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Al-Osaimi HM, Kanan M, Marghlani L, Al-Rowaili B, Albalawi R, Saad A, Alasmari S, Althobaiti K, Alhulaili Z, Alanzi A, Alqarni R, Alsofiyani R, Shrwani R. A systematic review on malaria and dengue vaccines for the effective management of these mosquito borne diseases: Improving public health. Hum Vaccin Immunother 2024; 20:2337985. [PMID: 38602074 PMCID: PMC11017952 DOI: 10.1080/21645515.2024.2337985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
Insect vector-borne diseases (VBDs) pose significant global health challenges, particularly in tropical and subtropical regions. The WHO has launched the "Global Vector Control Response (GVCR) 2017-2030" to address these diseases, emphasizing a comprehensive approach to vector control. This systematic review investigates the potential of malaria and dengue vaccines in controlling mosquito-borne VBDs, aiming to alleviate disease burdens and enhance public health. Following PRISMA 2020 guidelines, the review incorporated 39 new studies out of 934 identified records. It encompasses various studies assessing malaria and dengue vaccines, emphasizing the significance of vaccination as a preventive measure. The findings indicate variations in vaccine efficacy, duration of protection, and safety considerations for each disease, influencing public health strategies. The review underscores the urgent need for vaccines to combat the increasing burden of VBDs like malaria and dengue, advocating for ongoing research and investment in vaccine development.
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Affiliation(s)
- Hind M. Al-Osaimi
- Department of Pharmacy Services Administration, King Fahad Medical City, Riyadh Second Health Cluster, Riyadh, Kingdom of Saudi Arabia
| | - Mohammed Kanan
- Department of Clinical Pharmacy, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia
| | - Lujain Marghlani
- Department of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
| | - Badria Al-Rowaili
- Pharmaceutical Services Department, Northern Area Armed Forces Hospital, King Khalid Military, Hafr Al Batin, Kingdom of Saudi Arabia
| | - Reem Albalawi
- Department of Medicine, Tabuk University, Tabuk, Kingdom of Saudi Arabia
| | - Abrar Saad
- Pharmacy Department, Royal Commission Hospital, Yanbu, Kingdom of Saudi Arabia
| | - Saba Alasmari
- Department of Clinical Pharmacy, King Khalid University, Jeddah, Kingdom of Saudi Arabia
| | - Khaled Althobaiti
- Department of Medicine, Taif University, Ta’if, Kingdom of Saudi Arabia
| | - Zainab Alhulaili
- Department of Clinical Pharmacy, Dammam Medical Complex, Dammam, Kingdom of Saudi Arabia
| | - Abeer Alanzi
- Department of Medicine, King Abdulaziz Hospital, Makkah, Kingdom of Saudi Arabia
| | - Rawan Alqarni
- Department of Medicine and Surgery, King Khalid University, Abha, Kingdom of Saudi Arabia
| | - Razan Alsofiyani
- Department of Medicine, Taif University, Ta’if, Kingdom of Saudi Arabia
| | - Reem Shrwani
- Department of Clinical Pharmacy, Jazan University, Jazan, Kingdom of Saudi Arabia
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Kusi KA, Amoah LE, Acquah FK, Ennuson NA, Frempong AF, Ofori EA, Akyea-Mensah K, Kyei-Baafour E, Osei F, Frimpong A, Singh SK, Theisen M, Remarque EJ, Faber BW, Belmonte M, Ganeshan H, Huang J, Villasante E, Sedegah M. Plasmodium falciparum AMA1 and CSP antigen diversity in parasite isolates from southern Ghana. Front Cell Infect Microbiol 2024; 14:1375249. [PMID: 38808064 PMCID: PMC11132687 DOI: 10.3389/fcimb.2024.1375249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/19/2024] [Indexed: 05/30/2024] Open
Abstract
Introduction Diversity in malarial antigens is an immune evasion mechanism that gives malaria parasites an edge over the host. Immune responses against one variant of a polymorphic antigen are usually not fully effective against other variants due to altered epitopes. This study aimed to evaluate diversity in the Plasmodium falciparum antigens apical membrane antigen 1 (PfAMA1) and circumsporozoite protein (PfCSP) from circulating parasites in a malaria-endemic community in southern Ghana and to determine the effects of polymorphisms on antibody response specificity. Methods The study involved 300 subjects, whose P. falciparum infection status was determined by microscopy and PCR. Diversity within the two antigens was evaluated by msp2 gene typing and molecular gene sequencing, while the host plasma levels of antibodies against PfAMA1, PfCSP, and two synthetic 24mer peptides from the conserved central repeat region of PfCSP, were measured by ELISA. Results Of the 300 subjects, 171 (57%) had P. falciparum infection, with 165 of the 171 (96.5%) being positive for either or both of the msp2 allelic families. Gene sequencing of DNA from 55 clonally infected samples identified a total of 56 non-synonymous single nucleotide polymorphisms (SNPs) for the Pfama1 gene and these resulted in 44 polymorphic positions, including two novel positions (363 and 365). Sequencing of the Pfcsp gene from 69 clonal DNA samples identified 50 non-synonymous SNPs that resulted in 42 polymorphic positions, with half (21) of these polymorphic positions being novel. Of the measured antibodies, only anti-PfCSP antibodies varied considerably between PCR parasite-positive and parasite-negative persons. Discussion These data confirm the presence of a considerable amount of unique, previously unreported amino acid changes, especially within PfCSP. Drivers for this diversity in the Pfcsp gene do not immediately seem apparent, as immune pressure will be expected to drive a similar level of diversity in the Pfama1 gene.
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Affiliation(s)
- Kwadwo A. Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Linda E. Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Festus Kojo Acquah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Nana Aba Ennuson
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Abena F. Frempong
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Ebenezer A. Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Kwadwo Akyea-Mensah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Eric Kyei-Baafour
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Frank Osei
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Augustina Frimpong
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Susheel K. Singh
- Center for Medical Parasitology at the Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Congenital Diseases, Statens Serum Institut, Copenhagen, Denmark
| | - Michael Theisen
- Center for Medical Parasitology at the Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Congenital Diseases, Statens Serum Institut, Copenhagen, Denmark
| | - Edmond J. Remarque
- Department of Parasitology, Biomedical Primate Research Center, Rijswijk, Netherlands
| | - Bart W. Faber
- Department of Parasitology, Biomedical Primate Research Center, Rijswijk, Netherlands
| | - Maria Belmonte
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Harini Ganeshan
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Jun Huang
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Eileen Villasante
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Martha Sedegah
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
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3
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Lyimo BM, Bakari C, Popkin-Hall ZR, Giesbrecht DJ, Seth MD, Pereus D, Shabani ZI, Moshi R, Boniface R, Mandara CI, Madebe R, Juliano JJ, Bailey JA, Ishengoma DS. Genetic polymorphism and evidence of signatures of selection in the Plasmodium falciparum circumsporozoite protein gene in Tanzanian regions with different malaria endemicity. Malar J 2024; 23:139. [PMID: 38720288 PMCID: PMC11080125 DOI: 10.1186/s12936-024-04974-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND In 2021 and 2023, the World Health Organization approved RTS,S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (PfCSP), but polymorphisms in the gene raise concerns regarding strain-specific responses and the long-term efficacy of these vaccines. This study assessed the Pfcsp genetic diversity, population structure and signatures of selection among parasites from areas of different malaria transmission intensities in Mainland Tanzania, to generate baseline data before the introduction of the malaria vaccines in the country. METHODS The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of Mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (Fws), Wright's fixation index (FST), principal component analysis, nucleotide diversity, and Tajima's D were used to assess within-host parasite diversity, population structure and natural selection. RESULTS Based on Fws (< 0.95), there was high polyclonality (ranging from 69.23% in Nachingwea to 56.9% in Muheza). No population structure was detected in the Pfcsp gene in the five regions (mean FST = 0.0068). The average nucleotide diversity (π), nucleotide differentiation (K) and haplotype diversity (Hd) in the five regions were 4.19, 0.973 and 0.0035, respectively. The C-terminal region of Pfcsp showed high nucleotide diversity at Th2R and Th3R regions. Positive values for the Tajima's D were observed in the Th2R and Th3R regions consistent with balancing selection. The Pfcsp C-terminal sequences revealed 50 different haplotypes (H_1 to H_50), with only 2% of sequences matching the 3D7 strain haplotype (H_50). Conversely, with the NF54 strain, the Pfcsp C-terminal sequences revealed 49 different haplotypes (H_1 to H_49), with only 0.4% of the sequences matching the NF54 strain (Hap_49). CONCLUSIONS The findings demonstrate high diversity of the Pfcsp gene with limited population differentiation. The Pfcsp gene showed positive Tajima's D values, consistent with balancing selection for variants within Th2R and Th3R regions. The study observed differences between the intended haplotypes incorporated into the design of RTS,S and R21 vaccines and those present in natural parasite populations. Therefore, additional research is warranted, incorporating other regions and more recent data to comprehensively assess trends in genetic diversity within this important gene. Such insights will inform the choice of alleles to be included in the future vaccines.
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Affiliation(s)
- Beatus M Lyimo
- National Institute for Medical Research, Dar es Salaam, Tanzania.
