1
|
Balasingam S, Dheda K, Fortune S, Gordon SB, Hoft D, Kublin JG, Loynachan CN, McShane H, Morton B, Nambiar S, Sharma NR, Robertson B, Schrager LK, Weller CL. Review of the current TB human infection studies for use in accelerating TB vaccine development: A meeting report. J Infect Dis 2024:jiae238. [PMID: 38709726 DOI: 10.1093/infdis/jiae238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024] Open
Abstract
Tools to evaluate and accelerate tuberculosis (TB) vaccine development are needed to advance global TB control strategies. Validated human infection studies for TB have the potential to facilitate breakthroughs in understanding disease pathogenesis, identify correlates of protection, develop diagnostic tools, and accelerate and de-risk vaccine and drug development. However, key challenges remain for realizing the clinical utility of these models, which require further discussion and alignment amongst key stakeholders. In March 2023, the Wellcome Trust and the International AIDS Vaccine Initiative (IAVI) convened international experts involved in developing both TB and Bacillus Calmette-Guerin (BCG) human infection studies (including mucosal and intradermal challenge routes) to discuss the status of each of the models and the key enablers to move the field forward. This report provides a summary of the presentations and discussion from the meeting. Discussions identified key issues, including demonstrating model validity, to provide confidence for vaccine developers, which may be addressed through demonstration of known vaccine effects, e.g. BCG vaccination in specific populations, and by comparing results from field efficacy and human infection studies. The workshop underscored the importance of establishing safe and acceptable studies in high-burden settings, and the need to validate more than one model to allow for different scientific questions to be addressed as well as to provide confidence to vaccine developers and regulators around use of human infection study data in vaccine development and licensure pathways.
Collapse
Affiliation(s)
| | - Keertan Dheda
- Centre for Lung Infection and Immunity, Division of Pulmonology, Department of Medicine and UCT Lung Institute & South African MRC/UCT Centre for the Study of Antimicrobial Resistance, University of Cape Town, South Africa
| | - Sarah Fortune
- Harvard T.H. Chan School of Public Health, Boston, MA
| | | | | | - James G Kublin
- Fred Hutchinson Institute, Cancer Center, Vaccine and Infectious Disease Division, US
| | | | | | - Ben Morton
- Liverpool School of Tropical Medicine, UK
| | | | | | - Brian Robertson
- Department of Infectious Disease, Imperial College London, UK
| | | | | |
Collapse
|
2
|
Shoukry NH, Cox AL, Walker CM. Immunological Monitoring in Hepatitis C Virus Controlled Human Infection Model. Clin Infect Dis 2023; 77:S270-S275. [PMID: 37579206 PMCID: PMC10425133 DOI: 10.1093/cid/ciad359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023] Open
Abstract
Controlled human infection model trials for hepatitis C virus represent an important opportunity to identify correlates of protective immunity against a well-characterized inoculum of hepatitis C virus and how such responses are modified by vaccination. In this article, we discuss the approach to immunological monitoring during such trials, including a set of recommendations for optimal sampling schedule and preferred immunological assays to examine the different arms of the immune response. We recommend that this approach be adapted to different trial designs. Finally, we discuss how these studies can provide surrogate predictors of the success of candidate vaccines.
Collapse
Affiliation(s)
- Naglaa H Shoukry
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), Montréal, Québec, Canada
- Département de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Andrea L Cox
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christopher M Walker
- Center for Vaccines and Immunity, The Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, Ohio, USA
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| |
Collapse
|
3
|
Morrison H, Jackson S, McShane H. Controlled human infection models in COVID-19 and tuberculosis: current progress and future challenges. Front Immunol 2023; 14:1211388. [PMID: 37304270 PMCID: PMC10248465 DOI: 10.3389/fimmu.2023.1211388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/09/2023] [Indexed: 06/13/2023] Open
Abstract
Controlled Human Infection Models (CHIMs) involve deliberately exposing healthy human volunteers to a known pathogen, to allow the detailed study of disease processes and evaluate methods of treatment and prevention, including next generation vaccines. CHIMs are in development for both tuberculosis (TB) and Covid-19, but challenges remain in their ongoing optimisation and refinement. It would be unethical to deliberately infect humans with virulent Mycobacteria tuberculosis (M.tb), however surrogate models involving other mycobacteria, M.tb Purified Protein Derivative or genetically modified forms of M.tb either exist or are under development. These utilise varying routes of administration, including via aerosol, per bronchoscope or intradermal injection, each with their own advantages and disadvantages. Intranasal CHIMs with SARS-CoV-2 were developed against the backdrop of the evolving Covid-19 pandemic and are currently being utilised to both assess viral kinetics, interrogate the local and systemic immunological responses post exposure, and identify immune correlates of protection. In future it is hoped they can be used to assess new treatments and vaccines. The changing face of the pandemic, including the emergence of new virus variants and increasing levels of vaccination and natural immunity within populations, has provided a unique and complex environment within which to develop a SARS-CoV-2 CHIM. This article will discuss current progress and potential future developments in CHIMs for these two globally significant pathogens.
