | - Jay Falletta
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
| | - Nuhu Amin
- Environmental Interventions Unit, Infectious Disease Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
| | - Mahbubur Rahman
- Environmental Interventions Unit, Infectious Disease Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
| | - Pengbo Liu
- Center for Global Safe Water, Sanitation, and Hygiene, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
| | - Suraja Raj
- Center for Global Safe Water, Sanitation, and Hygiene, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
| | - Freya Mills
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
| | - Susan Petterson
- Water & Health Pty Ltd., 13 Lord St, North Sydney, NSW, 2060, Australia; School of Medicine, Griffith University, Parklands Drive, Southport, QLD, 4222, Australia.
| | - Guy Norman
- Water and Sanitation for the Urban Poor, 10 Queen Street Place, London, EC4R 1BE, UK.
| | - Christine Moe
- Center for Global Safe Water, Sanitation, and Hygiene, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
| | - Juliet Willetts
- Institute for Sustainable Futures, University of Technology Sydney, 235 Jones St, Ultimo, NSW, 2007, Australia.
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22
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Ashwin H, Sadlova J, Vojtkova B, Becvar T, Lypaczewski P, Schwartz E, Greensted E, Van Bocxlaer K, Pasin M, Lipinski KS, Parkash V, Matlashewski G, Layton AM, Lacey CJ, Jaffe CL, Volf P, Kaye PM. Characterization of a new Leishmania major strain for use in a controlled human infection model. Nat Commun 2021; 12:215. [PMID: 33431825 PMCID: PMC7801518 DOI: 10.1038/s41467-020-20569-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/01/2020] [Indexed: 12/17/2022] Open
Abstract
Leishmaniasis is widely regarded as a vaccine-preventable disease, but the costs required to reach pivotal Phase 3 studies and uncertainty about which candidate vaccines should be progressed into human studies significantly limits progress in vaccine development for this neglected tropical disease. Controlled human infection models (CHIMs) provide a pathway for accelerating vaccine development and to more fully understand disease pathogenesis and correlates of protection. Here, we describe the isolation, characterization and GMP manufacture of a new clinical strain of Leishmania major. Two fresh strains of L. major from Israel were initially compared by genome sequencing, in vivo infectivity and drug sensitivity in mice, and development and transmission competence in sand flies, allowing one to be selected for GMP production. This study addresses a major roadblock in the development of vaccines for leishmaniasis, providing a key resource for CHIM studies of sand fly transmitted cutaneous leishmaniasis.
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Affiliation(s)
- Helen Ashwin
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Jovana Sadlova
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, Prague, Czech Republic
| | - Barbora Vojtkova
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, Prague, Czech Republic
| | - Tomas Becvar
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, Prague, Czech Republic
| | - Patrick Lypaczewski
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Eli Schwartz
- The Center for Geographic Medicine and Tropical Diseases, Chaim Sheba Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Elizabeth Greensted
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Katrien Van Bocxlaer
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | | | | | - Vivak Parkash
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Greg Matlashewski
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Alison M Layton
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Charles J Lacey
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Charles L Jaffe
- The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
| | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, Prague, Czech Republic.
| | - Paul M Kaye
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK.
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23
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Gibani MM, Jin C, Shrestha S, Moore M, Norman L, Voysey M, Jones E, Blackwell L, Thomaides-Brears H, Hill J, Blohmke CJ, Dobinson HC, Baker P, Jones C, Campbell D, Mujadidi YF, Plested E, Preciado-Llanes L, Napolitani G, Simmons A, Gordon MA, Angus B, Darton TC, Cerundulo V, Pollard AJ. Homologous and heterologous re-challenge with Salmonella Typhi and Salmonella Paratyphi A in a randomised controlled human infection model. PLoS Negl Trop Dis 2020; 14:e0008783. [PMID: 33079959 PMCID: PMC7598925 DOI: 10.1371/journal.pntd.0008783] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/30/2020] [Accepted: 09/08/2020] [Indexed: 11/19/2022] Open
Abstract
Enteric fever is a systemic infection caused by Salmonella Typhi or Paratyphi A. In many endemic areas, these serovars co-circulate and can cause multiple infection-episodes in childhood. Prior exposure is thought to confer partial, but incomplete, protection against subsequent attacks of enteric fever. Empirical data to support this hypothesis are limited, and there are few studies describing the occurrence of heterologous-protection between these closely related serovars. We performed a challenge-re-challenge study using a controlled human infection model (CHIM) to investigate the extent of infection-derived immunity to Salmonella Typhi or Paratyphi A infection. We recruited healthy volunteers into two groups: naïve volunteers with no prior exposure to Salmonella Typhi/Paratyphi A and volunteers previously-exposed to Salmonella Typhi or Paratyphi A in earlier CHIM studies. Within each group, participants were randomised 1:1 to oral challenge with either Salmonella Typhi (104 CFU) or Paratyphi A (103 CFU). The primary objective was to compare the attack rate between naïve and previously challenged individuals, defined as the proportion of participants per group meeting the diagnostic criteria of temperature of ≥38°C persisting for ≥12 hours and/or S. Typhi/Paratyphi bacteraemia up to day 14 post challenge. The attack-rate in participants who underwent homologous re-challenge with Salmonella Typhi was reduced compared with challenged naïve controls, although this reduction was not statistically significant (12/27[44%] vs. 12/19[63%]; Relative risk 0.70; 95% CI 0.41-1.21; p = 0.24). Homologous re-challenge with Salmonella Paratyphi A also resulted in a lower attack-rate than was seen in challenged naïve controls (3/12[25%] vs. 10/18[56%]; RR0.45; 95% CI 0.16-1.30; p = 0.14). Evidence of protection was supported by a post hoc analysis in which previous exposure was associated with an approximately 36% and 57% reduced risk of typhoid or paratyphoid disease respectively on re-challenge. Individuals who did not develop enteric fever on primary exposure were significantly more likely to be protected on re-challenge, compared with individuals who developed disease on primary exposure. Heterologous re-challenge with Salmonella Typhi or Salmonella Paratyphi A was not associated with a reduced attack rate following challenge. Within the context of the model, prior exposure was not associated with reduced disease severity, altered microbiological profile or boosting of humoral immune responses. We conclude that prior Salmonella Typhi and Paratyphi A exposure may confer partial but incomplete protection against subsequent infection, but with a comparable clinical and microbiological phenotype. There is no demonstrable cross-protection between these serovars, consistent with the co-circulation of Salmonella Typhi and Paratyphi A. Collectively, these data are consistent with surveillance and modelling studies that indicate multiple infections can occur in high transmission settings, supporting the need for vaccines to reduce the burden of disease in childhood and achieve disease control. Trial registration NCT02192008; clinicaltrials.gov.
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Affiliation(s)
- Malick M. Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
- Department of Infectious Diseases, Imperial College London, United Kingdom
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Sonu Shrestha
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Maria Moore
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Lily Norman
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Luke Blackwell
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Helena Thomaides-Brears
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Jennifer Hill
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Christoph J. Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Hazel C. Dobinson
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Philip Baker
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Danielle Campbell
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Yama F. Mujadidi
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Emma Plested
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
| | - Lorena Preciado-Llanes
- Institute for Infection and Global Health, University of Liverpool, United Kingdom
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| | - Giorgio Napolitani
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| | - Alison Simmons
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| | - Melita A. Gordon
- Institute for Infection and Global Health, University of Liverpool, United Kingdom
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Brian Angus
- Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Thomas C. Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Vincenzo Cerundulo
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| | - Andrew J. Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, United Kingdom
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24
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Noé A, Cargill TN, Nielsen CM, Russell AJC, Barnes E. The Application of Single-Cell RNA Sequencing in Vaccinology. J Immunol Res 2020; 2020:8624963. [PMID: 32802896 PMCID: PMC7411487 DOI: 10.1155/2020/8624963] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/09/2020] [Indexed: 02/06/2023] Open
Abstract
Single-cell RNA sequencing allows highly detailed profiling of cellular immune responses from limited-volume samples, advancing prospects of a new era of systems immunology. The power of single-cell RNA sequencing offers various opportunities to decipher the immune response to infectious diseases and vaccines. Here, we describe the potential uses of single-cell RNA sequencing methods in prophylactic vaccine development, concentrating on infectious diseases including COVID-19. Using examples from several diseases, we review how single-cell RNA sequencing has been used to evaluate the immunological response to different vaccine platforms and regimens. By highlighting published and unpublished single-cell RNA sequencing studies relevant to vaccinology, we discuss some general considerations how the field could be enriched with the widespread adoption of this technology.