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.
| | - Catherine Bakari
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Misago D Seth
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Dativa Pereus
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Zulfa I Shabani
- Dar Es Salaam University College of Education, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Ramadhan Moshi
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Ruth Boniface
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Celine I Mandara
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Rashid Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Harvard T.H Chan School of Public Health, Boston, MA, USA
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia
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4
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Lyimo BM, Bakari C, Popkin-Hall ZR, Giesbrecht DJ, Seth MD, Pereus D, Moshi R, Boniface R, Mandara CI, Madebe R, Juliano JJ, Bailey JA, Ishengoma DS. Genetic polymorphism and evidence of signatures of selection in the Plasmodium falciparum circumsporozoite protein gene in Tanzanian regions with different malaria endemicity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.23.24301587. [PMID: 38343796 PMCID: PMC10854334 DOI: 10.1101/2024.01.23.24301587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Background In 2021 and 2023, the World Health Organization approved RTS, S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (Pfcsp) but polymorphisms in this gene raises concerns regarding strain-specific responses and the long-term efficacy of these vaccines. This study assessed the Pfcsp genetic diversity, population structure and signatures of selection among parasites from areas of different malaria transmission in mainland Tanzania, to generate baseline data before the introduction of the malaria vaccines in the country. Methods The analysis involved 589 whole genome sequences generated by and as part of the MalariaGEN Community Project. The samples were collected between 2013 and January 2015 from five regions of mainland Tanzania: Morogoro and Tanga (Muheza) (moderate transmission areas), and Kagera (Muleba), Lindi (Nachingwea), and Kigoma (Ujiji) (high transmission areas). Wright's inbreeding coefficient (Fws), Wright's fixation index (FST), principal component analysis, nucleotide diversity, and Tajima's D were used to assess within-host parasite diversity, population structure and natural selection. Results Based on Fws (< 0.95), there was high polyclonality (ranged from 69.23% in Nachingwea to 56.9% in Muheza). No population structure was detected in the Pfcsp gene in the five regions (mean FST= 0.0068). The average nucleotide diversity (π), nucleotide differentiation (K) and haplotype diversity (Hd) in the five regions were 4.19, 0.973 and 0.0035, respectively. The C-terminal region of Pfcsp showed high nucleotide diversity at Th2R and Th3R regions. Positive values for the Tajima's D were observed in the Th2R and Th3R regions consistent with balancing selection. The Pfcsp C-terminal sequences had 50 different haplotypes (H_1 to H_50) and only 2% of sequences matched the 3D7 strain haplotype (H_50). Conclusions The findings demonstrate high diversity of the Pfcsp gene with limited population differentiation. The Pfcsp gene showed positive Tajima's D values for parasite populations, consistent with balancing selection for variants within Th2R and Th3R regions. This data is consistent with other studies conducted across Africa and worldwide, which demonstrate low 3D7 haplotypes and little population structure. Therefore, additional research is warranted, incorporating other regions and more recent data to comprehensively assess trends in genetic diversity within this important gene. Such insights will inform the choice of alleles to be included in the future vaccines.
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Affiliation(s)
- Beatus M. Lyimo
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Catherine Bakari
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Misago D. Seth
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Dativa Pereus
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Ramadhan Moshi
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Ruth Boniface
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | | | - Rashid Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | | | - Deus S. Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania
- Harvard T.H Chan School of Public Health, Boston, MA, USA
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia
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Abo YN, Jamrozik E, McCarthy JS, Roestenberg M, Steer AC, Osowicki J. Strategic and scientific contributions of human challenge trials for vaccine development: facts versus fantasy. THE LANCET. INFECTIOUS DISEASES 2023; 23:e533-e546. [PMID: 37573871 DOI: 10.1016/s1473-3099(23)00294-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 08/15/2023]
Abstract
The unprecedented speed of delivery of SARS-CoV-2 pandemic vaccines has redefined the limits for all vaccine development. Beyond the aspirational 100-day timeline for tomorrow's hypothetical pandemic vaccines, there is a sense of optimism that development of other high priority vaccines can be accelerated. Early in the COVID-19 pandemic, an intense and polarised academic and public discourse arose concerning the role of human challenge trials for vaccine development. A case was made for human challenge trials as a powerful tool to establish early proof-of-concept of vaccine efficacy in humans, inform vaccine down selection, and address crucial knowledge gaps regarding transmission, pathogenesis, and immune protection. We review the track record of human challenge trials contributing to the development of vaccines for 19 different pathogens and discuss relevant limitations, barriers, and pitfalls. This Review also highlights opportunities for efforts to broaden the scope and boost the effects of human challenge trials, to accelerate all vaccine development.
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Affiliation(s)
- Yara-Natalie Abo
- Tropical Diseases Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, VIC, Australia.
| | - Euzebiusz Jamrozik
- Ethox and Pandemic Sciences Institute, Nuffield Department of Population Health, University of Oxford, Oxford, UK; Monash-WHO Collaborating Centre for Bioethics, Monash University, Melbourne, VIC, Australia
| | - James S McCarthy
- Department of Infectious Diseases, The University of Melbourne, Parkville, VIC, Australia; Victorian Infectious Diseases Services, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Meta Roestenberg
- Controlled Human Infections Center, Leiden University Medical Center, Leiden, Netherlands
| | - Andrew C Steer
- Tropical Diseases Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, VIC, Australia
| | - Joshua Osowicki
- Tropical Diseases Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, VIC, Australia
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6
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Abstract
Malaria is a mosquito-borne disease caused by protozoan parasites of the genus Plasmodium. Despite significant declines in malaria-attributable morbidity and mortality over the last two decades, it remains a major public health burden in many countries. This underscores the critical need for improved strategies to prevent, treat and control malaria if we are to ultimately progress towards the eradication of this disease. Ideally, this will include the development and deployment of a highly effective malaria vaccine that is able to induce long-lasting protective immunity. There are many malaria vaccine candidates in development, with more than a dozen of these in clinical development. RTS,S/AS01 (also known as Mosquirix) is the most advanced malaria vaccine and was shown to have modest efficacy against clinical malaria in phase III trials in 5- to 17-month-old infants. Following pilot implementation trials, the World Health Organisation has recommended it for use in Africa in young children who are most at risk of infection with P. falciparum, the deadliest of the human malaria parasites. It is well recognised that more effective malaria vaccines are needed. In this review, we discuss malaria vaccine candidates that have progressed into clinical evaluation and highlight the most advanced candidates: Sanaria's irradiated sporozoite vaccine (PfSPZ Vaccine), the chemoattenuated sporozoite vaccine (PfSPZ-CVac), RTS,S/AS01 and the novel malaria vaccine candidate, R21, which displayed promising, high-level efficacy in a recent small phase IIb trial in Africa.
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Affiliation(s)
- Danielle I Stanisic
- 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.
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Oludada OE, Costa G, Burn Aschner C, Obraztsova AS, Prieto K, Canetta C, Hoffman SL, Kremsner PG, Mordmüller B, Murugan R, Julien JP, Levashina EA, Wardemann H. Molecular and functional properties of human Plasmodium falciparum CSP C-terminus antibodies. EMBO Mol Med 2023:e17454. [PMID: 37082831 DOI: 10.15252/emmm.202317454] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/11/2023] [Accepted: 03/23/2023] [Indexed: 04/22/2023] Open
Abstract
Human monoclonal antibodies (mAbs) against the central repeat and junction domain of Plasmodium falciparum circumsporozoite protein (PfCSP) have been studied extensively to guide malaria vaccine design compared to antibodies against the PfCSP C terminus. Here, we describe the molecular characteristics and protective potential of 73 germline and mutated human mAbs against the highly immunogenic PfCSP C-terminal domain. Two mAbs recognized linear epitopes in the C-terminal linker with sequence similarity to repeat and junction motifs, whereas all others targeted conformational epitopes in the α-thrombospondin repeat (α-TSR) domain. Specificity for the polymorphic Th2R/Th3R but not the conserved RII+/CS.T3 region in the α-TSR was associated with IGHV3-21/IGVL3-21 or IGLV3-1 gene usage. Although the C terminus specific mAbs showed signs of more efficient affinity maturation and class-switching compared to anti-repeat mAbs, live sporozoite binding and inhibitory activity was limited to a single C-linker reactive mAb with cross-reactivity to the central repeat and junction. The data provide novel insights in the human anti-C-linker and anti-α-TSR antibody response that support exclusion of the PfCSP C terminus from malaria vaccine designs.
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Affiliation(s)
- Opeyemi Ernest Oludada
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
- Biosciences Faculty, University of Heidelberg, Germany
| | - Giulia Costa
- Vector Biology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | | | - Anna S Obraztsova
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
- Biosciences Faculty, University of Heidelberg, Germany
| | - Katherine Prieto
- The Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | - Caterina Canetta
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
| | | | - Peter G Kremsner
- Institute of Tropical Medicine, Tübingen, Germany
- Centre de Recherches de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, Tübingen, Germany
- Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rajagopal Murugan
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Jean-Philippe Julien
- The Hospital for Sick Children Research Institute, Toronto, ON, Canada
- Departments of Biochemistry and Immunology, University of Toronto, Toronto, ON, Canada
| | - Elena A Levashina
- Vector Biology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Hedda Wardemann
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
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Yihunie W, Kebede B, Tegegne BA, Getachew M, Abebe D, Aschale Y, Belew H, Bahiru B. Systematic Review of Safety of RTS,S with AS01 and AS02 Adjuvant Systems Using Data from Randomized Controlled Trials in Infants, Children, and Adults. Clin Pharmacol 2023; 15:21-32. [PMID: 36941908 PMCID: PMC10024506 DOI: 10.2147/cpaa.s400155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/07/2023] [Indexed: 03/16/2023] Open
Abstract
Background Emergence of antimalarial drugs and insecticides resistance alarms scientists to develop a safe and effective malaria vaccine. A pre-erythrocytic malaria vaccine called RTS,S has made great strides. Aim The review was aimed to assess the safety of the candidate malaria vaccine RTS,S with AS01 and AS02 adjuvants using data from Phase I-III randomized controlled clinical trials (RCTs). Methods This systematic review was conducted based on PRISMA 2020. Regardless of time of publication year, all articles related with safety of RTS,S, RCTs published in the English language were included in the study. The last search of databases, and registry was conducted on 30 May, 2022. Pubmed, Google Scholar, Cochrane Library, Wiley Online Library, and Clinical trials.gov were thoroughly searched for accessible RCTs on the safety of RTS,S malaria vaccine. The studies were screened in three steps: duplicate removal, title and abstract screening, and full-text review. The included studies' bias risk was assessed using the Cochrane risk of bias tool for RCTs. This systematic review is registered at Prospero (registration number: CRD42021285888). The qualitative descriptive findings from the included published studies were reported stratified by clinical trial phases. Findings A total of thirty-five eligible safety studies were identified. Injection site pain and swelling, febrile convulsion, fever, headache, meningitis, fatigue, gastroenteritis, myalgia, pneumonia, reactogenicity, and anemia were the most commonly reported adverse events. Despite few clinical trials reported serious adverse events, none of them were related to vaccination. Conclusion Most of the adverse events observed from RTS,S/AS01 and RTS,S/AS02 malaria vaccines were reported in the control group and shared by other vaccines. Hence, the authors concluded that both RTS,S/AS01 and RTS,S/AS02 malaria vaccines are safe.
