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Tian X, Janes HE, Kublin JG. Statistical design and analysis of controlled human malaria infection trials. Malar J 2024; 23:133. [PMID: 38702775 PMCID: PMC11068571 DOI: 10.1186/s12936-024-04959-2] [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: 05/01/2023] [Accepted: 04/22/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Malaria is a potentially life-threatening disease caused by Plasmodium protozoa transmitted by infected Anopheles mosquitoes. Controlled human malaria infection (CHMI) trials are used to assess the efficacy of interventions for malaria elimination. The operating characteristics of statistical methods for assessing the ability of interventions to protect individuals from malaria is uncertain in small CHMI studies. This paper presents simulation studies comparing the performance of a variety of statistical methods for assessing efficacy of intervention in CHMI trials. METHODS Two types of CHMI designs were investigated: the commonly used single high-dose design (SHD) and the repeated low-dose design (RLD), motivated by simian immunodeficiency virus (SIV) challenge studies. In the context of SHD, the primary efficacy endpoint is typically time to infection. Using a continuous time survival model, five statistical tests for assessing the extent to which an intervention confers partial or full protection under single dose CHMI designs were evaluated. For RLD, the primary efficacy endpoint is typically the binary infection status after a specific number of challenges. A discrete time survival model was used to study the characteristics of RLD versus SHD challenge studies. RESULTS In a SHD study with the continuous time survival model, log-rank test and t-test are the most powerful and provide more interpretable results than Wilcoxon rank-sum tests and Lachenbruch tests, while the likelihood ratio test is uniformly most powerful but requires knowledge of the underlying probability model. In the discrete time survival model setting, SHDs are more powerful for assessing the efficacy of an intervention to prevent infection than RLDs. However, additional information can be inferred from RLD challenge designs, particularly using a likelihood ratio test. CONCLUSIONS Different statistical methods can be used to analyze controlled human malaria infection (CHMI) experiments, and the choice of method depends on the specific characteristics of the experiment, such as the sample size allocation between the control and intervention groups, and the nature of the intervention. The simulation results provide guidance for the trade off in statistical power when choosing between different statistical methods and study designs.
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Affiliation(s)
- Xiaowen Tian
- Department of Biostatistics, University of Washington, 3980 15th Ave NE, Seattle, WA, 98195, USA.
| | - Holly E Janes
- Department of Biostatistics, University of Washington, 3980 15th Ave NE, Seattle, WA, 98195, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
| | - James G Kublin
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
- Department of Global Health, University of Washington, 3980 15th Ave NE, Seattle, WA, 98195, USA
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Chavtur C, Staubus WJ, Ho M, Hergott DEB, Seilie AM, Healy S, Duffy P, Jackson L, Talley A, Kappe SHI, Hoffman SL, Richie TL, Kublin JG, Chang M, Murphy SC. Plasmodium 18S Ribosomal RNA Biomarker Clearance After Food and Drug Administration-Approved Antimalarial Treatment in Controlled Human Malaria Infection Trials. Open Forum Infect Dis 2023; 10:ofad202. [PMID: 37265668 PMCID: PMC10230565 DOI: 10.1093/ofid/ofad202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/12/2023] [Indexed: 06/03/2023] Open
Abstract
Background Sensitive molecular assays, such as quantitative reverse-transcription polymerase chain reaction (qRT-PCR) of Plasmodium 18S ribosomal RNA (rRNA), are increasingly the primary method of detecting infections in controlled human malaria infection (CHMI) trials. However, thick blood smears (TBSs) remain the main method for confirming clearance of parasites after curative treatment, in part owing to uncertainty regarding biomarker clearance rates. Methods For this analysis, 18S rRNA qRT-PCR data were compiled from 127 Plasmodium falciparum-infected participants treated with chloroquine or atovaquone-proguanil in 6 CHMI studies conducted in Seattle, Washington, over the past decade. A survival analysis approach was used to compare biomarker and TBS clearance times among studies. The effect of the parasite density at which treatment was initiated on clearance time was estimated using linear regression. Results The median time to biomarker clearance was 3 days (interquartile range, 3-5 days), while the median time to TBS clearance was 1 day (1-2 days). Time to biomarker clearance increased with the parasite density at which treatment was initiated. Parasite density did not have a significant effect on TBS clearance. Conclusions The Plasmodium 18S rRNA biomarker clears quickly and can be relied on to confirm the adequacy of Food and Drug Administration-approved treatments in CHMI studies at nonendemic sites.