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MESH Headings
- Animals
- Betacoronavirus/immunology
- COVID-19
- Cell Line
- Clinical Trials as Topic
- Coronavirus Infections/epidemiology
- Coronavirus Infections/immunology
- Coronavirus Infections/prevention & control
- Coronavirus Infections/virology
- Disease Models, Animal
- Drug Evaluation, Preclinical
- Host-Pathogen Interactions/genetics
- Host-Pathogen Interactions/immunology
- Humans
- Immunity, Cellular/genetics
- Immunity, Innate/genetics
- Immunogenicity, Vaccine
- Pandemics/prevention & control
- Pneumonia, Viral/epidemiology
- Pneumonia, Viral/immunology
- Pneumonia, Viral/prevention & control
- Pneumonia, Viral/virology
- RNA, Viral/isolation & purification
- RNA-Seq/methods
- SARS-CoV-2
- Single-Cell Analysis
- Vaccinology/methods
- Viral Vaccines/administration & dosage
- Viral Vaccines/immunology
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Affiliation(s)
- Andrés Noé
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Tamsin N. Cargill
- Peter Medawar Building for Pathogen Research and Oxford NIHR Biomedical Research Centre, Nuffield Department of Medicine, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
- Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Carolyn M. Nielsen
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | | | - Eleanor Barnes
- Peter Medawar Building for Pathogen Research and Oxford NIHR Biomedical Research Centre, Nuffield Department of Medicine, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
- Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford OX3 9DU, UK
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25
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Syed KA, Saluja T, Cho H, Hsiao A, Shaikh H, Wartel TA, Mogasale V, Lynch J, Kim JH, Excler JL, Sahastrabuddhe S. Review on the Recent Advances on Typhoid Vaccine Development and Challenges Ahead. Clin Infect Dis 2020; 71:S141-S150. [PMID: 32725225 PMCID: PMC7388714 DOI: 10.1093/cid/ciaa504] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Control of Salmonella enterica serovar typhi (S. typhi), the agent of typhoid fever, continues to be a challenge in many low- and middle-income countries. The major transmission route of S. typhi is fecal-oral, through contaminated food and water; thus, the ultimate measures for typhoid fever prevention and control include the provision of safe water, improved sanitation, and hygiene. Considering the increasing evidence of the global burden of typhoid, particularly among young children, and the long-term horizon for sustained, effective water and sanitation improvements in low-income settings, a growing consensus is to emphasize preventive vaccination. This review provides an overview of the licensed typhoid vaccines and vaccine candidates under development, and the challenges ahead for introduction.
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Affiliation(s)
- Khalid Ali Syed
- MSD-Wellcome Trust Hilleman Laboratories Pvt Ltd, New Delhi, India
| | - Tarun Saluja
- International Vaccine Institute, Seoul, Republic of Korea
| | - Heeyoun Cho
- International Vaccine Institute, Seoul, Republic of Korea
| | - Amber Hsiao
- Technische Universität Berlin, Berlin, Germany
| | | | - T Anh Wartel
- International Vaccine Institute, Seoul, Republic of Korea
| | | | - Julia Lynch
- International Vaccine Institute, Seoul, Republic of Korea
| | - Jerome H Kim
- International Vaccine Institute, Seoul, Republic of Korea
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26
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Gibani MM, Voysey M, Jin C, Jones C, Thomaides-Brears H, Jones E, Baker P, Morgan M, Simmons A, Gordon MA, Cerundolo V, Pitzer VE, Angus B, Levine MM, Darton TC, Pollard AJ. The Impact of Vaccination and Prior Exposure on Stool Shedding of Salmonella Typhi and Salmonella Paratyphi in 6 Controlled Human Infection Studies. Clin Infect Dis 2020; 68:1265-1273. [PMID: 30252031 PMCID: PMC6452003 DOI: 10.1093/cid/ciy670] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 08/07/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Shedding of Salmonella Typhi or Paratyphi in the stool or urine leads to contamination of food or water, which is a prerequisite for transmission of enteric fever. Currently, there are limited data on the effect of vaccination or prior exposure on stool shedding. METHODS Six Salmonella Typhi or Paratyphi human challenge studies were conducted between 2011 and 2017. Participants were either unvaccinated or vaccinated with 1 of 4 vaccines: Vi-polysaccharide (Vi-PS), Vi-tetanus-toxoid conjugate vaccine (Vi-TT), live oral Ty21a vaccine, or an experimental vaccine (M01ZH09). Daily stool cultures were collected for 14 days after challenge. RESULTS There were 4934 stool samples collected from 430 volunteers. Participants who received Vi-PS or Vi-TT shed less than unvaccinated participants (odds ratio [OR], 0.34; 95% confidence interval [CI], 0.15-0.77; P = .010 and OR, 0.41; 95% CI, 0.19-0.91, P = .029 for Vi-PS and Vi-TT, respectively). Higher anti-Vi immunoglobulin G titers were associated with less shedding of S. Typhi (P < .0001). A nonsignificant reduction in shedding was associated with Ty21a vaccine (OR, 0.57; 95% CI, 0.27-1.20; P = .140). Individuals previously exposed to S. Typhi shed less than previously unexposed individuals (OR, 0.30; 95% CI, 0.1-0.8; P = .016). Shedding of S. Typhi was more common than S. Paratyphi. CONCLUSIONS Prior vaccination with Vi vaccines, or natural infection, reduces onward transmission of S. Typhi. Field trials of Vi-TT should be designed to detect indirect protection, reflecting the consequence of reduced stool shedding observed in the human challenge model.
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Affiliation(s)
- Malick M Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,Nuffield Department of Primary Care Health Sciences, University of Oxford, United Kingdom
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | | | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Philip Baker
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford
| | - Marcus Morgan
- Oxford University Hospitals, National Health Service Foundation Trust, United Kingdom
| | - Alison Simmons
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom.,Translational Gastroenterology Unit, University of Oxford, United Kingdom
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre.,Institute for Infection and Global Health, University of Liverpool, United Kingdom
| | - Vincenzo Cerundolo
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
| | - Brian Angus
- Oxford University Hospitals, National Health Service Foundation Trust, United Kingdom.,Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore
| | - Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford.,National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
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27
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Islam MT, Im J, Ahmmed F, Kim DR, Khan AI, Zaman K, Ali M, Marks F, Qadri F, Kim JH, Clemens JD. Use of Typhoid Vi-Polysaccharide Vaccine as a Vaccine Probe to Delineate Clinical Criteria for Typhoid Fever. Am J Trop Med Hyg 2020; 103:665-671. [PMID: 32588803 PMCID: PMC7410438 DOI: 10.4269/ajtmh.19-0968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Blood cultures (BCs) detect an estimated 50% of typhoid fever cases. There is need for validated clinical criteria to define cases that are BC negative, both to help direct empiric antibiotic treatment and to better evaluate the magnitude of protection conferred by typhoid vaccines. To derive and validate a clinical rule for defining BC-negative typhoid fever, we assessed, in a cluster-randomized effectiveness trial of Vi-polysaccharide (ViPS) typhoid vaccine in Kolkata, India, 14,797 episodes of fever lasting at least 3 days during 4 years of comprehensive, BC-based surveillance of 70,865 persons. A recursive partitioning algorithm was used to develop a decision rule to predict BC-proven typhoid cases with a diagnostic specificity of 97–98%. To validate this rule as a definition for BC-negative typhoid fever, we assessed whether the rule defined culture-negative syndromes prevented by ViPS vaccine. In a training subset of individuals, we identified the following two rules: rule 1: patients aged < 15 years with prolonged fever accompanied by a measured body temperature ≥ 100°F, headache, and nausea; rule 2: patients aged ≥ 15 years with prolonged fever accompanied by nausea and palpable liver but without constipation. The adjusted protective efficacy of ViPS against clinical typhoid defined by these rules in persons aged ≥ 2 years in a separate validation subset was 33% (95% CI: 4–53%). We have defined and validated a clinical rule for predicting BC-negative typhoid fever using a novel vaccine probe approach. If validated in other settings, this rule may be useful to guide clinical care and to enhance typhoid vaccine evaluations.