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Affiliation(s)
- Wubetu Yihunie
- Department of Pharmacy, College of Health Sciences, Debre Markos University, Debre Markos, Ethiopia
| | - Bekalu Kebede
- Department of Pharmacy, College of Health Sciences, Debre Markos University, Debre Markos, Ethiopia
| | - Bantayehu Addis Tegegne
- Department of Pharmacy, College of Health Sciences, Debre Markos University, Debre Markos, Ethiopia
| | - Melese Getachew
- Department of Pharmacy, College of Health Sciences, Debre Markos University, Debre Markos, Ethiopia
| | - Dehnnet Abebe
- Department of Pharmacy, College of Health Sciences, Debre Markos University, Debre Markos, Ethiopia
| | - Yibeltal Aschale
- Department of Medical Laboratory Science, College of Health Sciences, Debre Markos University, Debre Markos, Ethiopia
| | - Habtamu Belew
- Department of Medical Laboratory Science, College of Health Sciences, Debre Markos University, Debre Markos, Ethiopia
| | - Bereket Bahiru
- Department of Pharmacy, College of Medicine and health sciences, Bahir Dar University, Bahir Dar, Ethiopia
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Nielsen CM, Barrett JR, Davis C, Fallon JK, Goh C, Michell AR, Griffin C, Kwok A, Loos C, Darko S, Laboune F, Tekman M, Diouf A, Miura K, Francica JR, Ransier A, Long CA, Silk SE, Payne RO, Minassian AM, Lauffenburger DA, Seder RA, Douek DC, Alter G, Draper SJ. Delayed boosting improves human antigen-specific Ig and B cell responses to the RH5.1/AS01B malaria vaccine. JCI Insight 2023; 8:163859. [PMID: 36692019 PMCID: PMC9977309 DOI: 10.1172/jci.insight.163859] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/30/2022] [Indexed: 01/24/2023] Open
Abstract
Modifications to vaccine delivery that increase serum antibody longevity are of great interest for maximizing efficacy. We have previously shown that a delayed fractional (DFx) dosing schedule (0-1-6 month) - using AS01B-adjuvanted RH5.1 malaria antigen - substantially improves serum IgG durability as compared with monthly dosing (0-1-2 month; NCT02927145). However, the underlying mechanism and whether there are wider immunological changes with DFx dosing were unclear. Here, PfRH5-specific Ig and B cell responses were analyzed in depth through standardized ELISAs, flow cytometry, systems serology, and single-cell RNA-Seq (scRNA-Seq). Data indicate that DFx dosing increases the magnitude and durability of circulating PfRH5-specific B cells and serum IgG1. At the peak antibody magnitude, DFx dosing was distinguished by a systems serology feature set comprising increased FcRn binding, IgG avidity, and proportion of G2B and G2S2F IgG Fc glycans, alongside decreased IgG3, antibody-dependent complement deposition, and proportion of G1S1F IgG Fc glycan. Concomitantly, scRNA-Seq data show a higher CDR3 percentage of mutation from germline and decreased plasma cell gene expression in circulating PfRH5-specific B cells. Our data, therefore, reveal a profound impact of DFx dosing on the humoral response and suggest plausible mechanisms that could enhance antibody longevity, including improved FcRn binding by serum Ig and a potential shift in the underlying cellular response from circulating short-lived plasma cells to nonperipheral long-lived plasma cells.
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Affiliation(s)
| | | | - Christine Davis
- Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA
| | - Jonathan K. Fallon
- Ragon Institute of Massachusetts General Hospital (MGH), MIT and Harvard, Boston, Massachusetts, USA
| | - Cyndi Goh
- University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Ashlin R. Michell
- Ragon Institute of Massachusetts General Hospital (MGH), MIT and Harvard, Boston, Massachusetts, USA
| | - Catherine Griffin
- Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA
| | - Andrew Kwok
- University of Oxford, Oxford, Oxfordshire, United Kingdom.,Wellcome Center for Human Genetics, University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Carolin Loos
- Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA.,Ragon Institute of Massachusetts General Hospital (MGH), MIT and Harvard, Boston, Massachusetts, USA
| | - Samuel Darko
- Vaccine Research Center, NIAID/NIH, Bethesda, Maryland, USA
| | - Farida Laboune
- Vaccine Research Center, NIAID/NIH, Bethesda, Maryland, USA
| | - Mehmet Tekman
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | | | - Amy Ransier
- Vaccine Research Center, NIAID/NIH, Bethesda, Maryland, USA
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | - Sarah E. Silk
- University of Oxford, Oxford, Oxfordshire, United Kingdom
| | - Ruth O. Payne
- University of Oxford, Oxford, Oxfordshire, United Kingdom
| | | | | | | | | | - Galit Alter
- Ragon Institute of Massachusetts General Hospital (MGH), MIT and Harvard, Boston, Massachusetts, USA
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10
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Beeson JG, Kurtovic L, Valim C, Asante KP, Boyle MJ, Mathanga D, Dobano C, Moncunill G. The RTS,S malaria vaccine: Current impact and foundation for the future. Sci Transl Med 2022; 14:eabo6646. [DOI: 10.1126/scitranslmed.abo6646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The RTS,S vaccine has recently been recommended for implementation as a childhood vaccine in regions with moderate-to-high malaria transmission. We discuss mechanisms of vaccine protection and longevity, implementation considerations, and future research needed to increase the vaccine’s health impact, including vaccine modifications for higher efficacy and longevity of protection.
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Affiliation(s)
- James G. Beeson
- Burnet Institute, Melbourne 3004, Victoria, Australia
- Department of Infectious Diseases, University of Melbourne, Victoria, Australia
- Monash University, Central Clinical School and Department of Microbiology, Victoria, Australia
| | - Liriye Kurtovic
- Burnet Institute, Melbourne 3004, Victoria, Australia
- Monash University, Central Clinical School and Department of Microbiology, Victoria, Australia
| | - Clarissa Valim
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
| | - Kwaku Poku Asante
- Kintampo Health Research Centre, Kintampo North Municipality, Bono East Region, Ghana
| | - Michelle J. Boyle
- QIMR Berghofer Institute, Herston, Queensland, Australia
- University of Queensland, School of Biomedical Sciences, St Lucia, Queensland, Australia
- Griffith University, Brisbane, Queensland, Australia
| | - Don Mathanga
- Malaria Alert Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Carlota Dobano
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia, Spain
- CIBER Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Gemma Moncunill
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia, Spain
- CIBER Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
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11
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Abstract
RTS,S/AS01 (Mosquirix®) is a vaccine against malaria caused by Plasmodium falciparum. In a phase 3 trial, RTS,S/AS01 showed vaccine efficacy against clinical malaria, severe malaria and malaria hospitalization, with an acceptable safety and tolerability profile, in children aged 6 weeks to 17 months; the vaccine efficacy was greater in children than in infants and waned over time. In another phase 3 trial, RTS,S/AS01 was noninferior to seasonal malaria chemoprevention in children. WHO recommends a 4-dose schedule of RTS,S/AS01 for the prevention of P. falciparum malaria in children from 5 months of age living in regions with moderate to high malaria transmission, with an optional 5-dose schedule for areas with highly seasonal malaria transmission. First results from large pilot implementation in Africa show that RTS,S/AS01 has a favourable safety profile, increases equity in access to malaria prevention, is highly cost effective, can be delivered through routine national immunization programmes and substantially reduces severe malaria burden. Malaria is a life-threatening disease caused by Plasmodium parasites, which are spread to humans through bites of infected mosquitoes. RTS,S/AS01 (Mosquirix®) is a vaccine against malaria caused by P. falciparum. In phase 3 trials, RTS,S/AS01 showed vaccine efficacy against P. falciparum malaria and was at least as effective as seasonal malaria chemoprevention in children, with an acceptable safety and tolerability profile. Results of the first 2 years of a large scale pilot implementation of RTS,S/AS01 in Africa allowed WHO to recommend the vaccine for the prevention of P. falciparum malaria in children from 5 months of age living in regions with moderate to high malaria transmission, with an optional use for seasonal malaria.