Collapse
|
4
|
Abstract
Introduction: Despite decades of research into the development of a vaccine to combat the malaria parasite, a highly efficacious malaria vaccine is not yet available. Different whole parasite-based vaccine approaches, including deliberate Plasmodium infection and drug cure (IDC), have been evaluated in pre-clinical and early phase clinical trials. The advantage of whole parasite vaccines is that they induce immune responses against multiple parasite antigens, thus lowering the impact of antigenic diversity. Deliberate Plasmodium IDC, as a vaccine approach, involves administering infectious, live parasites in combination with an anti-malarial drug, which controls the infection and enables induction of protective immune responses.
Collapse
Affiliation(s)
- Reshma J Nevagi
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia
| | - Michael F Good
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia
| | - Danielle I Stanisic
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia
| |
Collapse
|
5
|
Nguyen LC, Bakerlee CW, McKelvey TG, Rose SM, Norman AJ, Joseph N, Manheim D, McLaren MR, Jiang S, Barnes CF, Kinniment M, Foster D, Darton TC, Morrison J. Evaluating Use Cases for Human Challenge Trials in Accelerating SARS-CoV-2 Vaccine Development. Clin Infect Dis 2021; 72:710-715. [PMID: 32628748 PMCID: PMC7454474 DOI: 10.1093/cid/ciaa935] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/02/2020] [Indexed: 01/07/2023] Open
Abstract
Human challenge trials (HCTs) have been proposed as a means to accelerate SARS-CoV-2 vaccine development. We identify and discuss three potential use cases of HCTs in the current pandemic: evaluating efficacy, converging on correlates of protection, and improving understanding of pathogenesis and the human immune response. We outline the limitations of HCTs and find that HCTs are likely to be most useful for vaccine candidates currently in preclinical stages of development. We conclude that, while currently limited in their application, there are scenarios in which HCTs would be extremely beneficial. Therefore, the option of conducting HCTs to accelerate SARS-CoV-2 vaccine development should be preserved. As HCTs require many months of preparation, we recommend an immediate effort to (1) establish guidelines for HCTs for COVID-19; (2) take the first steps toward HCTs, including preparing challenge virus and making preliminary logistical arrangements; and (3) commit to periodically re-evaluating the utility of HCTs.
Collapse
Affiliation(s)
- Linh Chi Nguyen
- Department of Politics and International Relations, University of Oxford, Oxford, United Kingdom
| | - Christopher W Bakerlee
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | | | - Sophie M Rose
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | | | - David Manheim
- Health and Risk Communication Research Center, School of Public Health, University of Haifa, Haifa, Israel
| | - Michael R McLaren
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina, USA
| | - Steven Jiang
- Harvard Law School, Cambridge, Massachusetts, USA
| | | | - Megan Kinniment
- Department of Physics, University of Oxford, Oxford, United Kingdom
| | - Derek Foster
- Rethink Priorities, Redwood City, California, USA
| | - Thomas C Darton
- Department of Infection, Immunity, and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | | |
Collapse
|
6
|
Nguyen LC, Bakerlee CW, McKelvey TG, Rose SM, Norman AJ, Joseph N, Manheim D, McLaren MR, Jiang S, Barnes CF, Kinniment M, Foster D, Darton TC, Morrison J. Evaluating Use Cases for Human Challenge Trials in Accelerating SARS-CoV-2 Vaccine Development. Clin Infect Dis 2021. [PMID: 32628748 DOI: 10.1093/cid/ciaa935/5868014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
Human challenge trials (HCTs) have been proposed as a means to accelerate SARS-CoV-2 vaccine development. We identify and discuss 3 potential use cases of HCTs in the current pandemic: evaluating efficacy, converging on correlates of protection, and improving understanding of pathogenesis and the human immune response. We outline the limitations of HCTs and find that HCTs are likely to be most useful for vaccine candidates currently in preclinical stages of development. We conclude that, while currently limited in their application, there are scenarios in which HCTs would be extremely beneficial. Therefore, the option of conducting HCTs to accelerate SARS-CoV-2 vaccine development should be preserved. As HCTs require many months of preparation, we recommend an immediate effort to (1) establish guidelines for HCTs for COVID-19; (2) take the first steps toward HCTs, including preparing challenge virus and making preliminary logistical arrangements; and (3) commit to periodically re-evaluating the utility of HCTs.