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Affiliation(s)
- Md Taufiqul Islam
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Justin Im
- International Vaccine Institute, Seoul, Republic of Korea
| | - Faisal Ahmmed
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Deok Ryun Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Ashraful Islam Khan
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Khalequ Zaman
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Florian Marks
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,International Vaccine Institute, Seoul, Republic of Korea
| | - Firdausi Qadri
- International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Jerome H Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - John D Clemens
- Korea University College of Medicine, Seoul, South Korea.,UCLA Fielding School of Public Health, Los Angeles, California.,International Centre for Diarrheal Disease Research, Bangladesh, Dhaka, Bangladesh
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Liu X, Pitzer VE, Pollard AJ, Voysey M. The Design and Analysis of Seroefficacy Studies for Typhoid Conjugate Vaccines. Clin Infect Dis 2020; 68:S183-S190. [PMID: 30845326 PMCID: PMC6405265 DOI: 10.1093/cid/ciy1119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Background Demonstrating the efficacy of new Vi-conjugate typhoid vaccines is challenging, due to the cost of field trials requiring tens of thousands of participants. New trial designs that use serologically defined typhoid infections (seroefficacy trials) rather than blood culture positivity as a study endpoint may be useful to assess efficacy using small trials. Methods We developed a model for Vi–immunoglobin G antibody responses to a Vi-vaccine, incorporating decay over time and natural boosting due to endemic exposures. From this, we simulated clinical trials in which 2 blood samples were taken during follow-up and the relative risk of a serologically defined typhoid infection (seroefficacy) was computed. We aimed to determine (1) whether seroefficacy trial designs could substantially reduce sample sizes, compared with trials using blood culture–confirmed cases; (3) whether the rate of case detection was higher in seroefficacy trials; and (3) the optimal timing of sample collection. Results The majority (>90%) of blood culture–positive typhoid cases remain unobserved in surveillance studies. In contrast, under-detection in simulated seroefficacy trials of equivalent vaccines was as little as 26%, and estimates of the relative risk of typhoid infection were unbiased. For simulated trials of non-equivalent vaccines, relative risks were slightly inflated by at least 5%, depending on the sample collection times. Seroefficacy trials required as few as 460 participants per arm, compared with 10 000 per arm for trials using blood culture–confirmed cases. Conclusions Seroefficacy trials can establish the efficacy of new conjugate vaccines using small trials that enroll hundreds rather than thousands of participants, and without the need for resource-intensive typhoid fever surveillance programs.
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Affiliation(s)
- Xinxue Liu
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
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O'Reilly PJ, Pant D, Shakya M, Basnyat B, Pollard AJ. Progress in the overall understanding of typhoid fever: implications for vaccine development. Expert Rev Vaccines 2020; 19:367-382. [PMID: 32238006 DOI: 10.1080/14760584.2020.1750375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Typhoid fever continues to have a substantial impact on human health, especially in Asia and sub-Saharan Africa. Access to safe water, and adequate sanitation and hygiene remain the cornerstone of prevention, but these are not widely available in many impoverished settings. The emergence of antibiotic resistance affects typhoid treatment and adds urgency to typhoid control efforts. Vaccines provide opportunities to prevent and control typhoid fever in endemic settings. AREAS COVERED Literature search was performed looking for evidence concerning the global burden of typhoid and strategies for the prevention and treatment of typhoid fever. Cost of illness, available typhoid and paratyphoid vaccines and cost-effectiveness were also reviewed. The objective was to provide a critical overview of typhoid fever, in order to assess the current understanding and potential future directions for typhoid treatment and control. EXPERT COMMENTARY Our understanding of typhoid burden and methods of prevention has grown over recent years. However, typhoid fever still has a significant impact on health in low and middle-income countries. Introduction of typhoid conjugate vaccines to the immunization schedule is expected to make a major contribution to control of typhoid fever in endemic countries, although vaccination alone is unlikely to eliminate the disease.
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Affiliation(s)
- Peter J O'Reilly
- Oxford Vaccine Group, Department of Pediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre , Oxford, UK
| | - Dikshya Pant
- Department of Paediatrics, Patan Academy of Health Sciences, Patan Hospital , Kathmandu, Nepal
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences , Kathmandu, Nepal
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences , Kathmandu, Nepal
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Pediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre , Oxford, UK
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30
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Langenberg MCC, Dekkers OM, Roestenberg M. Are placebo controls necessary in controlled human infection trials for vaccines? THE LANCET. INFECTIOUS DISEASES 2020; 20:e69-e74. [PMID: 32142640 DOI: 10.1016/s1473-3099(20)30020-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 01/02/2020] [Accepted: 01/12/2020] [Indexed: 12/18/2022]
Abstract
Controlled human infection trials, whereby a small group of healthy participants is deliberately exposed to a pathogen under controlled circumstances, can provide preliminary data for vaccine efficacy and for the selection of the most promising candidate vaccines for field trials. Because of the potential harm to participants through the deliberate exposure to a pathogen, the use of smaller groups minimises the cumulative risk. As such, a control group that receives a placebo vaccine followed by controlled exposure to a pathogen should be scientifically well justified. As these types of trials are designed to generate consistent infection rates and thus comparable outcomes across populations and trial sites, data from past studies (historical data) could be used as a valid alternative to placebo groups. In this Personal View, we review this option and highlight the considerations for choosing historical data as a suitable control. For the widespread application of this method, responsibility for the centralisation and sharing of data from controlled human infection trials lies with the scientific community.
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Affiliation(s)
| | - Olaf M Dekkers
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, Netherlands
| | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands.
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31
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Jin C, Gibani MM, Pennington SH, Liu X, Ardrey A, Aljayyoussi G, Moore M, Angus B, Parry CM, Biagini GA, Feasey NA, Pollard AJ. Treatment responses to Azithromycin and Ciprofloxacin in uncomplicated Salmonella Typhi infection: A comparison of Clinical and Microbiological Data from a Controlled Human Infection Model. PLoS Negl Trop Dis 2019; 13:e0007955. [PMID: 31877141 PMCID: PMC6948818 DOI: 10.1371/journal.pntd.0007955] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 01/08/2020] [Accepted: 11/26/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The treatment of enteric fever is complicated by the emergence of antimicrobial resistant Salmonella Typhi. Azithromycin is commonly used for first-line treatment of uncomplicated enteric fever, but the response to treatment may be sub-optimal in some patient groups when compared with fluoroquinolones. METHODS We performed an analysis of responses to treatment with azithromycin (500mg once-daily, 14 days) or ciprofloxacin (500mg twice-daily, 14 days) in healthy UK volunteers (18-60 years) enrolled into two Salmonella controlled human infection studies. Study A was a single-centre, open-label, randomised trial. Participants were randomised 1:1 to receive open-label oral ciprofloxacin or azithromycin, stratified by vaccine group (Vi-polysaccharide, Vi-conjugate or control Men-ACWY vaccine). Study B was an observational challenge/re-challenge study, where participants were randomised to challenge with Salmonella Typhi or Salmonella Paratyphi A. Outcome measures included fever clearance time, blood-culture clearance time and a composite measure of prolonged treatment response (persistent fever ≥38.0°C for ≥72 hours, persistently positive S. Typhi blood cultures for ≥72 hours, or change in antibiotic treatment). Both trials are registered with ClinicalTrials.gov (NCT02324751 and NCT02192008). FINDINGS In 81 participants diagnosed with S. Typhi in two studies, treatment with azithromycin was associated with prolonged bacteraemia (median 90.8 hours [95% CI: 65.9-93.8] vs. 20.1 hours [95% CI: 7.8-24.3], p<0.001) and prolonged fever clearance times <37.5°C (hazard ratio 2.4 [95%CI: 1.2-5.0]; p = 0.02). Results were consistent when studies were analysed independently and in a sub-group of participants with no history of vaccination or previous challenge. A prolonged treatment response was observed significantly more frequently in the azithromycin group (28/52 [54.9%]) compared with the ciprofloxacin group (1/29 [3.5%]; p<0.001). In participants treated with azithromycin, observed systemic plasma concentrations of azithromycin did not exceed the minimum inhibitory concentration (MIC), whilst predicted intracellular concentrations did exceed the MIC. In participants treated with ciprofloxacin, the observed systemic plasma concentrations and predicted intracellular concentrations of ciprofloxacin exceeded the MIC. INTERPRETATION Azithromycin at a dose of 500mg daily is an effective treatment for fully sensitive strains of S. Typhi but is associated with delayed treatment response and prolonged bacteraemia when compared with ciprofloxacin within the context of a human challenge model. Whilst the cellular accumulation of azithromycin is predicted to be sufficient to treat intracellular S. Typhi, systemic exposure may be sub-optimal for the elimination of extracellular circulating S. Typhi. In an era of increasing antimicrobial resistance, further studies are required to define appropriate azithromycin dosing regimens for enteric fever and to assess novel treatment strategies, including combination therapies. TRIAL REGISTRATION ClinicalTrials.gov (NCT02324751 and NCT02192008).