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Affiliation(s)
- Chris Chavtur
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Weston J Staubus
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Mabel Ho
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Dianna E B Hergott
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, USA
| | - Annette M Seilie
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Sara Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Patrick Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Lisa Jackson
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington, USA
| | | | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | | | | | - James G Kublin
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Ming Chang
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Sean C Murphy
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Department of Microbiology, University of Washington, Seattle, Washington, USA
- Department of Laboratories, Seattle Children's Hospital, Seattle, Washington, USA
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3
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Choy RKM, Bourgeois AL, Ockenhouse CF, Walker RI, Sheets RL, Flores J. Controlled Human Infection Models To Accelerate Vaccine Development. Clin Microbiol Rev 2022; 35:e0000821. [PMID: 35862754 PMCID: PMC9491212 DOI: 10.1128/cmr.00008-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The timelines for developing vaccines against infectious diseases are lengthy, and often vaccines that reach the stage of large phase 3 field trials fail to provide the desired level of protective efficacy. The application of controlled human challenge models of infection and disease at the appropriate stages of development could accelerate development of candidate vaccines and, in fact, has done so successfully in some limited cases. Human challenge models could potentially be used to gather critical information on pathogenesis, inform strain selection for vaccines, explore cross-protective immunity, identify immune correlates of protection and mechanisms of protection induced by infection or evoked by candidate vaccines, guide decisions on appropriate trial endpoints, and evaluate vaccine efficacy. We prepared this report to motivate fellow scientists to exploit the potential capacity of controlled human challenge experiments to advance vaccine development. In this review, we considered available challenge models for 17 infectious diseases in the context of the public health importance of each disease, the diversity and pathogenesis of the causative organisms, the vaccine candidates under development, and each model's capacity to evaluate them and identify correlates of protective immunity. Our broad assessment indicated that human challenge models have not yet reached their full potential to support the development of vaccines against infectious diseases. On the basis of our review, however, we believe that describing an ideal challenge model is possible, as is further developing existing and future challenge models.
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Affiliation(s)
- Robert K. M. Choy
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | - A. Louis Bourgeois
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | | | - Richard I. Walker
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | | | - Jorge Flores
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
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Murphy SC, Vaughan AM, Kublin JG, Fishbauger M, Seilie AM, Cruz KP, Mankowski T, Firat M, Magee S, Betz W, Kain H, Camargo N, Haile MT, Armstrong J, Fritzen E, Hertoghs N, Kumar S, Sather DN, Pinder LF, Deye GA, Galbiati S, Geber C, Butts J, Jackson LA, Kappe SH. A genetically engineered Plasmodium falciparum parasite vaccine provides protection from controlled human malaria infection. Sci Transl Med 2022; 14:eabn9709. [PMID: 36001680 PMCID: PMC10423335 DOI: 10.1126/scitranslmed.abn9709] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Genetically engineered live Plasmodium falciparum sporozoites constitute a potential platform for creating consistently attenuated, genetically defined, whole-parasite vaccines against malaria through targeted gene deletions. Such genetically attenuated parasites (GAPs) do not require attenuation by irradiation or concomitant drug treatment. We previously developed a P. falciparum (Pf) GAP with deletions in P52, P36, and SAP1 genes (PfGAP3KO) and demonstrated its safety and immunogenicity in humans. Here, we further assessed safety, tolerability, and immunogenicity of the PfGAP3KO vaccine and tested its efficacy against controlled human malaria infection (CHMI) in malaria-naïve subjects. The vaccine was delivered by three (n = 6) or five (n = 8) immunizations with ~200 PfGAP3KO-infected mosquito bites per immunization. PfGAP3KO was safe and well tolerated with no breakthrough P. falciparum blood stage infections. Vaccine-related adverse events were predominately localized urticaria related to the numerous mosquito bites administered per vaccination. CHMI via bites with mosquitoes carrying fully infectious Pf NF54 parasites was carried out 1 month after the last immunization. Half of the study participants who received either three or five PfGAP3KO immunizations remained P. falciparum blood stage negative, as shown by a lack of detection of Plasmodium 18S rRNA in the blood for 28 days after CHMI. Six protected study participants received a second CHMI 6 months later, and one remained completely protected. Thus, the PfGAP3KO vaccine was safe and immunogenic and was capable of inducing protection against sporozoite infection. These results warrant further evaluation of PfGAP3KO vaccine efficacy in dose-range finding trials with an injectable formulation.
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Affiliation(s)
- Sean C. Murphy
- Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington; Seattle, WA 98109
- Department of Microbiology, University of Washington; Seattle, WA 98109
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
- Department of Pediatrics, University of Washington; Seattle, WA 98105
| | - James G. Kublin
- Department of Global Health, University of Washington; Seattle, WA 98195
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center; Seattle, WA 98109
| | - Matthew Fishbauger
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Annette M. Seilie
- Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington; Seattle, WA 98109
| | - Kurtis P. Cruz
- Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington; Seattle, WA 98109
| | - Tracie Mankowski
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Melike Firat
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Sara Magee
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Will Betz
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Heather Kain
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Nelly Camargo
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Meseret T. Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Janna Armstrong
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Emma Fritzen
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Nina Hertoghs
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - D. Noah Sather
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Leeya F. Pinder
- Department of Obstetrics and Gynecology, University of Washington; Seattle, WA 98195
| | - Gregory A. Deye
- Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health; Bethesda, MD, United States
| | | | - Casey Geber
- The Emmes Company; Rockville, MD, United States
| | | | - Lisa A. Jackson
- Kaiser Permanente Washington Health Research Institute; Seattle, WA
| | - Stefan H.I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
- Department of Global Health, University of Washington; Seattle, WA 98195
- Department of Pediatrics, University of Washington; Seattle, WA 98105
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5
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Shibeshi W, Bagchus W, Yalkinoglu Ö, Tappert A, Engidawork E, Oeuvray C. Reproducibility of malaria sporozoite challenge model in humans for evaluating efficacy of vaccines and drugs: a systematic review. BMC Infect Dis 2021; 21:1274. [PMID: 34930178 PMCID: PMC8686662 DOI: 10.1186/s12879-021-06953-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/06/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The development of novel malaria vaccines and antimalarial drugs is limited partly by emerging challenges to conduct field trials in malaria endemic areas, including unknown effects of existing immunity and a reported fall in malaria incidence. As a result, Controlled Human Malaria Infection (CHMI) has become an important approach for accelerated development of malarial vaccines and drugs. We conducted a systematic review of the literature to establish aggregate evidence on the reproducibility of a malaria sporozoite challenge model. METHODS A systematic review of research articles published between 1990 and 2018 on efficacy testing of malaria vaccines and drugs using sporozoite challenge and sporozoite infectivity studies was conducted using Pubmed, Scopus, Embase and Cochrane Library, ClinicalTrials.gov and Trialtrove. The inclusion criteria were randomized and non-randomized, controlled or open-label trials using P. falciparum or P. vivax sporozoite challenges. The data were extracted from articles using standardized data extraction forms and descriptive analysis was performed for evidence synthesis. The endpoints considered were infectivity, prepatent period, parasitemia and safety of sporozoite challenge. RESULTS Seventy CHMI trials conducted with a total of 2329 adult healthy volunteers were used for analysis. CHMI was induced by bites of mosquitoes infected with P. falciparum or P. vivax in 52 trials and by direct venous inoculation of P. falciparum sporozoites (PfSPZ challenge) in 18 trials. Inoculation with P. falciparum-infected mosquitoes produced 100% infectivity in 40 studies and the mean/median prepatent period assessed by thick blood smear (TBS) microscopy was ≤ 12 days in 24 studies. On the other hand, out of 12 infectivity studies conducted using PfSPZ challenge, 100% infection rate was reproduced in 9 studies with a mean or median prepatent period of 11 to 15.3 days as assessed by TBS and 6.8 to 12.6 days by PCR. The safety profile of P. falciparum and P.vivax CHMI was characterized by consistent features of malaria infection. CONCLUSION There is ample evidence on consistency of P. falciparum CHMI models in terms of infectivity and safety endpoints, which supports applicability of CHMI in vaccine and drug development. PfSPZ challenge appears more feasible for African trials based on current evidence of safety and efficacy.
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Affiliation(s)
- Workineh Shibeshi
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
- Global Health Institute of Merck, Ares Trading S.A., A subsidiary of Merck KGaA, Darmstadt, Germany.
| | - Wilhelmina Bagchus
- Translational Medicine, Merck Serono S.A., An Affiliate of Merck KGaA, Darmstadt, Germany
| | - Özkan Yalkinoglu
- Translational Medicine, Merck Healthcare KGaA, Darmstadt, Germany
| | - Aliona Tappert
- Global Patient Safety, Merck Healthcare KGaA, Darmstadt, Germany
| | - Ephrem Engidawork
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Claude Oeuvray
- Global Health Institute of Merck, Ares Trading S.A., A subsidiary of Merck KGaA, Darmstadt, Germany
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6
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Wang CYT, Ballard EL, Pava Z, Marquart L, Gaydon J, Murphy SC, Whiley D, O'Rourke P, McCarthy JS. Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults. Malar J 2021; 20:181. [PMID: 33838672 PMCID: PMC8035755 DOI: 10.1186/s12936-021-03717-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 03/29/2021] [Indexed: 11/10/2022] Open
Abstract
Background Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. Methods A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. Results The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. Conclusions The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03717-y.
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Affiliation(s)
- Claire Y T Wang
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia. .,Child Health Research Centre, The University of Queensland, Brisbane, Australia.
| | - Emma L Ballard
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Zuleima Pava
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jane Gaydon
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,Child Health Research Centre, The University of Queensland, Brisbane, Australia
| | - Sean C Murphy
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, WA, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - David Whiley
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Peter O'Rourke
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Medicine, The University of Queensland, Brisbane, Australia
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7
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Genotyping cognate Plasmodium falciparum in humans and mosquitoes to estimate onward transmission of asymptomatic infections. Nat Commun 2021; 12:909. [PMID: 33568678 PMCID: PMC7875998 DOI: 10.1038/s41467-021-21269-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/15/2021] [Indexed: 01/30/2023] Open
Abstract
Malaria control may be enhanced by targeting reservoirs of Plasmodium falciparum transmission. One putative reservoir is asymptomatic malaria infections and the scale of their contribution to transmission in natural settings is not known. We assess the contribution of asymptomatic malaria to onward transmission using a 14-month longitudinal cohort of 239 participants in a high transmission site in Western Kenya. We identify P. falciparum in asymptomatically- and symptomatically-infected participants and naturally-fed mosquitoes from their households, genotype all parasites using deep sequencing of the parasite genes pfama1 and pfcsp, and use haplotypes to infer participant-to-mosquito transmission through a probabilistic model. In 1,242 infections (1,039 in people and 203 in mosquitoes), we observe 229 (pfcsp) and 348 (pfama1) unique parasite haplotypes. Using these to link human and mosquito infections, compared with symptomatic infections, asymptomatic infections more than double the odds of transmission to a mosquito among people with both infection types (Odds Ratio: 2.56; 95% Confidence Interval (CI): 1.36-4.81) and among all participants (OR 2.66; 95% CI: 2.05-3.47). Overall, 94.6% (95% CI: 93.1-95.8%) of mosquito infections likely resulted from asymptomatic infections. In high transmission areas, asymptomatic infections are the major contributor to mosquito infections and may be targeted as a component of transmission reduction.