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12
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Samuels AM, Ansong D, Kariuki SK, Adjei S, Bollaerts A, Ockenhouse C, Westercamp N, Lee CK, Schuerman L, Bii DK, Osei-Tutu L, Oneko M, Lievens M, Attobrah Sarfo MA, Atieno C, Morelle D, Bakari A, Sang T, Jongert E, Kotoh-Mortty MF, Otieno K, Roman F, Buabeng PBY, Ntiamoah Y, Ofori-Anyinam O, Agbenyega T, Sambian D, Agordo Dornudo A, Nana Badu L, Akoi K, Antwi E, Onoka K, K'Orimba K, Ndaya Oloo P, Leakey E, Gvozdenovic E, Cravcenco C, Vandoolaeghe P, Vekemans J, Ivinson K. Efficacy of RTS,S/AS01E malaria vaccine administered according to different full, fractional, and delayed third or early fourth dose regimens in children aged 5–17 months in Ghana and Kenya: an open-label, phase 2b, randomised controlled trial. THE LANCET INFECTIOUS DISEASES 2022; 22:1329-1342. [PMID: 35753316 PMCID: PMC9420828 DOI: 10.1016/s1473-3099(22)00273-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/17/2022] [Accepted: 04/19/2022] [Indexed: 10/25/2022]
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13
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He ZQ, Zhang QQ, Wang D, Hu YB, Zhou RM, Qian D, Yang CY, Lu DL, Li SH, Liu Y, Zhang HW. Genetic polymorphism of circumsporozoite protein of Plasmodium falciparum among Chinese migrant workers returning from Africa to Henan Province. Malar J 2022; 21:248. [PMID: 36030242 PMCID: PMC9419638 DOI: 10.1186/s12936-022-04275-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 08/18/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum malaria is recognized as a major global public health problem. The malaria vaccine was important because the case fatality rate of falciparum malaria was high. Plasmodium falciparum circumsporozoite protein (PfCSP) is one of the potential vaccine candidates, but the genetic polymorphism of PfCSP raises concerns regarding the efficacy of the vaccine. This study aimed to investigate the genetic polymorphism of PfCSP and provide data for the improvement of PfCSP-based vaccine (RTS,S malaria vaccine). METHODS Blood samples were collected from 287 Chinese migrant workers who were infected with P. falciparum and returning from Africa to Henan Province during 2016-2018. The Pfcsp genes were analysed to estimate the genetic diversity of this parasite. RESULTS The results showed that there were two mutations at the N-terminus of imported Pfcsp in Henan Province, including insertion amino acids (58.71%, 118/201) and A → G (38.81%, 78/201). The number of repeats of tetrapeptide motifs (NANP/NVDP/NPNP/NVDA) in the central repeat region ranged mainly from 39 to 42 (97.51%, 196/201). A total of 14 nonsynonymous amino acid changes were found at the C-terminus. The average nucleotide difference (K) of imported Pfcsp in Henan Province was 5.719, and the haplotype diversity (Hd) was 0.964 ± 0.004. The estimated value of dN-dS was 0.047, indicating that the region may be affected by positive natural selection. The minimum number of recombination events (Rm) of imported Pfcsp in Henan Province was close to that in Africa. The analysis of genetic differentiation showed that there may be moderate differentiation between East Africa and North Africa (Fst = 0.06484), and the levels of differentiation in the other regions were very small (Fst < 0.05). CONCLUSIONS The N-terminus of Pfcsp was relatively conserved, and the central repeat region and the Th2R and Th3R regions of the C-terminus were highly polymorphic. The gene polymorphism pattern among Chinese migrant workers returning from Africa to Henan Province was consistent with that in Africa. The geographical pattern of population differentiation and the evidence of natural selection and gene recombination suggested that the effect of polymorphism on the efficacy of PfCSP-based vaccines should be considered.
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Affiliation(s)
- Zhi-Quan He
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China.,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China
| | - Qun-Qun Zhang
- Fengtai District Center for Disease Control and Prevention, Beijing, China
| | - Dan Wang
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China.,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China
| | - Ya-Bo Hu
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Rui-Min Zhou
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China.,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China
| | - Dan Qian
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China.,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China
| | - Cheng-Yun Yang
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China.,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China
| | - De-Ling Lu
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China.,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China
| | - Su-Hua Li
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China.,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China
| | - Ying Liu
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China. .,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China.
| | - Hong-Wei Zhang
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China. .,Henan Key Laboratory of Pathogenic Microorganisms, No. 105 South Agricultural Road, Zhengdong New District, Zhengzhou, 450016, China.
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14
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Feng G, Kurtovic L, Agius PA, Aitken EH, Sacarlal J, Wines BD, Hogarth PM, Rogerson SJ, Fowkes FJI, Dobaño C, Beeson JG. Induction, decay, and determinants of functional antibodies following vaccination with the RTS,S malaria vaccine in young children. BMC Med 2022; 20:289. [PMID: 36002841 PMCID: PMC9402280 DOI: 10.1186/s12916-022-02466-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 07/06/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND RTS,S is the first malaria vaccine recommended for implementation among young children at risk. However, vaccine efficacy is modest and short-lived. Antibodies play the major role in vaccine-induced immunity, but knowledge on the induction, decay, and determinants of antibody function is limited, especially among children. Antibodies that promote opsonic phagocytosis and other cellular functions appear to be important contributors to RTS,S immunity. METHODS We studied a phase IIb trial of RTS,S/AS02 conducted in young children in malaria-endemic regions of Mozambique. We evaluated the induction of antibodies targeting the circumsporozoite protein (CSP, vaccine antigen) that interact with Fcγ-receptors (FcRγs) and promote phagocytosis (neutrophils, monocytes, THP-1 cells), antibody-dependent respiratory burst (ADRB) by neutrophils, and natural killer (NK) cell activity, as well as the temporal kinetics of responses over 5 years of follow-up (ClinicalTrials.gov registry number NCT00197041). RESULTS RTS,S vaccination induced CSP-specific IgG with FcγRIIa and FcγRIII binding activity and promoted phagocytosis by neutrophils, THP-1 monocytes, and primary human monocytes, neutrophil ADRB activity, and NK cell activation. Responses were highly heterogenous among children, and the magnitude of neutrophil phagocytosis by antibodies was relatively modest, which may reflect modest vaccine efficacy. Induction of functional antibodies was lower among children with higher malaria exposure. Functional antibody magnitude and the functional activity of antibodies largely declined within a year post-vaccination, and decay were highest in the first 6 months, consistent with the decline in vaccine efficacy over that time. Decay rates varied for different antibody parameters and decay was slower for neutrophil phagocytosis. Biostatistical modelling suggested IgG1 and IgG3 contribute in promoting FcγR binding and phagocytosis, and IgG targeting the NANP-repeat and C-terminal regions CSP were similarly important for functional activities. CONCLUSIONS Results provide new insights to understand the modest and time-limited efficacy of RTS,S in children and the induction of antibody functional activities. Improving the induction and maintenance of antibodies that promote phagocytosis and cellular functions, and combating the negative effect of malaria exposure on vaccine responses are potential strategies for improving RTS,S efficacy and longevity.
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Affiliation(s)
- Gaoqian Feng
- Burnet Institute, Melbourne, Australia.,Department of Medicine, The University of Melbourne, Melbourne, Australia
| | - Liriye Kurtovic
- Burnet Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Australia
| | - Paul A Agius
- Burnet Institute, Melbourne, Australia.,Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Australia.,Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Elizabeth H Aitken
- Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Jahit Sacarlal
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,Faculdade de Medicina, Universidade Eduardo Mondlane (UEM), Maputo, Mozambique
| | - Bruce D Wines
- Burnet Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Australia.,Department of Pathology, The University of Melbourne, Melbourne, Australia
| | - P Mark Hogarth
- Burnet Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Australia.,Department of Pathology, The University of Melbourne, Melbourne, Australia
| | - Stephen J Rogerson
- Department of Medicine, The University of Melbourne, Melbourne, Australia.,Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Freya J I Fowkes
- Burnet Institute, Melbourne, Australia.,Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Australia.,Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Carlota Dobaño
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,ISGlobal, Hospital Clínic Universitat de Barcelona, Barcelona, Catalonia, Spain.,CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - James G Beeson
- Burnet Institute, Melbourne, Australia. .,Department of Medicine, The University of Melbourne, Melbourne, Australia. .,Department of Microbiology, Monash University, Clayton, Australia.
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15
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Mohamed NS, AbdElbagi H, Elsadig AR, Ahmed AE, Mohammed YO, Elssir LT, Elnour MAB, Ali Y, Ali MS, Altahir O, Abubakr M, Siddig EE, Ahmed A, Omer RA. Assessment of genetic diversity of Plasmodium falciparum circumsporozoite protein in Sudan: the RTS,S leading malaria vaccine candidate. Malar J 2021; 20:436. [PMID: 34758827 PMCID: PMC8579544 DOI: 10.1186/s12936-021-03971-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/01/2021] [Indexed: 11/20/2022] Open
Abstract
Background The currently used malaria vaccine, RTS,S, is designed based on the Plasmodium falciparum circumsporozoite protein (PfCSP). The pfcsp gene, besides having different polymorphic patterns, can vary between P. falciparum isolates due to geographical origin and host immune response. Such aspects are essential when considering the deployment of the RTS,S vaccine in a certain region. Therefore, this study assessed the genetic diversity of P. falciparum in Sudan based on the pfcsp gene by investigating the diversity at the N-terminal, central repeat, and the C-terminal regions. Methods A cross-sectional molecular study was conducted; P. falciparum isolates were collected from different health centres in Khartoum State between January and December 2019. During the study period, a total of 261 febrile patients were recruited. Malaria diagnosis was made by expert microscopists using Giemsa-stained thick and thin blood films. DNA samples were examined by the semi-nested polymerase chain reaction (PCR). Single clonal infection of the confirmed P. falciparum cases, were used to amplify the pfcsp gene. The amplified amplicons of pfcsp have been sequenced using the Sanger dideoxy method. The obtained sequences of pfcsp nucleotide diversity parameters including the numbers of haplotypes (Hap), haplotypes diversity (Hapd), the average number of nucleotide differences between two sequences (p), and the numbers of segregating sites (S) were obtained. The haplotype networks were constructed using the online tcsBU software. Natural selection theory was also tested on pfcsp using Fuand Li’s D, Fuand Li’s F statistics, and Tajima’s D test using DnaSP. Results In comparison with the different pfcsp reference strains, the Sudanese isolates showed high similarity with other African isolates. The results of the N-terminal region showed the presence of 2 different haplotypes with a Hapd of 0.425 ± 0.00727. The presence of the unique insertion of NNNGDNGREGKDEDKRDGNN was reported. The KLKQP motif was conserved in all the studied isolates. At the central repeat region, 11 haplotypes were seen with a Hapd of 0.779 ± 0.00097. The analysis of the genetic diversity in the C-terminal region showed the presence of 10 haplotypes with a Hapd of 0.457 ± 0.073. Several non-synonymous amino acids changes were also seen at the Th2R and the Th3R T-cell epitope regions including T317K, E317K, Q318E, K321N, I322K, T322K, R322K, K324Q, I327L, G352N, S354P, R355K, N356D, Q357E, and E361A. Conclusions In this study, the results indicated a high conservation at the pfcsp gene. This may further contribute in understanding the genetic polymorphisms of P. falciparum prior to the deployment of the RTS,S vaccine in Sudan.