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Affiliation(s)
- Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Malick M. Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
- Department of Infectious Diseases, Imperial College London, London, United Kingdom
| | - Shaun H. Pennington
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Xinxue Liu
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Alison Ardrey
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ghaith Aljayyoussi
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Maria Moore
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Brian Angus
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Christopher M. Parry
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- School of Tropical Medicine and Global Health, Nagsaki University, Nagasaki, Japan
| | - Giancarlo A. Biagini
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Nicholas A. Feasey
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- Malawi Liverpool Wellcome Trust Clinical research Programme, Blantyre, Malawi
| | - Andrew J. Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
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32
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Meiring JE, Giubilini A, Savulescu J, Pitzer VE, Pollard AJ. Generating the Evidence for Typhoid Vaccine Introduction: Considerations for Global Disease Burden Estimates and Vaccine Testing Through Human Challenge. Clin Infect Dis 2019; 69:S402-S407. [PMID: 31612941 PMCID: PMC6792111 DOI: 10.1093/cid/ciz630] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Typhoid fever has had a major impact on human populations, with the causative pathogen Salmonella enterica serovar Typhi implicated in many outbreaks through history. The current burden of disease is estimated at 11-18 million infections annually, with the majority of infections located in Africa and South Asia. Data that have been used to estimate burden are limited to a small number of blood-culture surveillance studies, largely from densely populated urban centers. Extrapolating these data to estimate disease burden within and across countries highlights the lack of precision in global figures. A number of approaches have been developed, characterizing different geographical areas by water-based risk factors for typhoid infection or broader measures of health and development to more accurately extrapolate incidence. Recognition of the substantial disease burden is essential for policy-makers considering vaccine introduction. Typhoid vaccines have been in development for >100 years. The Vi polysaccharide (ViPS) and Ty21a vaccines have had a World Health Organization (WHO) recommendation for programmatic use in countries with high burden for 10 years, with 1 ViPS vaccine also having WHO prequalification. Despite this, uptake and introduction of these vaccines has been minimal. The development of a controlled human infection model (CHIM) enabled the accelerated testing of the newly WHO-prequalified ViPS-tetanus toxoid protein conjugate vaccine, providing efficacy estimates for the vaccine, prior to larger field trials. There is an urgency to the global control of enteric fever due to the escalating problem of antimicrobial resistance. With more accurate burden of disease estimates and a vaccine showing efficacy in CHIM, that control is now a possibility.
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Affiliation(s)
- James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, United Kingdom
| | - Alberto Giubilini
- Oxford Uehiro Centre for Practical Ethics, University of Oxford, United Kingdom
| | - Julian Savulescu
- Oxford Uehiro Centre for Practical Ethics, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, United Kingdom
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33
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Oguti B, Gibani M, Darlow C, Waddington CS, Jin C, Plested E, Campbell D, Jones C, Darton TC, Pollard AJ. Factors influencing participation in controlled human infection models: a pooled analysis from six enteric fever studies. Wellcome Open Res 2019. [DOI: 10.12688/wellcomeopenres.15469.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background: Enteric fever is an acute febrile-illness caused by infection with the human-restricted Salmonella serovars Typhi and Paratyphi. Controlled human infection models (CHIM) of S. Typhi and Paratyphi infection are used to accelerate vaccine development and to better understand host-pathogen interactions. The primary motivations for participants to take part in these studies are unknown. We studied participant motivations, attitudes and the factors influencing CHIM study participation. Methods: Participant surveys were nested in six enteric fever CHIM studies conducted at a single centre in Oxford, UK, between 2011 and 2017. All eligible participants received one invitation to complete an anonymous, self-administered paper or online survey on either day 28 or 60 after challenge. A descriptive analysis was performed on these pooled data. All studies were included, to minimize selection bias. Results: Survey response rates varied from 33.0%-86.1%, yielding 201 participants. In the cohort, 113/198(57.0%) were educated to bachelor’s level, 61.6% were employed, 30.3% were students and 4.6% were unemployed. The most commonly cited motivations for CHIM study participation were a desire to contribute to the progression of medicine (170/201; 84.6%); the prospect of financial reimbursement (166/201; 82.6%) and curiosity about clinical trials (117/201; 57.2%). The majority of respondents (139/197; 70.6%) reported that most people advised them against participation. Conclusion: Motivation to participate in a CHIM study was multi-factorial and heavily influenced by internal drivers beyond monetary reimbursement alone. High educational attainment and employment may be protective factors against financial inducement; however, further research is needed, particularly with CHIM studies expanding to low-income and middle-income countries.
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34
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Blohmke CJ, Muller J, Gibani MM, Dobinson H, Shrestha S, Perinparajah S, Jin C, Hughes H, Blackwell L, Dongol S, Karkey A, Schreiber F, Pickard D, Basnyat B, Dougan G, Baker S, Pollard AJ, Darton TC. Diagnostic host gene signature for distinguishing enteric fever from other febrile diseases. EMBO Mol Med 2019; 11:e10431. [PMID: 31468702 PMCID: PMC6783646 DOI: 10.15252/emmm.201910431] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 07/30/2019] [Accepted: 08/09/2019] [Indexed: 12/19/2022] Open
Abstract
Misdiagnosis of enteric fever is a major global health problem, resulting in patient mismanagement, antimicrobial misuse and inaccurate disease burden estimates. Applying a machine learning algorithm to host gene expression profiles, we identified a diagnostic signature, which could distinguish culture-confirmed enteric fever cases from other febrile illnesses (area under receiver operating characteristic curve > 95%). Applying this signature to a culture-negative suspected enteric fever cohort in Nepal identified a further 12.6% as likely true cases. Our analysis highlights the power of data-driven approaches to identify host response patterns for the diagnosis of febrile illnesses. Expression signatures were validated using qPCR, highlighting their utility as PCR-based diagnostics for use in endemic settings.
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Affiliation(s)
- Christoph J Blohmke
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | | | - Malick M Gibani
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Hazel Dobinson
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Sonu Shrestha
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Soumya Perinparajah
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Celina Jin
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Harri Hughes
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Luke Blackwell
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Sabina Dongol
- Patan Academy of Healthy SciencesOxford University Clinical Research UnitKathmanduNepal
| | - Abhilasha Karkey
- Patan Academy of Healthy SciencesOxford University Clinical Research UnitKathmanduNepal
| | | | - Derek Pickard
- Infection Genomics ProgramThe Wellcome Trust Sanger InstituteHinxtonUK
| | - Buddha Basnyat
- Patan Academy of Healthy SciencesOxford University Clinical Research UnitKathmanduNepal
| | - Gordon Dougan
- Infection Genomics ProgramThe Wellcome Trust Sanger InstituteHinxtonUK
| | - Stephen Baker
- The Hospital for Tropical DiseasesWellcome Trust Major Overseas ProgrammeOxford University Clinical Research UnitHo Chi Minh CityVietnam
| | - Andrew J Pollard
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
| | - Thomas C Darton
- Department of PaediatricsCentre for Clinical Vaccinology and Tropical MedicineOxford Vaccine GroupOxfordUK
- Oxford National Institute of Health Research Biomedical CentreUniversity of OxfordOxfordUK
- The Hospital for Tropical DiseasesWellcome Trust Major Overseas ProgrammeOxford University Clinical Research UnitHo Chi Minh CityVietnam
- Department of Infection, Immunity and Cardiovascular DiseaseUniversity of SheffieldSheffieldUK
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Kingsley RA, Langridge G, Smith SE, Makendi C, Fookes M, Wileman TM, El Ghany MA, Keith Turner A, Dyson ZA, Sridhar S, Pickard D, Kay S, Feasey N, Wong V, Barquist L, Dougan G. Functional analysis of Salmonella Typhi adaptation to survival in water. Environ Microbiol 2019; 20:4079-4090. [PMID: 30450829 PMCID: PMC6282856 DOI: 10.1111/1462-2920.14458] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/16/2018] [Accepted: 10/21/2018] [Indexed: 11/28/2022]
Abstract
Contaminated water is a major risk factor associated with the transmission of Salmonella enterica serovar Typhi (S. Typhi), the aetiological agent of human typhoid. However, little is known about how this pathogen adapts to living in the aqueous environment. We used transcriptome analysis (RNA‐seq) and transposon mutagenesis (TraDIS) to characterize these adaptive changes and identify multiple genes that contribute to survival. Over half of the genes in the S. Typhi genome altered expression level within the first 24 h following transfer from broth culture to water, although relatively few did so in the first 30 min. Genes linked to central metabolism, stress associated with arrested proton motive force and respiratory chain factors changed expression levels. Additionally, motility and chemotaxis genes increased expression, consistent with a scavenging lifestyle. The viaB‐associated gene tviC encoding a glcNAc epimerase that is required for Vi polysaccharide biosynthesis was, along with several other genes, shown to contribute to survival in water. Thus, we define regulatory adaptation operating in S. Typhi that facilitates survival in water.