Collapse
Affiliation(s)
- Linh Chi Nguyen
- Department of Politics and International Relations, University of Oxford, Oxford, United Kingdom
| | - Christopher W Bakerlee
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | | | - Sophie M Rose
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | | | - David Manheim
- Health and Risk Communication Research Center, School of Public Health, University of Haifa, Haifa, Israel
| | - Michael R McLaren
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, North Carolina, USA
| | - Steven Jiang
- Harvard Law School, Cambridge, Massachusetts, USA
| | | | - Megan Kinniment
- Department of Physics, University of Oxford, Oxford, United Kingdom
| | - Derek Foster
- Rethink Priorities, Redwood City, California, USA
| | - Thomas C Darton
- Department of Infection, Immunity, and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | | |
Collapse
|
7
|
Nikolaou E, Jochems SP, Mitsi E, Pojar S, Blizard A, Reiné J, Solórzano C, Negera E, Carniel B, Soares-Schanoski A, Connor V, Adler H, Zaidi SR, Hales C, Hill H, Hyder-Wright A, Gordon SB, Rylance J, Ferreira DM. Experimental Human Challenge Defines Distinct Pneumococcal Kinetic Profiles and Mucosal Responses between Colonized and Non-Colonized Adults. mBio 2021; 12:e02020-20. [PMID: 33436429 DOI: 10.1128/mBio.02020-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Colonization of the upper respiratory tract with Streptococcus pneumoniae is the precursor of pneumococcal pneumonia and invasive disease. Following exposure, however, it is unclear which human immune mechanisms determine whether a pathogen will colonize. We used a human challenge model to investigate host-pathogen interactions in the first hours and days following intranasal exposure to Streptococcus pneumoniae Using a novel home sampling method, we measured early immune responses and bacterial density dynamics in the nose and saliva after volunteers were experimentally exposed to pneumococcus. Here, we show that nasal colonization can take up to 24 h to become established. Also, the following two distinct bacterial clearance profiles were associated with protection: nasal clearers with immediate clearance of bacteria in the nose by the activity of pre-existent mucosal neutrophils and saliva clearers with detectable pneumococcus in saliva at 1 h post challenge and delayed clearance mediated by an inflammatory response and increased neutrophil activity 24 h post bacterial encounter. This study describes, for the first time, how colonization with a bacterium is established in humans, signifying that the correlates of protection against pneumococcal colonization, which can be used to inform design and testing of novel vaccine candidates, could be valid for subsets of protected individuals.IMPORTANCE Occurrence of lower respiratory tract infections requires prior colonization of the upper respiratory tract with a pathogen. Most bacterial infection and colonization studies have been performed in murine and in vitro models due to the current invasive sampling methodology of the upper respiratory tract, both of which poorly reflect the complexity of host-pathogen interactions in the human nose. Self-collecting saliva and nasal lining fluid at home is a fast, low-cost, noninvasive, high-frequency sampling platform for continuous monitoring of bacterial encounter at defined time points relative to exposure. Our study demonstrates for the first time that, in humans, there are distinct profiles of pneumococcal colonization kinetics, distinguished by speed of appearance in saliva, local phagocytic function, and acute mucosal inflammatory responses, which may either recruit or activate neutrophils. These data are important for the design and testing of novel vaccine candidates.