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Chughlay MF, Akakpo S, Odedra A, Csermak-Renner K, Djeriou E, Winnips C, Leboulleux D, Gaur AH, Shanks GD, McCarthy J, Chalon S. Liver Enzyme Elevations in Plasmodium falciparum Volunteer Infection Studies: Findings and Recommendations. Am J Trop Med Hyg 2020; 103:378-393. [PMID: 32314694 PMCID: PMC7356411 DOI: 10.4269/ajtmh.19-0846] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Malaria volunteer infection studies (VISs) accelerate new drug and vaccine development. In the induced blood-stage malaria (IBSM) model, volunteers are inoculated with erythrocytes infected with Plasmodium falciparum. Observations of elevated liver enzymes in the IBSM model with new chemical entities (NCEs) promoted an analysis of available data. Data were reviewed from eight IBSM studies of seven different NCEs, plus two studies with the registered antimalarial piperaquine conducted between June 2013 and January 2017 at QIMR Berghofer, Brisbane, Australia. Alanine aminotransferase (ALT) was elevated (> 2.5 times the upper limit of normal [×ULN]) in 20/114 (17.5%) participants. Of these, 8.9% (10/114) had moderate increases (> 2.5–5 × ULN), noted in seven studies of six different NCEs ± piperaquine or piperaquine alone, and 8.9% (10/114) had severe elevations (> 5 × ULN), occurring in six studies of six different NCEs ± piperaquine. Aspartate aminotransferase (AST) was elevated (> 2.5 × ULN) in 11.4% (13/114) of participants, across six of the 10 studies. Bilirubin was > 2 × ULN in one participant. Published data from other VIS models, using sporozoite inoculation by systemic administration or mosquito feeding, also showed moderate/severe liver enzyme elevations. In conclusion, liver enzyme elevations in IBSM studies are most likely multifactorial and could be caused by the model conditions, that is, malaria infection/parasite density and/or effective parasite clearance, or by participant-specific risk factors, acetaminophen administration, or direct hepatotoxicity of the test drug. We make recommendations that may mitigate the risk of liver enzyme elevations in future VISs and propose measures to assist their interpretation, should they occur.
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Affiliation(s)
| | | | - Anand Odedra
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | | | | | | | | | - Aditya H Gaur
- St. Jude Children's Research Hospital, Memphis, Tennessee
| | - G Dennis Shanks
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - James McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
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9
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Seilie AM, Chang M, Hanron AE, Billman ZP, Stone BC, Zhou K, Olsen TM, Daza G, Ortega J, Cruz KR, Smith N, Healy SA, Neal J, Wallis CK, Shelton L, Mankowski TV, Wong-Madden S, Mikolajczak SA, Vaughan AM, Kappe SHI, Fishbaugher M, Betz W, Kennedy M, Hume JCC, Talley AK, Hoffman SL, Chakravarty S, Sim BKL, Richie TL, Wald A, Plowe CV, Lyke KE, Adams M, Fahle GA, Cowan EP, Duffy PE, Kublin JG, Murphy SC. Beyond Blood Smears: Qualification of Plasmodium 18S rRNA as a Biomarker for Controlled Human Malaria Infections. Am J Trop Med Hyg 2020; 100:1466-1476. [PMID: 31017084 PMCID: PMC6553913 DOI: 10.4269/ajtmh.19-0094] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
18S rRNA is a biomarker that provides an alternative to thick blood smears in controlled human malaria infection (CHMI) trials. We reviewed data from CHMI trials at non-endemic sites that used blood smears and Plasmodium 18S rRNA/rDNA biomarker nucleic acid tests (NATs) for time to positivity. We validated a multiplex quantitative reverse transcription–polymerase chain reaction (qRT-PCR) for Plasmodium 18S rRNA, prospectively compared blood smears and qRT-PCR for three trials, and modeled treatment effects at different biomarker-defined parasite densities to assess the impact on infection detection, symptom reduction, and measured intervention efficacy. Literature review demonstrated accelerated NAT-based infection detection compared with blood smears (mean acceleration: 3.2–3.6 days). For prospectively tested trials, the validated Plasmodium 18S rRNA qRT-PCR positivity was earlier (7.6 days; 95% CI: 7.1–8.1 days) than blood smears (11.0 days; 95% CI: 10.3–11.8 days) and significantly preceded the onset of grade 2 malaria-related symptoms (12.2 days; 95% CI: 10.6–13.3 days). Discrepant analysis showed that the risk of a blood smear–positive, biomarker-negative result was negligible. Data modeling predicted that treatment triggered by specific biomarker-defined thresholds can differentiate complete, partial, and non-protective outcomes and eliminate many grade 2 and most grade 3 malaria-related symptoms post-CHMI. Plasmodium 18S rRNA is a sensitive and specific biomarker that can justifiably replace blood smears for infection detection in CHMI trials in non-endemic settings. This study led to biomarker qualification through the U.S. Food and Drug Administration for use in CHMI studies at non-endemic sites, which will facilitate biomarker use for the qualified context of use in drug and vaccine trials.