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Affiliation(s)
- Nouh Saad Mohamed
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan. .,Molecular Biology Unit, Sirius Training and Research Centre, Khartoum, Sudan.
| | - Hanadi AbdElbagi
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum, Sudan
| | | | | | - Yassir Osman Mohammed
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Lubna Taj Elssir
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Mohammed-Ahmed B Elnour
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Yousif Ali
- Health Emergencies and Epidemics Control General Directorate, Sudan Federal Ministry of Health, Khartoum, Sudan
| | - Mohamed S Ali
- Faculty of Medicine, EL-Neelain University, Khartoum, Sudan
| | - Omnia Altahir
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Mustafa Abubakr
- Department of the Integrated Vector Management (IVM), Federal Ministry of Health, Khartoum, Sudan
| | | | - Ayman Ahmed
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum, Sudan
| | - Rihab Ali Omer
- Pediatric Epidemiology, Clinic and Polyclinic for Child and Adolescent Medicine, Medical Faculty, University of Leipzig, Leipzig, Germany
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16
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Das J, Fallon JK, Yu TC, Michell A, Suscovich TJ, Linde C, Natarajan H, Weiner J, Coccia M, Gregory S, Ackerman ME, Bergmann-Leitner E, Fontana L, Dutta S, Lauffenburger DA, Jongert E, Wille-Reece U, Alter G. Delayed fractional dosing with RTS,S/AS01 improves humoral immunity to malaria via a balance of polyfunctional NANP6- and Pf16-specific antibodies. MED 2021; 2:1269-1286.e9. [DOI: 10.1016/j.medj.2021.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 07/01/2021] [Accepted: 10/07/2021] [Indexed: 02/06/2023]
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17
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Seaton KE, Spreng RL, Abraha M, Reichartz M, Rojas M, Feely F, Huntwork RHC, Dutta S, Mudrak SV, Alam SM, Gregory S, Jongert E, Coccia M, Ulloa-Montoya F, Wille-Reece U, Tomaras GD, Dennison SM. Subclass and avidity of circumsporozoite protein specific antibodies associate with protection status against malaria infection. NPJ Vaccines 2021; 6:110. [PMID: 34462438 PMCID: PMC8405700 DOI: 10.1038/s41541-021-00372-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 07/30/2021] [Indexed: 12/19/2022] Open
Abstract
RTS,S/AS01 is an advanced pre-erythrocytic malaria vaccine candidate with demonstrated vaccine efficacy up to 86.7% in controlled human malaria infection (CHMI) studies; however, reproducible immune correlates of protection (CoP) are elusive. To identify candidates of humoral correlates of vaccine mediated protection, we measured antibody magnitude, subclass, and avidity for Plasmodium falciparum (Pf) circumsporozoite protein (CSP) by multiplex assays in two CHMI studies with varying RTS,S/AS01B vaccine dose and timing regimens. Central repeat (NANP6) IgG1 magnitude correlated best with protection status in univariate analyses and was the most predictive for protection in a multivariate model. NANP6 IgG3 magnitude, CSP IgG1 magnitude, and total serum antibody dissociation phase area-under-the-curve for NANP6, CSP, NPNA3, and N-interface binding were also associated with protection status in the regimen adjusted univariate analysis. Identification of multiple immune response features that associate with protection status, such as antibody subclasses, fine specificity and avidity reported here may accelerate development of highly efficacious vaccines against P. falciparum.
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Grants
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- OPP1151372, OPP12109388 Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- Bill and Melinda Gates Foundation (Bill & Melinda Gates Foundation)
- United States Department of Defense | United States Army | Army Medical Command | Walter Reed Army Institute of Research (WRAIR)
- PATH Malaria Vaccine Initiative
- GlaxoSmithKline (GlaxoSmithKline plc.)
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Affiliation(s)
- Kelly E Seaton
- Duke Human Vaccine Institute, Durham, NC, USA.
- Duke Center for Human Systems Immunology, Durham, NC, USA.
- Duke University Department of Surgery, Durham, NC, USA.
| | - Rachel L Spreng
- Duke Human Vaccine Institute, Durham, NC, USA.
- Duke Center for Human Systems Immunology, Durham, NC, USA.
| | - Milite Abraha
- Duke Human Vaccine Institute, Durham, NC, USA
- Duke Center for Human Systems Immunology, Durham, NC, USA
- Duke University Department of Surgery, Durham, NC, USA
| | - Matthew Reichartz
- Duke Human Vaccine Institute, Durham, NC, USA
- Duke Center for Human Systems Immunology, Durham, NC, USA
- Duke University Department of Surgery, Durham, NC, USA
| | | | - Frederick Feely
- Duke Human Vaccine Institute, Durham, NC, USA
- Duke Center for Human Systems Immunology, Durham, NC, USA
- Duke University Department of Surgery, Durham, NC, USA
| | - Richard H C Huntwork
- Duke Human Vaccine Institute, Durham, NC, USA
- Duke Center for Human Systems Immunology, Durham, NC, USA
- Duke University Department of Surgery, Durham, NC, USA
| | - Sheetij Dutta
- Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Sarah V Mudrak
- Duke Human Vaccine Institute, Durham, NC, USA
- Duke Center for Human Systems Immunology, Durham, NC, USA
- Duke University Department of Surgery, Durham, NC, USA
| | - S Munir Alam
- Duke Human Vaccine Institute, Durham, NC, USA
- Duke University Department of Pathology, Durham, NC, USA
| | - Scott Gregory
- PATH's Malaria Vaccine Initiative, Washington, DC, USA
| | | | | | | | - Ulrike Wille-Reece
- PATH's Malaria Vaccine Initiative, Washington, DC, USA
- GSK, Rockville, MD, USA
| | - Georgia D Tomaras
- Duke Human Vaccine Institute, Durham, NC, USA.
- Duke Center for Human Systems Immunology, Durham, NC, USA.
- Duke University Department of Surgery, Durham, NC, USA.
- Duke University Department of Immunology, Durham, NC, USA.
- Duke University Department of Molecular Genetics and Microbiology, Durham, NC, USA.
| | - S Moses Dennison
- Duke Human Vaccine Institute, Durham, NC, USA.
- Duke Center for Human Systems Immunology, Durham, NC, USA.
- Duke University Department of Surgery, Durham, NC, USA.
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18
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Lucinde RK, Ong'ayo G, Houlihan C, Bottomley C, Goldblatt D, Scott JAG, Gallagher KE. Pneumococcal conjugate vaccine dose-ranging studies in humans: A systematic review. Vaccine 2021; 39:5095-5105. [PMID: 34340858 PMCID: PMC7613540 DOI: 10.1016/j.vaccine.2021.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 11/01/2022]
Abstract
BACKGROUND Streptococcus pneumoniae is one of the most common bacterial pathogens of infants and young children. Antibody responses against the pneumococcal polysaccharide capsule are the basis of vaccine-mediated protection. We examined the relationship between the dose of polysaccharide in pneumococcal conjugate vaccines (PCVs) and immunogenicity. METHODS A systematic search of English publications that evaluated the immunogenicity of varying doses of pneumococcal conjugate vaccines was performed in Medline and Embase (Ovid Sp) databases in August 2019. We included only articles that involved administration of pneumococcal conjugate vaccine in humans and assessed the immunogenicity of more than one serotype-specific saccharide dose. Results were synthesised descriptively due to the heterogeneity of product valency, product content and vaccine schedule. RESULTS We identified 1691 articles after de-duplication; 9 studies met our inclusion criteria; 2 in adults, 6 in children and 1 in both. Doses of polysaccharide evaluated ranged from 0.44 mcg to 17.6 mcg. In infants, all doses tested elicited IgG geometric mean concentrations (GMCs) above the established correlate of protection (COP; 0.35 mcg/ml). A month after completion of the administered vaccine schedule, 95% confidence intervals of only three out of all the doses evaluated had GMCs that crossed below the COP. In the adult studies, all adults achieved GMCs that would be considered protective in children who have received 3 standard vaccine doses. CONCLUSION For some products, the mean antibody concentrations induced against some pneumococcal serotypes increased with increasing doses of the polysaccharide conjugate, but for other serotypes, there were no clear dose-response relationships or the dose response curves were negative. Fractional doses of polysaccharide which contain less than is included in currently distributed formulations may be useful in the development of higher valency vaccines, or dose-sparing delivery for paediatric use.