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Affiliation(s)
| | - Gemma Langridge
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Sarah E Smith
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Carine Makendi
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Maria Fookes
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Tom M Wileman
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Moataz Abd El Ghany
- The Westmead Institute for Medical Research, The University of Sydney, Sydney, Australia and Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, Australia
| | - A Keith Turner
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Zoe A Dyson
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Sushmita Sridhar
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Derek Pickard
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Sally Kay
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | | | - Vanessa Wong
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Würzburg, Germany.,Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
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McShane H. Insights and challenges in tuberculosis vaccine development. THE LANCET. RESPIRATORY MEDICINE 2019; 7:810-819. [PMID: 31416767 DOI: 10.1016/s2213-2600(19)30274-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 06/30/2019] [Accepted: 07/15/2019] [Indexed: 02/09/2023]
Abstract
Tuberculosis kills more people than any other pathogen and the need for a universally effective vaccine has never been greater. An effective vaccine will be a key tool in achieving the targets set by WHO in the End TB Strategy. Tuberculosis vaccine development is difficult and slow. Substantial progress has been made in research and development of tuberculosis vaccines in the past 20 years, and two clinical trial results from 2018 provide reason for optimism. However, many challenges to the successful licensure and deployment of an effective tuberculosis vaccine remain. The development of new tools for vaccine evaluation might facilitate these processes, and continued collaborative working and sustained funding will be essential.
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Affiliation(s)
- Helen McShane
- The Jenner Institute, University of Oxford, Oxford, UK.
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37
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Gibani MM, Jones E, Barton A, Jin C, Meek J, Camara S, Galal U, Heinz E, Rosenberg-Hasson Y, Obermoser G, Jones C, Campbell D, Black C, Thomaides-Brears H, Darlow C, Dold C, Silva-Reyes L, Blackwell L, Lara-Tejero M, Jiao X, Stack G, Blohmke CJ, Hill J, Angus B, Dougan G, Galán J, Pollard AJ. Investigation of the role of typhoid toxin in acute typhoid fever in a human challenge model. Nat Med 2019; 25:1082-1088. [PMID: 31270506 PMCID: PMC6892374 DOI: 10.1038/s41591-019-0505-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 05/30/2019] [Indexed: 11/09/2022]
Abstract
Salmonella Typhi is a human host-restricted pathogen that is responsible for typhoid fever in approximately 10.9 million people annually1. The typhoid toxin is postulated to have a central role in disease pathogenesis, the establishment of chronic infection and human host restriction2–6. However, its precise role in typhoid disease in humans is not fully defined. We studied the role of typhoid toxin in acute infection using a randomized, double-blind S. Typhi human challenge model7. Forty healthy volunteers were randomized (1:1) to oral challenge with 104 colony-forming units of wild-type or an isogenic typhoid toxin deletion mutant (TN) of S. Typhi. We observed no significant difference in the rate of typhoid infection (fever ≥38 °C for ≥12 h and/or S. Typhi bacteremia) between participants challenged with wild-type or TN S. Typhi (15 out of 21 (71%) versus 15 out of 19 (79%); P = 0.58). The duration of bacteremia was significantly longer in participants challenged with the TN strain compared with wild-type (47.6 hours (28.9–97.0) versus 30.3(3.6–49.4); P ≤ 0.001). The clinical syndrome was otherwise indistinguishable between wild-type and TN groups. These data suggest that the typhoid toxin is not required for infection and the development of early typhoid fever symptoms within the context of a human challenge model. Further clinical data are required to assess the role of typhoid toxin in severe disease or the establishment of bacterial carriage. Typhoid toxin is not essential for the pathogenesis of typhoid fever in healthy humans challenged with Salmonella Typhi.
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Affiliation(s)
- Malick M Gibani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK. .,Department of Medicine, Imperial College London, London, UK.
| | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Amber Barton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Celina Jin
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Juliette Meek
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Susana Camara
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Ushma Galal
- Nuffield Department of Primary Care Health Sciences, Clinical Trials Unit, University of Oxford, Oxford, UK
| | - Eva Heinz
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Yael Rosenberg-Hasson
- Human Immune Monitoring Center, Institute for Immunity, Transplantation and Infection, Stanford University, Stanford, CA, USA
| | - Gerlinde Obermoser
- Human Immune Monitoring Center, Institute for Immunity, Transplantation and Infection, Stanford University, Stanford, CA, USA
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Danielle Campbell
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Charlotte Black
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Helena Thomaides-Brears
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Christopher Darlow
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Christina Dold
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Laura Silva-Reyes
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Luke Blackwell
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Maria Lara-Tejero
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Xuyao Jiao
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Gabrielle Stack
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Christoph J Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Jennifer Hill
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Brian Angus
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Gordon Dougan
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Medicine, University of Cambridge, Hinxton, UK
| | - Jorge Galán
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
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Mani S, Toapanta FR, McArthur MA, Qadri F, Svennerholm AM, Devriendt B, Phalipon A, Cohen D, Sztein MB. Role of antigen specific T and B cells in systemic and mucosal immune responses in ETEC and Shigella infections, and their potential to serve as correlates of protection in vaccine development. Vaccine 2019; 37:4787-4793. [PMID: 31230883 PMCID: PMC7413037 DOI: 10.1016/j.vaccine.2019.03.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/07/2019] [Accepted: 03/19/2019] [Indexed: 12/13/2022]
Abstract
The generation of robust systemic and mucosal antibody and cell-mediated immune (CMI) responses that are protective, long-lasting, and can quickly be recalled upon subsequent re-exposure to the cognate antigen is the key to the development of effective vaccine candidates. These responses, whether they represent mechanistic or non-mechanistic immunological correlates of protection, usually entail the activation of T cell memory and effector subsets (T-CMI) and induction of long-lasting memory B cells. However, for ETEC and Shigella, the precise role of these key immune cells in primary and secondary (anamnestic) immune responses remains ill-defined. A workshop to address immune correlates for ETEC and Shigella, in general, and to elucidate the mechanistic role of T-cell subsets and B-cells, both systemically and in the mucosal microenvironment, in the development of durable protective immunity against ETEC and Shigella was held at the recent 2nd Vaccines against Shigella and ETEC (VASE) conference in June 2018. This report is a summary of the presentations and the discussion that ensued at the workshop.
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Affiliation(s)
| | - Franklin R Toapanta
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Monica A McArthur
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Firdausi Qadri
- Infectious Diseases Division, International Center for Diarrheal Diseases Research, Dhaka, Bangladesh
| | - Ann-Mari Svennerholm
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Sweden
| | - Bert Devriendt
- Faculty of Veterinary Medicine, Department of Virology, Parasitology, and Immunology, Ghent University, Belgium
| | - Armelle Phalipon
- Molecular Microbial Pathogenesis, INSERM U1202, Institut Pasteur, Paris, France
| | - Daniel Cohen
- School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Marcelo B Sztein
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States.
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Das S, Mohakud NK, Suar M, Sahu BR. Vaccine development for enteric bacterial pathogens: Where do we stand? Pathog Dis 2019; 76:5040763. [PMID: 30052916 DOI: 10.1093/femspd/fty057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/19/2018] [Indexed: 01/06/2023] Open
Abstract
Gut infections triggered by pathogenic bacteria lead to most frequently occurring diarrhea in humans accounting for million deaths annually. Currently, only a few licensed vaccines are available against these pathogens for mostly travelers moving to diarrheal endemic areas. Besides commercialized vaccines, there are many formulations that are either under clinical or pre-clinical stages of development and despite several efforts to improve safety, immunogenicity and efficacy, none of them can confer long-term protective immunity, for which repeated booster doses are always recommended. Further in many countries, financial, social and political constraints have jeopardized vaccine development program against these pathogens that enforce us to gather knowledge on safety, tolerability, immunogenicity and protective efficacy regarding the same. In this review, we analyze safety and efficacy issues of vaccines against five major gut bacteria causing enteric infections. The article also simultaneously describes several barriers for vaccine development and further discusses possible strategies to enhance immunogenicity and efficacy.