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Affiliation(s)
- Annette M Seilie
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Ming Chang
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Amelia E Hanron
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Zachary P Billman
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Brad C Stone
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Kevin Zhou
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Tayla M Olsen
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Glenda Daza
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Jose Ortega
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Kurtis R Cruz
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Nahum Smith
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Sara A Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,Division of Pediatric Infectious Diseases, Department of Pediatrics, University of Washington, Seattle, Washington.,Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Jillian Neal
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Carolyn K Wallis
- Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
| | - Lisa Shelton
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Tracie VonGoedert Mankowski
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Sharon Wong-Madden
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Sebastian A Mikolajczak
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Ashley M Vaughan
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Matt Fishbaugher
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Will Betz
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Mark Kennedy
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | - Jen C C Hume
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Angela K Talley
- Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington
| | | | | | | | | | - Anna Wald
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| | | | - Kirsten E Lyke
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Matthew Adams
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gary A Fahle
- Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | | | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - James G Kublin
- Seattle Malaria Clinical Trials Center, Fred Hutch Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Sean C Murphy
- Department of Microbiology, University of Washington, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutch Cancer Research Center, Seattle, Washington.,Center for Global Infectious Disease Research, Seattle Children's Research Institute (formerly the Center for Infectious Disease Research), Seattle, Washington.,Department of Laboratory Medicine, Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington
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10
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Healy SA, Murphy SC, Hume JCC, Shelton L, Kuntz S, Van Voorhis WC, Moodie Z, Metch B, Wang R, Silver-Brace T, Fishbaugher M, Kennedy M, Finney OC, Chaturvedi R, Marcsisin SR, Hobbs CV, Warner-Lubin M, Talley AK, Wong-Madden S, Stuart K, Wald A, Kappe SH, Kublin JG, Duffy PE. Chemoprophylaxis Vaccination: Phase I Study to Explore Stage-specific Immunity to Plasmodium falciparum in US Adults. Clin Infect Dis 2019; 71:1481-1490. [PMID: 31621832 PMCID: PMC7486848 DOI: 10.1093/cid/ciz1010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/11/2019] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Chemoprophylaxis vaccination with sporozoites (CVac) with chloroquine induces protection against a homologous Plasmodium falciparum sporozoite (PfSPZ) challenge, but whether blood-stage parasite exposure is required for protection remains unclear. Chloroquine suppresses and clears blood-stage parasitemia, while other antimalarial drugs, such as primaquine, act against liver-stage parasites. Here, we evaluated CVac regimens using primaquine and/or chloroquine as the partner drug to discern whether blood-stage parasite exposure impacts protection against homologous controlled human malaria infection. METHODS In a Phase I, randomized, partial double-blind, placebo-controlled study of 36 malaria-naive adults, all CVac subjects received chloroquine prophylaxis and bites from 12-15 P. falciparum-infected mosquitoes (CVac-chloroquine arm) at 3 monthly iterations, and some received postexposure primaquine (CVac-primaquine/chloroquine arm). Drug control subjects received primaquine, chloroquine, and uninfected mosquito bites. After a chloroquine washout, subjects, including treatment-naive infectivity controls, underwent homologous, PfSPZ controlled human malaria infection and were monitored for parasitemia for 21 days. RESULTS No serious adverse events occurred. During CVac, all but 1 subject in the study remained blood-smear negative, while only 1 subject (primaquine/chloroquine arm) remained polymerase chain reaction-negative. Upon challenge, compared to infectivity controls, 3/3 chloroquine arm subjects displayed delayed patent parasitemia (P = .01) but not sterile protection, while 3/11 primaquine/chloroquine subjects remained blood-smear negative. CONCLUSIONS CVac-primaquine/chloroquine is safe and induces sterile immunity to P. falciparum in some recipients, but a single 45 mg dose of primaquine postexposure does not completely prevent blood-stage parasitemia. Unlike previous studies, CVac-chloroquine did not produce sterile immunity. CLINICAL TRIALS REGISTRATION NCT01500980.
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Affiliation(s)
- Sara A Healy
- Center for Infectious Disease Research, Seattle, Washington, USA,Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Washington, Seattle, Washington, USA,Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Sean C Murphy
- Center for Infectious Disease Research, Seattle, Washington, USA,Department of Laboratory Medicine and Microbiology, University of Washington, Seattle, Washington, USA,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Jen C C Hume
- Center for Infectious Disease Research, Seattle, Washington, USA,Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Lisa Shelton
- Center for Infectious Disease Research, Seattle, Washington, USA
| | - Steve Kuntz
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Wesley C Van Voorhis
- Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA,Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Zoe Moodie
- Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Barbara Metch
- Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Ruobing Wang
- Center for Infectious Disease Research, Seattle, Washington, USA
| | | | | | - Mark Kennedy
- Center for Infectious Disease Research, Seattle, Washington, USA
| | - Olivia C Finney
- Center for Infectious Disease Research, Seattle, Washington, USA
| | - Richa Chaturvedi
- Center for Infectious Disease Research, Seattle, Washington, USA