Collapse
|
8
|
Ducarmon QR, Hoogerwerf MA, Janse JJ, Geelen AR, Koopman JPR, Zwittink RD, Goeman JJ, Kuijper EJ, Roestenberg M. Dynamics of the bacterial gut microbiota during controlled human infection with Necator americanus larvae. Gut Microbes 2020; 12:1-15. [PMID: 33222610 PMCID: PMC7714523 DOI: 10.1080/19490976.2020.1840764] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Hookworms are soil-transmitted helminths that use immune-evasive strategies to persist in the human duodenum where they are responsible for anemia and protein loss. Given their location and immune regulatory effects, hookworms likely impact the bacterial microbiota. However, microbiota studies struggle to deconvolute the effect of hookworms from confounders such as coinfections and malnutrition. We thus used an experimental human hookworm infection model to explore temporal changes in the gut microbiota before and during hookworm infection. Volunteers were dermally exposed to cumulative dosages of 50, 100 or 150 L3 Necator americanus larvae. Fecal samples were collected for microbiota profiling through 16S rRNA gene amplicon sequencing at weeks zero, four, eight, fourteen and twenty. During the acute infection phase (trial week zero to eight) no changes in bacterial diversity were detected. During the established infection phase (trial week eight to twenty), bacterial richness (Chao1, p = .0174) increased significantly over all volunteers. No relation was found between larval dosage and diversity, stability or relative abundance of individual bacterial taxa. GI symptoms were associated with an unstable microbiota during the first eight weeks and rapid recovery at week twenty. Barnesiella, amongst other taxa, was more abundant in volunteers with more GI symptoms throughout the study. In conclusion, this study showed that clinical GI symptoms following N. americanus infection are associated with temporary microbiota instability and relative abundance of specific bacterial taxa. These results suggest a possible role of hookworm-induced enteritis on microbiota stability.
Collapse
Affiliation(s)
- Q. R. Ducarmon
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, The Netherlands,Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands,CONTACT Meta Roestenberg Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands; Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - M. A. Hoogerwerf
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - J. J. Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - A. R. Geelen
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, The Netherlands,Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - J. P. R. Koopman
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - R. D. Zwittink
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, The Netherlands,Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - J. J. Goeman
- Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - E. J. Kuijper
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, The Netherlands,Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - M. Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands,Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
9
|
Jamrozik E, Selgelid MJ. Ethical issues surrounding controlled human infection challenge studies in endemic low-and middle-income countries. Bioethics 2020; 34:797-808. [PMID: 32862482 PMCID: PMC7984051 DOI: 10.1111/bioe.12802] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 05/28/2020] [Accepted: 06/03/2020] [Indexed: 05/19/2023]
Abstract
Controlled human infection challenge studies (CHIs) involve intentionally exposing research participants to, and/or thereby infecting them with, micro-organisms. There have been increased calls for more CHIs to be conducted in low- and middle-income countries (LMICs) where many relevant diseases are endemic. This article is based on a research project that identified and analyzed ethical and regulatory issues related to endemic LMIC CHIs via (a) a review of relevant literature and (b) qualitative interviews involving 45 scientists and ethicists with relevant expertise. In this article we argue that though there is an especially strong case for conducting CHIs in endemic (LMIC) settings, certain ethical issues related to the design and conduct of such studies (in such settings) nonetheless warrant particularly careful attention. We focus on ethical implications of endemic LMIC CHIs regarding (a) potential direct benefits for participants, (b) risks to participants, (c) third-party risks, (d) informed consent, (e) payment of participants, and (f) community engagement. We conclude that there is a strong ethical rationale to conduct (well-designed) CHIs in endemic LMICs, that certain ethical issues warrant particularly careful consideration, and that ethical analyses of endemic LMIC CHIs can inform current debates in research ethics more broadly.
Collapse
Affiliation(s)
- Euzebiusz Jamrozik
- Monash Bioethics CentreMonash UniversityMelbourneVictoriaAustralia
- University of Melbourne, Department of MedicineRoyal Melbourne HospitalMelbourneVictoriaAustralia
| | | |
Collapse
|
10
|
Yu M, Darton TC, Kimmelman J. Decision analysis approach to risk/benefit evaluation in the ethical review of controlled human infection studies. Bioethics 2020; 34:764-770. [PMID: 32588447 DOI: 10.1111/bioe.12773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 03/20/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Risks and benefit evaluation for controlled human infection studies, where healthy volunteers are deliberately exposed to infectious agents to evaluate vaccine efficacy, should be explicit, systematic, thorough, and non-arbitrary. Decision analysis promotes these qualities using four steps: (1) determining explicit criteria and measures for evaluation, (2) identifying alternatives to the study, (3) defining the models used to estimate the measures for each alternative, and (4) running the models to produce the estimates and compare the alternatives. In this paper, we describe how decision analysis might be applied by funders and regulators, as well as by others contemplating the use of novel controlled human infection studies for vaccine development and evaluation.