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Affiliation(s)
- Susmita Das
- Infection Biology Lab, KIIT School of Biotechnology, Campus XI, Bhubaneswar 751024, India
| | - Nirmal K Mohakud
- Department of Pediatrics, Kalinga Institute of Medical Sciences, Patia, Bhubaneswar 751024, India
| | - Mrutyunjay Suar
- Infection Biology Lab, KIIT School of Biotechnology, Campus XI, Bhubaneswar 751024, India
| | - Bikash R Sahu
- Infection Biology Lab, KIIT School of Biotechnology, Campus XI, Bhubaneswar 751024, India
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Capeding MR, Teshome S, Saluja T, Syed KA, Kim DR, Park JY, Yang JS, Kim YH, Park J, Jo SK, Chon Y, Kothari S, Yang SY, Ham DS, Ryu JH, Hwang HS, Mun JH, Lynch JA, Kim JH, Kim H, Excler JL, Sahastrabuddhe S. Safety and immunogenicity of a Vi-DT typhoid conjugate vaccine: Phase I trial in Healthy Filipino adults and children. Vaccine 2018; 36:3794-3801. [PMID: 29776750 PMCID: PMC6005168 DOI: 10.1016/j.vaccine.2018.05.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/03/2018] [Accepted: 05/07/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND Typhoid fever remains a major public health problem in low- and middle-income countries where children aged 2-14 years bear the greatest burden. Vi polysaccharide is poorly immunogenic in children <2 years of age, and protection in adults is modest. The limitations of Vi polysaccharide vaccines can be overcome by conjugation of the Vi to a carrier protein. A typhoid conjugate vaccine composed of Vi polysaccharide conjugated to diphtheria toxoid (Vi-DT) has been developed. The Phase I study results are presented here. METHODS This was a randomized, observer-blinded Phase I study to assess the safety and immunogenicity of Vi-DT compared to Vi polysaccharide vaccine, conducted in Manila, Philippines. Participants enrolled in an age de-escalation manner (18-45, 6-17 and 2-5 years) were randomized between Test (Vi-DT, 25 µg) administered at 0 and 4 weeks and Comparator (Vi polysaccharide, Typhim Vi® and Vaxigrip®, Sanofi Pasteur) vaccines. RESULTS A total of 144 participants were enrolled (48 by age strata, 24 in Test and Comparator groups each). No serious adverse event was reported in either group. Solicited and unsolicited adverse events were mild or moderate in both groups with the exception of a 4-year old girl in Test group with grade 3 fever which resolved without sequelae. All participants in Test group seroconverted after first and second doses of Vi-DT while the proportions in the Comparator group were 97.1% and 97.2%, after first dose of Typhim Vi® and second dose of Vaxigrip®, respectively. Vi-DT showed 4-fold higher Geometric Mean Titers (GMT) compared to Typhim Vi® (adjusted for age strata, p < 0.001). No further increase of GMT was detected after the second dose of Vi-DT. Anti-DT IgG seroresponse rates were 81.2% and 84.5% post first and second Vi-DT doses, respectively. CONCLUSIONS Vi-DT vaccine was safe, well-tolerated and immunogenic in participants aged 2-45 years. ClinicalTrials.gov registration number: NCT02645032.
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Affiliation(s)
| | - Samuel Teshome
- International Vaccine Institute, Seoul, Republic of Korea
| | - Tarun Saluja
- International Vaccine Institute, Seoul, Republic of Korea.
| | | | - Deok Ryun Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Ju Yeon Park
- International Vaccine Institute, Seoul, Republic of Korea
| | - Jae Seung Yang
- International Vaccine Institute, Seoul, Republic of Korea
| | - Yang Hee Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Jiwook Park
- International Vaccine Institute, Seoul, Republic of Korea
| | - Sue-Kyoung Jo
- International Vaccine Institute, Seoul, Republic of Korea
| | - Yun Chon
- International Vaccine Institute, Seoul, Republic of Korea
| | - Sudeep Kothari
- International Vaccine Institute, Seoul, Republic of Korea
| | | | | | | | | | | | - Julia A Lynch
- International Vaccine Institute, Seoul, Republic of Korea
| | - Jerome H Kim
- International Vaccine Institute, Seoul, Republic of Korea
| | - Hun Kim
- SK Chemicals, Seoul, Republic of Korea
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Wagar LE, DiFazio RM, Davis MM. Advanced model systems and tools for basic and translational human immunology. Genome Med 2018; 10:73. [PMID: 30266097 PMCID: PMC6162943 DOI: 10.1186/s13073-018-0584-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/17/2018] [Indexed: 12/31/2022] Open
Abstract
There are fundamental differences between humans and the animals we typically use to study the immune system. We have learned much from genetically manipulated and inbred animal models, but instances in which these findings have been successfully translated to human immunity have been rare. Embracing the genetic and environmental diversity of humans can tell us about the fundamental biology of immune cell types and the elasticity of the immune system. Although people are much more immunologically diverse than conventionally housed animal models, tools and technologies are now available that permit high-throughput analysis of human samples, including both blood and tissues, which will give us deep insights into human immunity in health and disease. As we gain a more detailed picture of the human immune system, we can build more sophisticated models to better reflect this complexity, both enabling the discovery of new immunological mechanisms and facilitating translation into the clinic.
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Affiliation(s)
- Lisa E Wagar
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Robert M DiFazio
- Institute for Immunity, Transplantation, and Infection, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Mark M Davis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Institute for Immunity, Transplantation, and Infection, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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Why Is Eradicating Typhoid Fever So Challenging: Implications for Vaccine and Therapeutic Design. Vaccines (Basel) 2018; 6:vaccines6030045. [PMID: 30042307 PMCID: PMC6160957 DOI: 10.3390/vaccines6030045] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 01/22/2023] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) and S. Paratyphi, namely typhoidal Salmonellae, are the cause of (para) typhoid fever, which is a devastating systemic infectious disease in humans. In addition, the spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR) S. Typhi in many low and middle-income countries poses a significant risk to human health. While currently available typhoid vaccines and therapeutics are efficacious, they have some limitations. One important limitation is the lack of controlling individuals who chronically carry S. Typhi. However, due to the strict host specificity of S. Typhi to humans, S. Typhi research is hampered. As a result, our understanding of S. Typhi pathogenesis is incomplete, thereby delaying the development and improvement of prevention and treatment strategies. Nonetheless, to better combat and contain S. Typhi, it is vital to develop a vaccine and therapy for controlling both acutely and chronically infected individuals. This review discusses how scientists are trying to combat typhoid fever, why it is so challenging to do so, which approaches show promise, and what we know about the pathogenesis of S. Typhi chronic infection.
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Fuche FJ, Jones JA, Ramachandran G, Higginson EE, Simon R, Tennant SM. Deletions in guaBA and htrA but not clpX or rfaL constitute a live-attenuated vaccine strain of Salmonella Newport to protect against serogroup C 2-C 3 Salmonella in mice. Hum Vaccin Immunother 2018; 15:1427-1435. [PMID: 29927725 PMCID: PMC6663134 DOI: 10.1080/21645515.2018.1491499] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Non-typhoidal Salmonella (NTS) are a leading cause of foodborne infections worldwide, and serogroups B, C1, C2-C3 and D are the most common serogroups associated with human disease. While live vaccine candidates that protect against S. Typhimurium (serogroup B) and S. Enteritidis (serogroup D) have been described by us and others, far less effort has been directed towards vaccines that target either serogroup C1 or C2-C3Salmonella. Here we describe a Salmonella Newport-based live-attenuated vaccine (serogroup C2-C3). Deletion of the genes clpX or rfaL, previously used in live vaccines to attenuate S. Typhimurium and/or S. Enteritidis, failed to attenuate S. Newport. However, we found that deletion of either guaBA or htrA raised the 50% lethal dose of S. Newport in an intraperitoneal infection model in BALB/c mice. Our live-attenuated vaccine candidate CVD 1966 (S. Newport ΔguaBA ΔhtrA) elicited strong antibody responses against COPS, flagellin and outer membrane proteins when administered intraperitoneally or orally. Following lethal challenge with the parental virulent strain of S. Newport, we observed vaccine efficacies of 53% for immunization via the intraperitoneal route and 47% for immunization via the oral route. Following intraperiteonal immunization, the vaccine also significantly reduced the bacterial burden of challenge organisms in the liver and spleen. Interestingly, reducing the LPS chain length by deleting rfaL did not induce a stronger immune response towards surface antigens, and failed to elicit any protection against lethal homologous challenge. In conclusion, we have developed a live-attenuated Salmonella serogroup C2-C3 vaccine that we are further evaluating.