| | - Sean R Marcsisin
- Military Malaria Research Program, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Charlotte V Hobbs
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Margaret Warner-Lubin
- Center for Infectious Disease Research, Seattle, Washington, USA,C3 Research Associates, Seattle, Washington, USA
| | - Angela K Talley
- Center for Infectious Disease Research, Seattle, Washington, USA
| | - Sharon Wong-Madden
- Center for Infectious Disease Research, Seattle, Washington, USA,Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Ken Stuart
- Center for Infectious Disease Research, Seattle, Washington, USA
| | - Anna Wald
- Department of Laboratory Medicine and Microbiology, University of Washington, Seattle, Washington, USA,Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA,Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA,Department of Epidemiology, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Stefan H Kappe
- Center for Infectious Disease Research, Seattle, Washington, USA
| | - James G Kublin
- Center for Infectious Disease Research, Seattle, Washington, USA,Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Patrick E Duffy
- Center for Infectious Disease Research, Seattle, Washington, USA,Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA,Correspondence: P. E. Duffy, 29 Lincoln Drive, Building 29B, Bethesda, MD, 20892 ()
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11
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Murphy SC, Duke ER, Shipman KJ, Jensen RL, Fong Y, Ferguson S, Janes HE, Gillespie K, Seilie AM, Hanron AE, Rinn L, Fishbaugher M, VonGoedert T, Fritzen E, Kappe SH, Chang M, Sousa JC, Marcsisin SR, Chalon S, Duparc S, Kerr N, Möhrle JJ, Andenmatten N, Rueckle T, Kublin JG. A Randomized Trial Evaluating the Prophylactic Activity of DSM265 Against Preerythrocytic Plasmodium falciparum Infection During Controlled Human Malarial Infection by Mosquito Bites and Direct Venous Inoculation. J Infect Dis 2019; 217:693-702. [PMID: 29216395 DOI: 10.1093/infdis/jix613] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/29/2017] [Indexed: 11/13/2022] Open
Abstract
Background DSM265 is a selective inhibitor of Plasmodium dihydroorotate dehydrogenase that fully protected against controlled human malarial infection (CHMI) by direct venous inoculation of Plasmodium falciparum sporozoites when administered 1 day before challenge and provided partial protection when administered 7 days before challenge. Methods A double-blinded, randomized, placebo-controlled trial was performed to assess safety, tolerability, pharmacokinetics, and efficacy of 1 oral dose of 400 mg of DSM265 before CHMI. Three cohorts were studied, with DSM265 administered 3 or 7 days before direct venous inoculation of sporozoites or 7 days before 5 bites from infected mosquitoes. Results DSM265-related adverse events consisted of mild-to-moderate headache and gastrointestinal symptoms. DSM265 concentrations were consistent with pharmacokinetic models (mean area under the curve extrapolated to infinity, 1707 µg*h/mL). Placebo-treated participants became positive by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and were treated 7-10 days after CHMI. Among DSM265-treated subjects, 2 of 6 in each cohort were sterilely protected. DSM265-treated recipients had longer times to development of parasitemia than placebo-treated participants (P < .004). Conclusions This was the first CHMI study of a novel antimalarial compound to compare direct venous inoculation of sporozoites and mosquito bites. Times to qRT-PCR positivity and treatment were comparable for both routes. DSM265 given 3 or 7 days before CHMI was safe and well tolerated but sterilely protected only one third of participants.
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Affiliation(s)
- Sean C Murphy
- Department of Laboratory Medicine, University of Washington, Seattle, Washington.,Department of Microbiology, University of Washington, Seattle, Washington.,Center for Emerging and Re-emerging Infectious Diseases, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Elizabeth R Duke
- Department of Medicine, University of Washington, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Kelly J Shipman
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Ryan L Jensen
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Youyi Fong
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Sue Ferguson
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Holly E Janes
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Kevin Gillespie
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Annette M Seilie
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Amelia E Hanron
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Laurie Rinn
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Matthew Fishbaugher
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Tracie VonGoedert
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Emma Fritzen
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Stefan H Kappe
- Human Challenge Center, Center for Infectious Disease Research, Seattle, Washington
| | - Ming Chang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Jason C Sousa
- Walter Reed Army Institute of Research, Silver Spring, Maryland
| | | | | | | | - Nicola Kerr
- Medicines for Malaria Venture, Geneva, Switzerland
| | | | | | | | - James G Kublin
- Department of Global Health, University of Washington, Seattle, Washington.,Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
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12
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Walk J, van Gemert GJ, Graumans W, Sauerwein RW, Bijker EM. Mosquito Infectivity and Parasitemia after Controlled Human Malaria Infection. Am J Trop Med Hyg 2018; 98:1705-1708. [PMID: 29714158 DOI: 10.4269/ajtmh.17-0952] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Controlled Human Malaria Infection (CHMI) has become an increasingly important tool for the evaluation of drugs and vaccines. Controlled Human Malaria Infection has been demonstrated to be a reproducible model; however, there is some variability in time to onset of parasitemia between volunteers and studies. At our center, mosquitoes infected with Plasmodium falciparum by membrane feeding have variable and high salivary gland sporozoite load (mean 78,415; range 26,500-160,500). To determine whether this load influences parasitemia after CHMI, we analyzed data from 13 studies. We found no correlation between the sporozoite load of a mosquito batch and time to parasitemia or parasite density of first-wave parasitemia. These findings support the use of infected mosquito bite as a reproducible means of inducing P. falciparum infection and suggest that within this range, salivary gland sporozoite load does not influence the stringency of a CHMI.