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Affiliation(s)
- R K Lucinde
- KEMRI-Wellcome Trust Research Programme (KWTRP), Centre for Geographic Medical Research - Coast (CGMRC), Kilifi, Kenya.
| | - G Ong'ayo
- KEMRI-Wellcome Trust Research Programme (KWTRP), Centre for Geographic Medical Research - Coast (CGMRC), Kilifi, Kenya
| | - C Houlihan
- Division of Infection and Immunity, University College London, London, UK
| | - C Bottomley
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, UK
| | - D Goldblatt
- Great Ormond Street Institute of Child Health, University College London, UK
| | - J A G Scott
- KEMRI-Wellcome Trust Research Programme (KWTRP), Centre for Geographic Medical Research - Coast (CGMRC), Kilifi, Kenya; Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, UK
| | - K E Gallagher
- KEMRI-Wellcome Trust Research Programme (KWTRP), Centre for Geographic Medical Research - Coast (CGMRC), Kilifi, Kenya; Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, UK
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19
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Pirahmadi S, Zakeri S, Djadid ND, Mehrizi AA. A review of combination adjuvants for malaria vaccines: a promising approach for vaccine development. Int J Parasitol 2021; 51:699-717. [PMID: 33798560 DOI: 10.1016/j.ijpara.2021.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 12/18/2020] [Accepted: 01/28/2021] [Indexed: 01/16/2023]
Abstract
It is obvious that there is a critical need for an efficient malaria vaccine to accelerate malaria eradication. Currently, recombinant subunit vaccination against malaria using proteins and peptides is gaining attention. However, one of the major drawbacks of this approach is the lack of an efficient and durable immune response. Therefore, subunit vaccines require adjuvants to make the vaccine sufficiently immunogenic. Considering the history of the RTS,S vaccine, it seems likely that no single adjuvant is capable of eliciting all the protective immune responses required in many malarial subunit vaccines and the use of combination adjuvants will be increasingly important as the science of malaria vaccines advances. In light of this, it appears that identifying the most effective mixture of adjuvants with minimal adverse effects offers tremendous opportunities in improving the efficacy of vaccines against malaria. Owing to the importance of a multi-adjuvanted approach in subunit malaria vaccine development, this review paper outlines some of the best known combination adjuvants used in malaria subunit vaccines, focusing on their proposed mechanisms of action, their immunological properties, and their notable results. The aim of the present review is to consolidate these findings to aid the application of these combination adjuvants in experimental malaria vaccines.
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Affiliation(s)
- Sakineh Pirahmadi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran.
| | - Navid D Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Akram A Mehrizi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
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20
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Eacret JS, Parzych EM, Gonzales DM, Burns JM. Inclusion of an Optimized Plasmodium falciparum Merozoite Surface Protein 2-Based Antigen in a Trivalent, Multistage Malaria Vaccine. THE JOURNAL OF IMMUNOLOGY 2021; 206:1817-1831. [PMID: 33789984 DOI: 10.4049/jimmunol.2000927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 02/08/2021] [Indexed: 11/19/2022]
Abstract
Plasmodium falciparum merozoite surface protein (PfMSP)2 is a target of parasite-neutralizing Abs. Inclusion of recombinant PfMSP2 (rPfMSP2) as a component of a multivalent malaria vaccine is of interest, but presents challenges. Previously, we used the highly immunogenic PfMSP8 as a carrier to enhance production and/or immunogenicity of malaria vaccine targets. In this study, we exploited the benefits of rPfMSP8 as a carrier to optimize a rPfMSP2-based subunit vaccine. rPfMSP2 and chimeric rPfMSP2/8 vaccines produced in Escherichia coli were evaluated in comparative immunogenicity studies in inbred (CB6F1/J) and outbred (CD1) mice, varying the dose and adjuvant. Immunization of mice with both rPfMSP2-based vaccines elicited high-titer anti-PfMSP2 Abs that recognized the major allelic variants of PfMSP2. Vaccine-induced T cells recognized epitopes present in both PfMSP2 and the PfMSP8 carrier. Competition assays revealed differences in Ab specificities induced by the two rPfMSP2-based vaccines, with evidence of epitope masking by rPfMSP2-associated fibrils. In contrast to aluminum hydroxide (Alum) as adjuvant, formulation of rPfMSP2 vaccines with glucopyranosyl lipid adjuvant-stable emulsion, a synthetic TLR4 agonist, elicited Th1-associated cytokines, shifting production of Abs to cytophilic IgG subclasses. The rPfMSP2/8 + glucopyranosyl lipid adjuvant-stable emulsion formulation induced significantly higher Ab titers with superior durability and capacity to opsonize P. falciparum merozoites for phagocytosis. Immunization with a trivalent vaccine including PfMSP2/8, PfMSP1/8, and the P. falciparum 25 kDa sexual stage antigen fused to PfMSP8 (Pfs25/8) induced high levels of Abs specific for epitopes in each targeted domain, with no evidence of antigenic competition. These results are highly encouraging for the addition of rPfMSP2/8 as a component of an efficacious, multivalent, multistage malaria vaccine.
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Affiliation(s)
- Jacqueline S Eacret
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Elizabeth M Parzych
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Donna M Gonzales
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129
| | - James M Burns
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129
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21
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Kurtovic L, Boyle MJ, Beeson JG. Epitope masking may limit antibody boosting to malaria vaccines. Immunol Cell Biol 2020; 99:126-129. [PMID: 33152796 DOI: 10.1111/imcb.12415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We discuss the study by McNamara et al., who report that low levels of antigen-specific antibodies in serum can limit the boosting of antibody and B-cell responses following immunization with live attenuated malaria sporozoites.
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Affiliation(s)
- Liriye Kurtovic
- Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Michelle J Boyle
- Burnet Institute, Melbourne, VIC, Australia.,QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia.,Central Clinical School and Department of Microbiology, Monash University, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
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22
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Profiles of Plasmodium falciparum infections detected by microscopy through the first year of life in Kintampo a high transmission area of Ghana. PLoS One 2020; 15:e0240814. [PMID: 33075074 PMCID: PMC7571695 DOI: 10.1371/journal.pone.0240814] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 10/02/2020] [Indexed: 11/24/2022] Open
Abstract
Although malaria mortality among children under five years of age is high, the characteristics of their infection patterns are not well described. The aim of this study was to examine the longitudinal sequence pattern of Plasmodium falciparum infections in the first year of life within a birth cohort in Kintampo, Ghana (N = 1855). Infants were monitored at home with monthly sampling and also at the clinic for any febrile illness between 2008 and 2011. Light microscopy was performed on monthly scheduled visits and febrile ill visits over twelve months of follow-ups (n = 19231). Microscopy-positive visits accompanied with or without symptoms were rare during the first five months of life but were common from six to twelve months of age. Among 1264 infants with microscopy data over a minimum of eight monthly visits and also throughout in sick visits, some were microscopy negative (36%), and others positive: only-symptomatic (35%), alternating (22%) and only-asymptomatic (7%). The median age of microscopic infection was seven months for the alternating group and eight months for both the only-symptomatic and only-asymptomatic groups. The alternating group had the highest cumulative incidence of microscopic infections, the lowest age at first infection and 87 different infection patterns. Parasite densities detected by microscopy were significantly higher for symptomatic versus asymptomatic infection. We conclude that infants in malaria endemic areas experience diverse infection profiles throughout their first year of life. Further investigations should include submicroscopic reservoir and may shed more light on the factors that determine susceptibility to malaria during infancy.
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23
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McCall MBB, Yap XZ, Bousema T. Optimizing RTS,S Vaccination Strategies: Give It Your Best Parting Shot. J Infect Dis 2020; 222:1581-1584. [DOI: 10.1093/infdis/jiaa423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 11/14/2022] Open
Affiliation(s)
- Matthew B B McCall
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Xi Zen Yap
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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24
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Thompson HA, Hogan AB, Walker PGT, White MT, Cunnington AJ, Ockenhouse CF, Ghani AC. Modelling the roles of antibody titre and avidity in protection from Plasmodium falciparum malaria infection following RTS,S/AS01 vaccination. Vaccine 2020; 38:7498-7507. [PMID: 33041104 PMCID: PMC7607256 DOI: 10.1016/j.vaccine.2020.09.069] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 08/21/2020] [Accepted: 09/24/2020] [Indexed: 12/16/2022]
Abstract
Models capturing key malaria life-cycle stages can help us evaluate vaccine candidates. Model fitting revealed antibody avidity to be an important determinant of RTS,S vaccine efficacy. High avidity and titre were associated with increased levels of vaccine efficacy. Did not identify any thresholds of protection for either immune marker.
Anti-circumsporozoite antibody titres have been established as an essential indicator for evaluating the immunogenicity and protective capacity of the RTS,S/AS01 malaria vaccine. However, a new delayed-fractional dose regime of the vaccine was recently shown to increase vaccine efficacy, from 62.5% (95% CI 29.4–80.1%) under the original dosing schedule to 86.7% (95% CI, 66.8–94.6%) without a corresponding increase in antibody titres. Here we reanalyse the antibody data from this challenge trial to determine whether IgG avidity may help to explain efficacy better than IgG titre alone by adapting a within-host mathematical model of sporozoite inoculation. We demonstrate that a model incorporating titre and avidity provides a substantially better fit to the data than titre alone. These results also suggest that in individuals with a high antibody titre response that also show high avidity (both metrics in the top tercile of observed values) delayed-fractional vaccination provided near perfect protection upon first challenge (98.2% [95% Credible Interval 91.6–99.7%]). This finding suggests that the quality of the vaccine induced antibody response is likely to be an important determinant in the development of highly efficacious pre-erythrocytic vaccines against malaria.