Collapse
Affiliation(s)
- Michael Yu
- Centre de Recherche du CHUM, Montreal, Canada
- Biomedical Ethics Unit/Social Studies of Medicine, McGill University, Montreal, Canada
| | - Thomas C Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, United Kingdom of Great Britain and Northern Ireland
| | - Jonathan Kimmelman
- Biomedical Ethics Unit/Social Studies of Medicine, McGill University, Montreal, Canada
| |
Collapse
|
11
|
Hoogerwerf MA, Koopman JPR, Janse JJ, Langenberg MCC, van Schuijlenburg R, Kruize YCM, Brienen EAT, Manurung MD, Verbeek-Menken P, van der Beek MT, Westra IM, Meij P, Visser LG, van Lieshout L, de Vlas SJ, Yazdanbakhsh M, Coffeng LE, Roestenberg M. A Randomized Controlled Trial to Investigate Safety and Variability of Egg Excretion After Repeated Controlled Human Hookworm Infection. J Infect Dis 2020; 223:905-913. [PMID: 32645714 DOI: 10.1093/infdis/jiaa414] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Controlled human hookworm infections could significantly contribute to the development of a hookworm vaccine. However, current models are hampered by low and unstable egg output, reducing generalizability and increasing sample sizes. This study aims to investigate the safety, tolerability, and egg output of repeated exposure to hookworm larvae. METHODS Twenty-four healthy volunteers were randomized, double-blindly, to 1, 2, or 3 doses of 50 Necator americanus L3 larvae at 2-week intervals. Volunteers were monitored weekly and were treated with albendazole at week 20. RESULTS There was no association between larval dose and number or severity of adverse events. Geometric mean egg loads stabilized at 697, 1668, and 1914 eggs per gram feces for the 1 × 50L3, 2 × 50L3, and 3 × 50L3 group, respectively. Bayesian statistical modeling showed that egg count variability relative to the mean was reduced with a second infectious dose; however, the third dose did not increase egg load or decrease variability. We therefore suggest 2 × 50L3 as an improved challenge dose. Model-based simulations indicates increased frequency of stool sampling optimizes the power of hypothetical vaccine trials. CONCLUSIONS Repeated infection with hookworm larvae increased egg counts to levels comparable to the field and reduced relative variability in egg output without aggravating adverse events. CLINICAL TRIALS REGISTRATION NCT03257072.
Collapse
Affiliation(s)
| | - Jan Pieter R Koopman
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jacqueline J Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | | | | | - Yvonne C M Kruize
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Eric A T Brienen
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Mikhael D Manurung
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Petra Verbeek-Menken
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, the Netherlands
| | - Martha T van der Beek
- Clinical Microbiology Laboratory, Leiden University Medical Center, Leiden, the Netherlands
| | - Inge M Westra
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, the Netherlands
| | - Pauline Meij
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, the Netherlands
| | - Leo G Visser
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, the Netherlands
| | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Maria Yazdanbakhsh
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Luc E Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands.,Department of Infectious Diseases, Leiden University Medical Center, Leiden, the Netherlands
| |
Collapse
|
12
|
Hoogerwerf MA, Coffeng LE, Brienen EAT, Janse JJ, Langenberg MCC, Kruize YCM, Gootjes C, Manurung MD, Dekker M, Becker L, Erkens MAA, van der Beek MT, Ganesh MS, Feijt C, Winkel BMF, Westra IM, Meij P, Loukas A, Visser LG, de Vlas SJ, Yazdanbakhsh M, van Lieshout L, Roestenberg M. New Insights Into the Kinetics and Variability of Egg Excretion in Controlled Human Hookworm Infections. J Infect Dis 2020; 220:1044-1048. [PMID: 31077279 DOI: 10.1093/infdis/jiz218] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/10/2019] [Indexed: 12/29/2022] Open
Abstract
Four healthy volunteers were infected with 50 Necator americanus infective larvae (L3) in a controlled human hookworm infection trial and followed for 52 weeks. The kinetics of fecal egg counts in volunteers was assessed with Bayesian multilevel analysis, which revealed an increase between weeks 7 and 13, followed by an egg density plateau of about 1000 eggs/g of feces. Variation in egg counts was minimal between same-day measurements but varied considerably between days, particularly during the plateau phase. These analyses pave the way for the controlled human hookworm model to accelerate drug and vaccine efficacy studies.