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Affiliation(s)
- Jona Walk
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Geert-Jan van Gemert
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wouter Graumans
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Robert W Sauerwein
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Else M Bijker
- Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
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13
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Kublin JG, Mikolajczak SA, Sack BK, Fishbaugher ME, Seilie A, Shelton L, VonGoedert T, Firat M, Magee S, Fritzen E, Betz W, Kain HS, Dankwa DA, Steel RWJ, Vaughan AM, Noah Sather D, Murphy SC, Kappe SHI. Complete attenuation of genetically engineered Plasmodium falciparum sporozoites in human subjects. Sci Transl Med 2018; 9:9/371/eaad9099. [PMID: 28053159 DOI: 10.1126/scitranslmed.aad9099] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 11/21/2016] [Indexed: 12/27/2022]
Abstract
Immunization of humans with whole sporozoites confers complete, sterilizing immunity against malaria infection. However, achieving consistent safety while maintaining immunogenicity of whole parasite vaccines remains a formidable challenge. We generated a genetically attenuated Plasmodium falciparum (Pf) malaria parasite by deleting three genes expressed in the pre-erythrocytic stage (Pf p52-/p36-/sap1-). We then tested the safety and immunogenicity of the genetically engineered (Pf GAP3KO) sporozoites in human volunteers. Pf GAP3KO sporozoites were delivered to 10 volunteers using infected mosquito bites with a single exposure consisting of 150 to 200 bites per subject. All subjects remained blood stage-negative and developed inhibitory antibodies to sporozoites. GAP3KO rodent malaria parasites engendered complete, protracted immunity against infectious sporozoite challenge in mice. The results warrant further clinical testing of Pf GAP3KO and its potential development into a vaccine strain.
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Affiliation(s)
- James G Kublin
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA. .,Department of Global Health, University of Washington, Seattle, WA 98195, USA.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - Sebastian A Mikolajczak
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Brandon K Sack
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Matt E Fishbaugher
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Annette Seilie
- Department of Laboratory Medicine, University of Washington, 1959 Northeast Pacific Street, NW150, Seattle, WA 98195-7110, USA
| | - Lisa Shelton
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Tracie VonGoedert
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Melike Firat
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Sara Magee
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Emma Fritzen
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Will Betz
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Heather S Kain
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Dorender A Dankwa
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Ryan W J Steel
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Ashley M Vaughan
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - D Noah Sather
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Sean C Murphy
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA.,Department of Laboratory Medicine, University of Washington, 1959 Northeast Pacific Street, NW150, Seattle, WA 98195-7110, USA.,Center for Emerging and Re-emerging Infectious Diseases and Department of Microbiology, University of Washington, 750 Republican Street, E630, Seattle, WA 98109, USA
| | - Stefan H I Kappe
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA. .,Department of Global Health, University of Washington, Seattle, WA 98195, USA
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14
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Abstract
Basic science holds enormous power for revealing the biological mechanisms of disease and, in turn, paving the way toward new, effective interventions. Recognizing this power, the 2011 Research Agenda for Malaria Eradication included key priorities in fundamental research that, if attained, could help accelerate progress toward disease elimination and eradication. The Malaria Eradication Research Agenda (malERA) Consultative Panel on Basic Science and Enabling Technologies reviewed the progress, continuing challenges, and major opportunities for future research. The recommendations come from a literature of published and unpublished materials and the deliberations of the malERA Refresh Consultative Panel. These areas span multiple aspects of the Plasmodium life cycle in both the human host and the Anopheles vector and include critical, unanswered questions about parasite transmission, human infection in the liver, asexual-stage biology, and malaria persistence. We believe an integrated approach encompassing human immunology, parasitology, and entomology, and harnessing new and emerging biomedical technologies offers the best path toward addressing these questions and, ultimately, lowering the worldwide burden of malaria.
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15
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Burrows JN, Duparc S, Gutteridge WE, Hooft van Huijsduijnen R, Kaszubska W, Macintyre F, Mazzuri S, Möhrle JJ, Wells TNC. New developments in anti-malarial target candidate and product profiles. Malar J 2017; 16:26. [PMID: 28086874 PMCID: PMC5237200 DOI: 10.1186/s12936-016-1675-x] [Citation(s) in RCA: 313] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/30/2016] [Indexed: 11/10/2022] Open
Abstract
A decade of discovery and development of new anti-malarial medicines has led to a renewed focus on malaria elimination and eradication. Changes in the way new anti-malarial drugs are discovered and developed have led to a dramatic increase in the number and diversity of new molecules presently in pre-clinical and early clinical development. The twin challenges faced can be summarized by multi-drug resistant malaria from the Greater Mekong Sub-region, and the need to provide simplified medicines. This review lists changes in anti-malarial target candidate and target product profiles over the last 4 years. As well as new medicines to treat disease and prevent transmission, there has been increased focus on the longer term goal of finding new medicines for chemoprotection, potentially with long-acting molecules, or parenteral formulations. Other gaps in the malaria armamentarium, such as drugs to treat severe malaria and endectocides (that kill mosquitoes which feed on people who have taken the drug), are defined here. Ultimately the elimination of malaria requires medicines that are safe and well-tolerated to be used in vulnerable populations: in pregnancy, especially the first trimester, and in those suffering from malnutrition or co-infection with other pathogens. These updates reflect the maturing of an understanding of the key challenges in producing the next generation of medicines to control, eliminate and ultimately eradicate malaria.
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Affiliation(s)
- Jeremy N Burrows
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | - Stephan Duparc
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | | | | | - Wiweka Kaszubska
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | - Fiona Macintyre
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | | | - Jörg J Möhrle
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | - Timothy N C Wells
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland.
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16
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Methodical Considerations. HUMAN VACCINES 2017. [DOI: 10.1016/b978-0-12-802302-0.00006-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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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] [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.