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Affiliation(s)
- Hayley A Thompson
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom.
| | - Alexandra B Hogan
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Patrick G T Walker
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Michael T White
- Malaria: Parasites and Hosts, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | | | | | - Azra C Ghani
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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25
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Marques-da-Silva C, Peissig K, Kurup SP. Pre-Erythrocytic Vaccines against Malaria. Vaccines (Basel) 2020; 8:vaccines8030400. [PMID: 32708179 PMCID: PMC7565498 DOI: 10.3390/vaccines8030400] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/09/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022] Open
Abstract
Malaria, caused by the protozoan Plasmodium, is a devastating disease with over 200 million new cases reported globally every year. Although immunization is arguably the best strategy to eliminate malaria, despite decades of research in this area we do not have an effective, clinically approved antimalarial vaccine. The current impetus in the field is to develop vaccines directed at the pre-erythrocytic developmental stages of Plasmodium, utilizing novel vaccination platforms. We here review the most promising pre-erythrocytic stage antimalarial vaccine candidates.
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Affiliation(s)
- Camila Marques-da-Silva
- Center for Tropical and Emerging Global Diseases, The University of Georgia, Athens, GA 30602, USA; (C.M.-d.-S.); (K.P.)
- Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA
| | - Kristen Peissig
- Center for Tropical and Emerging Global Diseases, The University of Georgia, Athens, GA 30602, USA; (C.M.-d.-S.); (K.P.)
- Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA
| | - Samarchith P. Kurup
- Center for Tropical and Emerging Global Diseases, The University of Georgia, Athens, GA 30602, USA; (C.M.-d.-S.); (K.P.)
- Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA
- Correspondence:
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26
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Sanchez L, Vidal M, Jairoce C, Aguilar R, Ubillos I, Cuamba I, Nhabomba AJ, Williams NA, Díez-Padrisa N, Cavanagh D, Angov E, Coppel RL, Gaur D, Beeson JG, Dutta S, Aide P, Campo JJ, Moncunill G, Dobaño C. Antibody responses to the RTS,S/AS01 E vaccine and Plasmodium falciparum antigens after a booster dose within the phase 3 trial in Mozambique. NPJ Vaccines 2020; 5:46. [PMID: 32550014 PMCID: PMC7272643 DOI: 10.1038/s41541-020-0192-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 05/07/2020] [Indexed: 01/08/2023] Open
Abstract
The RTS,S/AS01E vaccine has shown consistent but partial vaccine efficacy in a pediatric phase 3 clinical trial using a 3-dose immunization schedule. A fourth-dose 18 months after the primary vaccination was shown to restore the waning efficacy. However, only total IgG against the immunodominant malaria vaccine epitope has been analyzed following the booster. To better characterize the magnitude, nature, and longevity of the immune response to the booster, we measured levels of total IgM, IgG, and IgG1-4 subclasses against three constructs of the circumsporozoite protein (CSP) and the hepatitis B surface antigen (HBsAg, also present in RTS,S) by quantitative suspension array technology in 50 subjects in the phase 3 trial in Manhiça, Mozambique. To explore the impact of vaccination on naturally acquired immune responses, we measured antibodies to P. falciparum antigens not included in RTS,S. We found increased IgG, IgG1, IgG3 and IgG4, but not IgG2 nor IgM, levels against vaccine antigens 1 month after the fourth dose. Overall, antibody responses to the booster dose were lower than the initial peak response to primary immunization and children had higher IgG and IgG1 levels than infants. Higher anti-Rh5 IgG and IgG1-4 levels were detected after the booster dose, suggesting that RTS,S partial protection could increase some blood stage antibody responses. Our work shows that the response to the RTS,S/AS01E booster dose is different from the primary vaccine immune response and highlights the dynamic changes in subclass antibody patterns upon the vaccine booster and with acquisition of adaptive immunity to malaria.
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Affiliation(s)
- Lina Sanchez
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain.,UnivLyon, Université Claude Bernard Lyon 1, 69100 Villeurbanne, France
| | - Marta Vidal
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain
| | - Chenjerai Jairoce
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Ruth Aguilar
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain
| | - Itziar Ubillos
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain
| | - Inocencia Cuamba
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | | | - Nana Aba Williams
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain
| | - Núria Díez-Padrisa
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain
| | - David Cavanagh
- Institute of Immunology & Infection Research and Centre for Immunity, Infection & Evolution, Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh, UK
| | - Evelina Angov
- U.S. Military Malaria Vaccine Program, Walter Reed Army Institute of Research (WRAIR), Silver Spring, MD USA
| | - Ross L Coppel
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC Australia
| | - Deepak Gaur
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India.,Laboratory of Malaria and Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | | | - Sheetij Dutta
- U.S. Military Malaria Vaccine Program, Walter Reed Army Institute of Research (WRAIR), Silver Spring, MD USA
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Joseph J Campo
- UnivLyon, Université Claude Bernard Lyon 1, 69100 Villeurbanne, France.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Gemma Moncunill
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Carlota Dobaño
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
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27
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Kurtovic L, Atre T, Feng G, Wines BD, Chan JA, Boyle MJ, Drew DR, Hogarth PM, Fowkes FJI, Bergmann-Leitner ES, Beeson JG. Multi-functional antibodies are induced by the RTS,S malaria vaccine and associated with protection in a phase I/IIa trial. J Infect Dis 2020; 224:1128-1138. [PMID: 32236404 PMCID: PMC8514181 DOI: 10.1093/infdis/jiaa144] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/30/2020] [Indexed: 01/24/2023] Open
Abstract
Background RTS,S is the leading malaria vaccine candidate but only confers partial efficacy against malaria in children. RTS,S is based on the major Plasmodium falciparum sporozoite surface antigen, circumsporozoite protein (CSP). The induction of anti-CSP antibodies is important for protection; however, it is unclear how these protective antibodies function. Methods We quantified the induction of functional anti-CSP antibody responses in healthy malaria-naive adults (N = 45) vaccinated with RTS,S/AS01. This included the ability to mediate effector functions via the fragment crystallizable (Fc) region, such as interacting with human complement proteins and Fcγ-receptors (FcγRs) that are expressed on immune cells, which promote various immunological functions. Results Our major findings were (1) RTS,S-induced antibodies mediated Fc-dependent effector functions, (2) functional antibodies were generally highest after the second vaccine dose, (3) functional antibodies targeted multiple regions of CSP, (4) participants with higher levels of functional antibodies had a reduced probability of developing parasitemia following homologous challenge (P < .05), and (5) nonprotected subjects had higher levels of anti-CSP IgM. Conclusions Our data suggest a role for Fc-dependent antibody effector functions in RTS,S-induced immunity. Enhancing the induction of these functional activities may be a strategy to improve the protective efficacy of RTS,S or other malaria vaccines. Clinical Trials Registration NCT00075049
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Affiliation(s)
- Liriye Kurtovic
- Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Tanmaya Atre
- Malaria Vaccine Branch, US Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, United States
| | | | - Bruce D Wines
- Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia.,Department of Clinical Pathology, The University of Melbourne, Melbourne, Australia
| | - Jo-Anne Chan
- Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Michelle J Boyle
- Burnet Institute, Melbourne, Australia.,QIMR Berghofer, Herston, Australia
| | | | - P Mark Hogarth
- Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia.,Department of Clinical Pathology, The University of Melbourne, Melbourne, Australia
| | - Freya J I Fowkes
- Burnet Institute, Melbourne, Australia.,Department of Epidemiology and Preventative Medicine and Department of Infectious Diseases, Monash University, Melbourne, Australia.,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Elke S Bergmann-Leitner
- Malaria Vaccine Branch, US Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, United States
| | - James G Beeson
- Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia.,Department of Microbiology, Monash University, Clayton, Australia.,Department of Medicine, The University of Melbourne, Parkville, Australia
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28
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Asante KP, Ansong D, Kaali S, Adjei S, Lievens M, Nana Badu L, Agyapong Darko P, Boakye Yiadom Buabeng P, Boahen O, Maria Rettig T, Agutu C, Benard Ekow Harrison S, Ntiamoah Y, Adomako Anim J, Adeniji E, Agordo Dornudo A, Gvozdenovic E, Dosoo D, Sambian D, Owusu-Boateng H, Ato Wilson E, Prempeh F, Vandoolaeghe P, Schuerman L, Owusu-Agyei S, Agbenyega T, Ofori-Anyinam O. Immunogenicity and safety of the RTS,S/AS01 malaria vaccine co-administered with measles, rubella and yellow fever vaccines in Ghanaian children: A phase IIIb, multi-center, non-inferiority, randomized, open, controlled trial. Vaccine 2020; 38:3411-3421. [PMID: 32192811 DOI: 10.1016/j.vaccine.2020.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND To optimize vaccine implementation visits for young children, it could be efficient to administer the first RTS,S/AS01 malaria vaccine dose during the Expanded Programme on Immunization (EPI) visit at 6 months of age together with Vitamin A supplementation and the third RTS,S/AS01 dose on the same day as yellow fever (YF), measles and rubella vaccines at 9 months of age. We evaluated the safety and immunogenicity of RTS,S/AS01 when co-administered with YF and combined measles-rubella (MR) vaccines. METHODS In this phase 3b, open-label, controlled study (NCT02699099), 709 Ghanaian children were randomized (1:1:1) to receive RTS,S/AS01 at 6, 7.5 and 9 months of age, and YF and MR vaccines at 9 or 10.5 months of age (RTS,S coad and RTS,S alone groups, respectively). The third group received YF and MR vaccines at 9 months of age and will receive RTS,S/AS01 at 10.5, 11.5 and 12.5 months of age (Control group). All children received Vitamin A at 6 months of age. Non-inferiority of immune responses to the vaccine antigens was evaluated 1 month following co-administration versus RTS,S/AS01 or EPI vaccines (YF and MR vaccines) alone using pre-defined non-inferiority criteria. Safety was assessed until Study month 4.5. RESULTS Non-inferiority of antibody responses to the anti-circumsporozoite and anti-hepatitis B virus surface antigens when RTS,S/AS01 was co-administered with YF and MR vaccines versus RTS,S/AS01 alone was demonstrated. Non-inferiority of antibody responses to the measles, rubella, and YF antigens when RTS,S/AS01 was co-administered with YF and MR vaccines versus YF and MR vaccines alone was demonstrated. The safety profile of all vaccines was clinically acceptable in all groups. CONCLUSIONS RTS,S/AS01 can be co-administered with Vitamin A at 6 months and with YF and MR vaccines at 9 months of age during EPI visits, without immune response impairment to any vaccine antigen or negative safety effect.