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Affiliation(s)
- Fabien J Fuche
- a Center for Vaccine Development and Institute for Global Health, Department of Medicine , University of Maryland School of Medicine , Baltimore , MD , USA
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Roestenberg M, Hoogerwerf MA, Ferreira DM, Mordmüller B, Yazdanbakhsh M. Experimental infection of human volunteers. THE LANCET. INFECTIOUS DISEASES 2018; 18:e312-e322. [PMID: 29891332 DOI: 10.1016/s1473-3099(18)30177-4] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 02/08/2018] [Accepted: 03/01/2018] [Indexed: 12/13/2022]
Abstract
Controlled human infection (CHI) trials, in which healthy volunteers are experimentally infected, can accelerate the development of novel drugs and vaccines for infectious diseases of global importance. The use of CHI models is expanding from around 60 studies in the 1970s to more than 120 publications in this decade, primarily for influenza, rhinovirus, and malaria. CHI trials have provided landmark data for several registered drugs and vaccines, and have generated unprecedented scientific insights. Because of their invasive nature, CHI studies demand critical ethical review according to established frameworks. CHI-associated serious adverse events are rarely reported. Novel CHI models need standardised safety data from comparable CHI models to facilitate evidence-based risk assessments, as well as funds to produce challenge inoculum according to regulatory requirements. Advances such as the principle of controlled colonisation, the expansion of models to endemic areas, and the use of genetically attenuated strains will further broaden the scope of CHI trials.
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Affiliation(s)
| | | | | | - Benjamin Mordmüller
- Institute of Tropical Medicine and German Center for Infection Research, partner site Tübingen, University of Tübingen, Tübingen, Germany; Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
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Abstract
BACKGROUND Typhoid fever and paratyphoid fever continue to be important causes of illness and death, particularly among children and adolescents in south-central and southeast Asia. Two typhoid vaccines are widely available, Ty21a (oral) and Vi polysaccharide (parenteral). Newer typhoid conjugate vaccines are at varying stages of development and use. The World Health Organization has recently recommended a Vi tetanus toxoid (Vi-TT) conjugate vaccine, Typbar-TCV, as the preferred vaccine for all ages. OBJECTIVES To assess the effects of vaccines for preventing typhoid fever. SEARCH METHODS In February 2018, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, and mRCT. We also searched the reference lists of all included trials. SELECTION CRITERIA Randomized and quasi-randomized controlled trials (RCTs) comparing typhoid fever vaccines with other typhoid fever vaccines or with an inactive agent (placebo or vaccine for a different disease) in adults and children. Human challenge studies were not eligible. DATA COLLECTION AND ANALYSIS Two review authors independently applied inclusion criteria and extracted data, and assessed the certainty of the evidence using the GRADE approach. We computed vaccine efficacy per year of follow-up and cumulative three-year efficacy, stratifying for vaccine type and dose. The outcome addressed was typhoid fever, defined as isolation of Salmonella enterica serovar Typhi in blood. We calculated risk ratios (RRs) and efficacy (1 - RR as a percentage) with 95% confidence intervals (CIs). MAIN RESULTS In total, 18 RCTs contributed to the quantitative analysis in this review: 13 evaluated efficacy (Ty21a: 5 trials; Vi polysaccharide: 6 trials; Vi-rEPA: 1 trial; Vi-TT: 1 trial), and 9 reported on adverse events. All trials but one took place in typhoid-endemic countries. There was no information on vaccination in adults aged over 55 years of age, pregnant women, or travellers. Only one trial included data on children under two years of age.Ty21a vaccine (oral vaccine, three doses)A three-dose schedule of Ty21a vaccine probably prevents around half of typhoid cases during the first three years after vaccination (cumulative efficacy 2.5 to 3 years: 50%, 95% CI 35% to 61%, 4 trials, 235,239 participants, moderate-certainty evidence). These data include patients aged 3 to 44 years.Compared with placebo, this vaccine probably does not cause more vomiting, diarrhoea, nausea or abdominal pain (2 trials, 2066 participants; moderate-certainty evidence), headache, or rash (1 trial, 1190 participants; moderate-certainty evidence); however, fever (2 trials, 2066 participants; moderate-certainty evidence) is probably more common following vaccination.Vi polysaccharide vaccine (injection, one dose)A single dose of Vi polysaccharide vaccine prevents around two-thirds of typhoid cases in the first year after vaccination (year 1: 69%, 95% CI 63% to 74%; 3 trials, 99,979 participants; high-certainty evidence). In year 2, trial results were more variable, with the vaccine probably preventing between 45% and 69% of typhoid cases (year 2: 59%, 95% CI 45% to 69%; 4 trials, 194,969 participants; moderate-certainty evidence). These data included participants aged 2 to 55 years of age.The three-year cumulative efficacy of the vaccine may be around 55% (95% CI 30% to 70%; 11,384 participants, 1 trial; low-certainty evidence). These data came from a single trial conducted in South Africa in the 1980s in participants aged 5 to 15 years.Compared with placebo, this vaccine probably did not increase the incidence of fever (3 trials, 132,261 participants; moderate-certainty evidence) or erythema (3 trials, 132,261 participants; low-certainty evidence); however, swelling (3 trials, 1767 participants; moderate-certainty evidence) and pain at the injection site (1 trial, 667 participants; moderate-certainty evidence) were more common in the vaccine group.Vi-rEPA vaccine (two doses)Administration of two doses of the Vi-rEPA vaccine probably prevents between 50% and 96% of typhoid cases during the first two years after vaccination (year 1: 94%, 95% CI 75% to 99%; year 2: 87%, 95% CI 56% to 96%, 1 trial, 12,008 participants; moderate-certainty evidence). These data came from a single trial with children two to five years of age conducted in Vietnam.Compared with placebo, both the first and the second dose of this vaccine increased the risk of fever (1 trial, 12,008 and 11,091 participants, low-certainty evidence) and the second dose increase the incidence of swelling at the injection site (one trial, 11,091 participants, moderate-certainty evidence).Vi-TT vaccine (two doses)We are uncertain of the efficacy of administration of two doses of Vi-TT (PedaTyph) in typhoid cases in children during the first year after vaccination (year 1: 94%, 95% CI -1% to 100%, 1 trial, 1625 participants; very low-certainty evidence). These data come from a single cluster-randomized trial in children aged six months to 12 years and conducted in India. For single dose Vi-TT (Typbar-TCV), we found no efficacy trials evaluating the vaccine with natural exposure.There were no reported serious adverse effects in RCTs of any of the vaccines studied. AUTHORS' CONCLUSIONS The licensed Ty21a and Vi polysaccharide vaccines are efficacious in adults and children older than two years in endemic countries. The Vi-rEPA vaccine is just as efficacious, although data is only available for children. The new Vi-TT vaccine (PedaTyph) requires further evaluation to determine if it provides protection against typhoid fever. At the time of writing, there were only efficacy data from a human challenge setting in adults on the Vi-TT vaccine (Tybar), which clearly justify the ongoing field trials to evaluate vaccine efficacy.
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Affiliation(s)
- Rachael Milligan
- Liverpool School of Tropical MedicineCochrane Infectious Diseases GroupPembroke PlaceLiverpoolUKL3 5QA
| | - Mical Paul
- Rambam Health Care CampusDivision of Infectious DiseasesHa‐aliya 8 StHaifaIsrael33705
| | - Marty Richardson
- Liverpool School of Tropical MedicineCochrane Infectious Diseases GroupPembroke PlaceLiverpoolUKL3 5QA
| | - Ami Neuberger
- Rambam Health Care Campus and The Ruth and Bruce Rappaport Faculty of Medicine, Technion – Israel Institute of TechnologyDivision of Infectious DiseasesTel AvivIsrael
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Hiyoshi H, Tiffany CR, Bronner DN, Bäumler AJ. Typhoidal Salmonella serovars: ecological opportunity and the evolution of a new pathovar. FEMS Microbiol Rev 2018; 42:527-541. [DOI: 10.1093/femsre/fuy024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/19/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Hirotaka Hiyoshi
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Connor R Tiffany
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Denise N Bronner
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Andreas J Bäumler
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
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47
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Zuckerman JN, Hatz C, Kantele A. Review of current typhoid fever vaccines, cross-protection against paratyphoid fever, and the European guidelines. Expert Rev Vaccines 2018; 16:1029-1043. [PMID: 28856924 DOI: 10.1080/14760584.2017.1374861] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Typhoid and paratyphoid fever remain a global health problem, which - in non-endemic countries - are mainly seen in travelers, particularly in VFRs (visiting friends and relatives), with occasional local outbreaks occurring. A rise in anti-microbial resistance emphasizes the role of preventive measures, especially vaccinations against typhoid and paratyphoid fever for travelers visiting endemic countries. Areas covered: This state-of-the-art review recapitulates the epidemiology and mechanisms of disease of typhoid and paratyphoid fever, depicts the perspective of non-endemic countries and travelers (VFRs), and collectively presents current European recommendations for typhoid fever vaccination. We provide a brief overview of available (and developmental) vaccines in Europe, present current data on cross-protection to S. Paratyphi, and aim to provide a background for typhoid vaccine decision-making in travelers. Expert commentary: European recommendations are not harmonized. Experts must assess vaccination of travelers based on current country-specific recommendations. Travel health practitioners should be aware of the issues surrounding vaccination of travelers and be motivated to increase awareness of typhoid and paratyphoid fever risks.