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18
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Walk J, Schats R, Langenberg MCC, Reuling IJ, Teelen K, Roestenberg M, Hermsen CC, Visser LG, Sauerwein RW. Diagnosis and treatment based on quantitative PCR after controlled human malaria infection. Malar J 2016; 15:398. [PMID: 27495296 PMCID: PMC4974752 DOI: 10.1186/s12936-016-1434-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 07/08/2016] [Indexed: 11/29/2022] Open
Abstract
Background Controlled human malaria infection (CHMI) has become well-established in the evaluation of drugs and vaccines. Anti-malarial treatment is usually initiated when thick blood smears are positive by microscopy. This study explores the effects of using the more sensitive qPCR as the primary diagnostic test. Methods 1691 diagnostic blood samples were analysed by microscopy and qPCR from 115 volunteers (55 malaria naïve and 60 having received chemoprophylaxis and sporozoite immunization) who were challenged by five mosquitoes infected with Plasmodium falciparum sporozoites of the NF54 strain. Results Retrospective analysis of different qPCR criteria for diagnosis and treatment, showed that once daily qPCR (threshold 100 parasites/ml) had 99 % sensitivity and 100 % specificity, and shortened the median prepatent period from 10.5 to 7.0 days after CHMI when compared to twice daily measurement of thick blood smears (threshold 4000 parasites/ml). This is expected to result in a 78 % decrease of adverse events before initiation of treatment in future studies. Trial outcome related to infection and protective efficacy remained unchanged. Conclusion The use of qPCR as the primary diagnostic test in CHMI decreases symptoms as well as parasitaemia while obviating the need for twice daily follow-up. The implementation improves safety while reducing the clinical burden and costs without compromising the evaluation of protective efficacy.
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Affiliation(s)
- Jona Walk
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Remko Schats
- Department of Infectious Diseases, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
| | - Marijke C C Langenberg
- Department of Infectious Diseases, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
| | - Isaie J Reuling
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Karina Teelen
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Meta Roestenberg
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Cornelus C Hermsen
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Leo G Visser
- Department of Infectious Diseases, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud university medical center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
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19
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A review of reverse vaccinology approaches for the development of vaccines against ticks and tick borne diseases. Ticks Tick Borne Dis 2015; 7:573-85. [PMID: 26723274 DOI: 10.1016/j.ttbdis.2015.12.012] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/24/2015] [Accepted: 12/12/2015] [Indexed: 02/07/2023]
Abstract
The field of reverse vaccinology developed as an outcome of the genome sequence revolution. Following the introduction of live vaccinations in the western world by Edward Jenner in 1798 and the coining of the phrase 'vaccine', in 1881 Pasteur developed a rational design for vaccines. Pasteur proposed that in order to make a vaccine that one should 'isolate, inactivate and inject the microorganism' and these basic rules of vaccinology were largely followed for the next 100 years leading to the elimination of several highly infectious diseases. However, new technologies were needed to conquer many pathogens which could not be eliminated using these traditional technologies. Thus increasingly, computers were used to mine genome sequences to rationally design recombinant vaccines. Several vaccines for bacterial and viral diseases (i.e. meningococcus and HIV) have been developed, however the on-going challenge for parasite vaccines has been due to their comparatively larger genomes. Understanding the immune response is important in reverse vaccinology studies as this knowledge will influence how the genome mining is to be conducted. Vaccine candidates for anaplasmosis, cowdriosis, theileriosis, leishmaniasis, malaria, schistosomiasis, and the cattle tick have been identified using reverse vaccinology approaches. Some challenges for parasite vaccine development include the ability to address antigenic variability as well the understanding of the complex interplay between antibody, mucosal and/or T cell immune responses. To understand the complex parasite interactions with the livestock host, there is the limitation where algorithms for epitope mining using the human genome cannot directly be adapted for bovine, for example the prediction of peptide binding to major histocompatibility complex motifs. As the number of genomes for both hosts and parasites increase, the development of new algorithms for pan-genomic mining will continue to impact the future of parasite and ricketsial (and other tick borne pathogens) disease vaccine development.
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Moreno A, Joyner C. Malaria vaccine clinical trials: what's on the horizon. Curr Opin Immunol 2015; 35:98-106. [PMID: 26172291 DOI: 10.1016/j.coi.2015.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 06/12/2015] [Accepted: 06/22/2015] [Indexed: 01/01/2023]
Abstract
Significant progress toward a malaria vaccine, specifically for Plasmodium falciparum, has been made in the past few years with the completion of numerous clinical trials. Each trial has utilized a unique combination of antigens, delivery platforms, and adjuvants, which has provided the research community with a wealth of critical information to apply towards the development of next generation malaria vaccines. Despite the progress toward a P. falciparum vaccine, P. vivax vaccine research requires more momentum and additional investigations to identify novel vaccine candidates. In this review, recently completed and ongoing malaria vaccine clinical trials as well as vaccine candidates that are in the development pipeline are reviewed. Perspectives for future research using post-genomic mining, nonhuman primate models, and systems biology are also discussed.
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Affiliation(s)
- Alberto Moreno
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, 954 Gatewood Road, Atlanta, GA 30329, USA; Malaria Host-Pathogen Interaction Center, Emory University, 954 Gatewood Road, Atlanta, GA 30329, USA; Division of Infectious Diseases, Department of Medicine, Emory University, 69 Jesse Hill, Jr. Drive, SE, Atlanta, GA 30303, USA.
| | - Chester Joyner
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, 954 Gatewood Road, Atlanta, GA 30329, USA; Malaria Host-Pathogen Interaction Center, Emory University, 954 Gatewood Road, Atlanta, GA 30329, USA
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