Collapse
Affiliation(s)
| | - Luc E Coffeng
- Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Eric A T Brienen
- Department of Parasitology, Leiden University Medical Center, Leiden
| | | | | | - Yvonne C M Kruize
- Department of Parasitology, Leiden University Medical Center, Leiden
| | - Chelsea Gootjes
- Department of Parasitology, Leiden University Medical Center, Leiden
| | | | - Mark Dekker
- Department of Parasitology, Leiden University Medical Center, Leiden
| | - Luke Becker
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns
| | | | | | - Munisha S Ganesh
- Department of Parasitology, Leiden University Medical Center, Leiden
| | - Carola Feijt
- Department of Parasitology, Leiden University Medical Center, Leiden
| | | | - Inge M Westra
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden
| | - Pauline Meij
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns
| | - Leo G Visser
- Department of Infectious Diseases, Leiden University Medical Center, Leiden
| | - Sake J de Vlas
- Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | | | | | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden.,Department of Infectious Diseases, Leiden University Medical Center, Leiden
| |
Collapse
|
13
|
Scholzen A, Sauerwein RW. Immune activation and induction of memory: lessons learned from controlled human malaria infection with Plasmodium falciparum. Parasitology 2016; 143:224-35. [PMID: 26864135 DOI: 10.1017/S0031182015000761] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Controlled human malaria infections (CHMIs) are a powerful tool to assess the efficacy of drugs and/or vaccine candidates, but also to study anti-malarial immune responses at well-defined time points after infection. In this review, we discuss the insights that CHMI trials have provided into early immune activation and regulation during acute infection, and the capacity to induce and maintain immunological memory. Importantly, these studies show that a single infection is sufficient to induce long-lasting parasite-specific T- and B-cell memory responses, and suggest that blood-stage induced regulatory responses can limit inflammation both in ongoing and potentially future infections. As future perspective of investigation in CHMIs, we discuss the role of innate cell subsets, the interplay between innate and adaptive immune activation and the potential modulation of these responses after natural pre-exposure.
Collapse
|
14
|
Waddington CS, Darton TC, Jones C, Haworth K, Peters A, John T, Thompson BAV, Kerridge SA, Kingsley RA, Zhou L, Holt KE, Yu LM, Lockhart S, Farrar JJ, Sztein MB, Dougan G, Angus B, Levine MM, Pollard AJ. An outpatient, ambulant-design, controlled human infection model using escalating doses of Salmonella Typhi challenge delivered in sodium bicarbonate solution. Clin Infect Dis 2014; 58:1230-40. [PMID: 24519873 PMCID: PMC3982839 DOI: 10.1093/cid/ciu078] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Oral delivery of escalating-dose Salmonella Typhi (Quailes strain) using sodium bicarbonate buffer solution in an outpatient, ambulant-design human infection study demonstrates safety, requires a lower challenge inoculum than that used in historical studies, and offers a unique insight into host–pathogen interactions. Background. Typhoid fever is a major global health problem, the control of which is hindered by lack of a suitable animal model in which to study Salmonella Typhi infection. Until 1974, a human challenge model advanced understanding of typhoid and was used in vaccine development. We set out to establish a new human challenge model and ascertain the S. Typhi (Quailes strain) inoculum required for an attack rate of 60%–75% in typhoid-naive volunteers when ingested with sodium bicarbonate solution. Methods. Groups of healthy consenting adults ingested escalating dose levels of S. Typhi and were closely monitored in an outpatient setting for 2 weeks. Antibiotic treatment was initiated if typhoid diagnosis occurred (temperature ≥38°C sustained ≥12 hours or bacteremia) or at day 14 in those remaining untreated. Results. Two dose levels (103 or 104 colony-forming units) were required to achieve the primary objective, resulting in attack rates of 55% (11/20) or 65% (13/20), respectively. Challenge was well tolerated; 4 of 40 participants fulfilled prespecified criteria for severe infection. Most diagnoses (87.5%) were confirmed by blood culture, and asymptomatic bacteremia and stool shedding of S. Typhi was also observed. Participants who developed typhoid infection demonstrated serological responses to flagellin and lipopolysaccharide antigens by day 14; however, no anti-Vi antibody responses were detected. Conclusions. Human challenge with a small inoculum of virulent S. Typhi administered in bicarbonate solution can be performed safely using an ambulant-model design to advance understanding of host–pathogen interactions and immunity. This model should expedite development of diagnostics, vaccines, and therapeutics for typhoid control.
Collapse
|