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Affiliation(s)
- Jane N Zuckerman
- a Department of Infection and Immunity , Royal Free London Travel Health and Immunisation Clinic , London , UK
| | - Christoph Hatz
- b Department of Medicine and Diagnostics , Swiss Tropical and Public Health Institute , Basel , Switzerland.,c Epidemiology, Biostatistics and Prevention Institute , University of Zurich , Zurich , Switzerland
| | - Anu Kantele
- d Department of Clinical Medicine , University of Helsinki , Helsinki , Finland.,e Inflammation Center, Division of Infectious Diseases , Helsinki University Hospital , Helsinki , Finland.,f Unit of Infectious Diseases , Karolinska Institutet , Stockholm , Sweden
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Zhang Y, Brady A, Jones C, Song Y, Darton TC, Jones C, Blohmke CJ, Pollard AJ, Magder LS, Fasano A, Sztein MB, Fraser CM. Compositional and Functional Differences in the Human Gut Microbiome Correlate with Clinical Outcome following Infection with Wild-Type Salmonella enterica Serovar Typhi. mBio 2018; 9:e00686-18. [PMID: 29739901 PMCID: PMC5941076 DOI: 10.1128/mbio.00686-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 01/09/2023] Open
Abstract
Insights into disease susceptibility as well as the efficacy of vaccines against typhoid and other enteric pathogens may be informed by better understanding the relationship between the effector immune response and the gut microbiota. In the present study, we characterized the composition (16S rRNA gene profiling) and function (RNA sequencing [RNA-seq]) of the gut microbiota following immunization and subsequent exposure to wild-type Salmonella enterica serovar Typhi in a human challenge model to further investigate the central hypothesis that clinical outcomes may be linked to the gut microbiota. Metatranscriptome analysis of longitudinal stool samples collected from study subjects revealed two stable patterns of gene expression for the human gut microbiota, dominated by transcripts from either Methanobrevibacter or a diverse representation of genera in the Firmicutes phylum. Immunization with one of two live oral attenuated vaccines against S. Typhi had minimal effects on the composition or function of the gut microbiota. It was observed that subjects harboring the methanogen-dominated transcriptome community at baseline displayed a lower risk of developing symptoms of typhoid following challenge with wild-type S. Typhi. Furthermore, genes encoding antioxidant proteins, metal homeostasis and transport proteins, and heat shock proteins were expressed at a higher level at baseline or after challenge with S. Typhi in subjects who did not develop symptoms of typhoid. These data suggest that functional differences relating to redox potential and ion homeostasis in the gut microbiota may impact clinical outcomes following exposure to wild-type S. Typhi.IMPORTANCES. Typhi is a significant cause of systemic febrile morbidity in settings with poor sanitation and limited access to clean water. It has been demonstrated that the human gut microbiota can influence mucosal immune responses, but there is little information available on the impact of the human gut microbiota on clinical outcomes following exposure to enteric pathogens. Here, we describe differences in the composition and function of the gut microbiota in healthy adult volunteers enrolled in a typhoid vaccine trial and report that these differences are associated with host susceptibility to or protection from typhoid after challenge with wild-type S Typhi. Our observations have important implications in interpreting the efficacy of oral attenuated vaccines against enteric pathogens in diverse populations.
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Affiliation(s)
- Yan Zhang
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Arthur Brady
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Cheron Jones
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yang Song
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Christoph J Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Laurence S Magder
- Department of Epidemiology and Preventive Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Alessio Fasano
- Department of Pediatrics, Mucosal Immunology and Biology Research Center, Harvard Medical School, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Marcelo B Sztein
- Department of Pediatrics, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Claire M Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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49
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Baay MFD, Richie TL, Neels P. Human challenge trials in vaccine development, Rockville, MD, USA, September 28-30, 2017. Biologicals 2018; 61:85-94. [PMID: 29573967 DOI: 10.1016/j.biologicals.2018.02.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 02/21/2018] [Indexed: 11/17/2022] Open
Abstract
The International Alliance for Biological Standardization organized the second workshop on human challenge trials (HCT) in Rockville, MD, in September 2017. The objective of this meeting was to examine the use of HCT, in response to the continuing human suffering caused by infectious diseases, preventable by the development of new and improved vaccines. For this, the approach of HCT could be valuable, as HCT can provide key safety, tolerability, immunogenicity, and efficacy data, and can be used to study host-pathogen biology. HCT can generate these data with speed, efficiency and minimal expense, albeit not with the same level of robustness as clinical trials. Incorporated wisely into a clinical development plan, HCT can support optimization or down-selection of new vaccine candidates, assuring that only the worthiest candidates progress to field testing. HCT may also provide pivotal efficacy data in support of licensure, particularly when field efficacy studies are not feasible. Many aspects of HCT were discussed by the participants, including new and existing models, standardization and ethics. A consensus was achieved that HCT, if ethically justified and performed with careful attention to safety and informed consent, should be pursued to promote and accelerate vaccine development.
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Affiliation(s)
- Marc F D Baay
- P95 Pharmacovigilance and Epidemiology Services, Leuven, Belgium.
| | - Thomas L Richie
- Sanaria Institute for Global Health and Tropical Medicine, Rockville, MD, USA.
| | - Pieter Neels
- International Alliance for Biological Standardization, Lyon, France.
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Juel HB, Thomaides-Brears HB, Darton TC, Jones C, Jones E, Shrestha S, Sie R, Eustace A, Galal U, Kurupati P, Van TT, Thieu NTV, Baker S, Blohmke CJ, Pollard AJ. Salmonella Typhi Bactericidal Antibodies Reduce Disease Severity but Do Not Protect against Typhoid Fever in a Controlled Human Infection Model. Front Immunol 2018; 8:1916. [PMID: 29387052 PMCID: PMC5776093 DOI: 10.3389/fimmu.2017.01916] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 12/14/2017] [Indexed: 01/12/2023] Open
Abstract
Effective vaccines against Salmonella Typhi, a major cause of febrile illness in tropical regions, can have a significant effect as a disease control measure. Earlier work has shown that immunization with either of two Salmonella Typhi vaccines, licensed Ty21a or candidate M01ZH09, did not provide full immunity in a controlled human infection model. Here, we describe the human humoral immune responses to these oral vaccines and their functional role in protection after challenge with S. Typhi. Serum, obtained from healthy volunteers before and after vaccination with Ty21a or M01ZH09 or placebo and before and after oral challenge with wild-type S. Typhi, was assessed for bactericidal activity. Single-dose vaccination with M01ZH09 induced an increase in serum bactericidal antibodies (p = 0.001) while three doses of Ty21a did not. No association between bactericidal activity and protection against typhoid after challenge was seen in either vaccine arm. Bactericidal activity after vaccination correlated significantly with delayed disease onset (p = 0.013), lower bacterial burden (p = 0.006), and decreased disease severity scores (p = 0.021). Depletion of antibodies directed against lipopolysaccharide significantly reduced bactericidal activity (p = 0.009). We conclude that antibodies induced after ingestion of oral live-attenuated typhoid vaccines or after challenge with wild-type S. Typhi exhibit bactericidal activity. This bactericidal activity is mediated by anti-O:LPS antibodies and significantly reduces clinical symptoms but does not provide sterile immunity. This directs future vaccine studies toward other antigens or mechanisms of protection against typhoid.
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Affiliation(s)
- Helene B Juel
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.,Statens Serum Institut, Copenhagen, Denmark
| | - Helena B Thomaides-Brears
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.,Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Elizabeth Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Sonu Shrestha
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Rebecca Sie
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Andrew Eustace
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Ushma Galal
- Nuffield Department of Primary Care Health Sciences, Clinical Trials Unit, University of Oxford, Oxford, United Kingdom
| | - Prathiba Kurupati
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Tan T Van
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nga T V Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.,The Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Christoph J Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, The NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
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