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Affiliation(s)
- Kwaku Poku Asante
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana.
| | - Daniel Ansong
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | - Seyram Kaali
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana.
| | - Samuel Adjei
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | - Marc Lievens
- GSK Vaccines, Avenue Fleming 20, 1300 Wavre, Belgium.
| | - Lydia Nana Badu
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | | | - Patrick Boakye Yiadom Buabeng
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | - Owusu Boahen
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana.
| | - Theresa Maria Rettig
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | - Clara Agutu
- GSK Vaccines, Avenue Fleming 20, 1300 Wavre, Belgium.
| | | | - Yaw Ntiamoah
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | - Japhet Adomako Anim
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana.
| | - Elisha Adeniji
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana.
| | - Albert Agordo Dornudo
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | | | - David Dosoo
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana.
| | - David Sambian
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | - Harry Owusu-Boateng
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | - Elvis Ato Wilson
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana.
| | - Frank Prempeh
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana
| | | | | | - Seth Owusu-Agyei
- Kintampo Health Research Center, Ghana Health Service, PO Box 200, Kintampo, Ghana; London School of Hygiene and Tropical Medicine, UK; University of Health and Allied Sciences, Ho, Ghana.
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science & Technology/Agogo Presbyterian Hospital, P.O. Box 27 Agogo, Asante Akyem, Ghana.
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Molina-Franky J, Cuy-Chaparro L, Camargo A, Reyes C, Gómez M, Salamanca DR, Patarroyo MA, Patarroyo ME. Plasmodium falciparum pre-erythrocytic stage vaccine development. Malar J 2020; 19:56. [PMID: 32013956 PMCID: PMC6998842 DOI: 10.1186/s12936-020-3141-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/25/2020] [Indexed: 12/13/2022] Open
Abstract
Worldwide strategies between 2010 and 2017 aimed at controlling malarial parasites (mainly Plasmodium falciparum) led to a reduction of just 18% regarding disease incidence rates. Many biologically-derived anti-malarial vaccine candidates have been developed to date; this has involved using many experimental animals, an immense amount of work and the investment of millions of dollars. This review provides an overview of the current state and the main results of clinical trials for sporozoite-targeting vaccines (i.e. the parasite stage infecting the liver) carried out by research groups in areas having variable malaria transmission rates. However, none has led to promising results regarding the effective control of the disease, thereby making it necessary to complement such efforts at finding/introducing new vaccine candidates by adopting a multi-epitope, multi-stage approach, based on minimal subunits of the main sporozoite proteins involved in the invasion of the liver.
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Affiliation(s)
- Jessica Molina-Franky
- Health Sciences Faculty, Universidad de Boyacá, Tunja, Colombia.,Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Laura Cuy-Chaparro
- Health Sciences Faculty, Universidad de Boyacá, Tunja, Colombia.,Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Anny Camargo
- Health Sciences Faculty, Universidad de Boyacá, Tunja, Colombia.,Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - César Reyes
- PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia.,Animal Science Faculty, Universidad de Ciencias Aplicadas y Ambientales (U.D.C.A), Bogotá, Colombia.,3D Structures Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Marcela Gómez
- Health Sciences Faculty, Universidad de Boyacá, Tunja, Colombia.,Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - David Ricardo Salamanca
- Health Sciences Faculty, Universidad de Boyacá, Tunja, Colombia.,Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Manuel Alfonso Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia. .,Basic Sciences Department, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia.
| | - Manuel Elkin Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia. .,Medical School, Universidad Nacional de Colombia, Bogotá, Colombia.
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30
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Valéa I, Adjei S, Usuf E, Traore O, Ansong D, Tinto H, Owusu Boateng H, Some AM, Buabeng P, Vekemans J, Kotey A, Vandoolaeghe P, Cullinane M, Traskine M, Ouedraogo F, Sambian D, Lievens M, Tahita MC, Jongert E, Lompo P, Idriss A, Borys D, Ouedraogo S, Prempeh F, Schuerman L, Sorgho H, Agbenyega T. Long-term immunogenicity and immune memory response to the hepatitis B antigen in the RTS,S/AS01 E malaria vaccine in African children: a randomized trial. Hum Vaccin Immunother 2020; 16:1464-1470. [PMID: 31951771 PMCID: PMC7482624 DOI: 10.1080/21645515.2019.1695457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
RTS,S/AS01E malaria vaccine contains the hepatitis B virus surface antigen and may thus serve as a potential hepatitis B vaccine. To evaluate the impact of RTS,S/AS01E when implemented in the Expanded Program of Immunization, infants 8-12 weeks old were randomized to receive either RTS,S/AS01E or a licensed hepatitis B control vaccine (HepB), both co-administered with various combinations of the following childhood vaccines: diphtheria-tetanus-acellular pertussis-Haemophilus influenzae type b, trivalent oral poliovirus, pneumococcal non-typeable Haemophilus influenzae protein D conjugate and human rotavirus vaccine. Long-term persistence of antibodies against the circumsporozoite (CS) protein and hepatitis B surface antigen (HBsAg) were assessed, together with the immune memory response to the HB antigen following a booster dose of HepB vaccine. Subgroups receiving RTS,S or the HepB control vaccine were pooled into RTS,S groups and HepB groups, respectively. One month post-HepB booster vaccination, 100% of participants in the RTS,S groups and 98.3% in the control groups had anti-HBs antibody concentrations ≥10 mIU/mL with the geometric mean concentrations (GMCs) at 46634.7 mIU/mL (95% CI: 40561.3; 53617.6) and 9258.2 mIU/mL (95% CI: 6925.3; 12377.0), respectively. Forty-eight months post-primary vaccination anti-CS antibody GMCs ranged from 2.3 EU/mL to 2.7 EU/mL in the RTS,S groups compared to 1.1 EU/mL in the control groups. Hepatitis B priming with the RTS,S/AS01E vaccine was effective and resulted in a memory response to HBsAg as shown by the robust booster response following an additional dose of HepB vaccine. RTS,S/AS01E when co-administered with PHiD-CV, HRV and other childhood vaccines, had an acceptable safety profile.
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Affiliation(s)
- Innocent Valéa
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso.,IRSS, Centre Muraz , Bobo-Dioulasso, Burkina Faso
| | - Samuel Adjei
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | | | - Ousmane Traore
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso
| | - Daniel Ansong
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | - Halidou Tinto
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso
| | - Harry Owusu Boateng
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | | | - Patrick Buabeng
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | | | - Amos Kotey
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | | | | | | | - Florence Ouedraogo
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso
| | - David Sambian
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | | | - Marc Christian Tahita
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso
| | | | - Palpouguini Lompo
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso
| | - Ali Idriss
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | | | - Sayouba Ouedraogo
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso
| | - Frank Prempeh
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
| | | | - Hermann Sorgho
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé , Nanoro, Burkina Faso
| | - Tsiri Agbenyega
- School of Medical Sciences, KNUST (Agogo Presbyterian Hospital) , Kumasi, Ghana
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Yerushalmi E, Hunt P, Hoorens S, Sauboin C, Smith R. Exploring the Use of a General Equilibrium Method to Assess the Value of a Malaria Vaccine: An Application to Ghana. MDM Policy Pract 2019; 4:2381468319894345. [PMID: 31903422 PMCID: PMC6923699 DOI: 10.1177/2381468319894345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 11/05/2019] [Indexed: 01/16/2023] Open
Abstract
Background. Malaria is an important health and economic burden in
sub-Saharan Africa. Conventional economic evaluations typically consider only
direct costs to the health care system and government budgets. This paper
quantifies the potential impact of malaria vaccination on the wider economy,
using Ghana as an example. Methods. We used a computable general
equilibrium model of the Ghanaian economy to estimate the macroeconomic impact
of malaria vaccination in children under the age of 5, with a vaccine efficacy
of 50% against clinical malaria and 20% against malaria mortality. The model
considered changes in demography and labor productivity, and projected gross
domestic product (GDP) over a time frame of 30 years. Vaccine coverage ranging
from 20% to 100% was compared with a baseline with no vaccination.
Results. Malaria vaccination with 100% coverage was projected
to increase the GDP of Ghana over 30 years by US$6.93 billion (in 2015 prices)
above the baseline without vaccination, equivalent to an increase in annual GDP
growth of 0.5%. Projected GDP per capita would increase in the first year due to
immediate reductions in time lost from work by adults caring for children with
malaria, then decrease for several years as reductions in child mortality
increase the number of dependent children, then show a sustained increase after
Year 11 due to long-term productivity improvements in adults resulting from
fewer malaria episodes in childhood. Conclusion. Investing in
improving childhood health by vaccinating against malaria could result in
substantial long-term macroeconomic benefits when these children enter the
workforce as adults. These macroeconomic benefits are not captured by
conventional economic evaluations and constitute an important potential benefit
of vaccination.
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Affiliation(s)
- Erez Yerushalmi
- Birmingham City Business School, Birmingham City University, Birmingham, UK
| | | | | | | | - Richard Smith
- College of Medicine and Health, University of Exeter, Exeter, UK
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32
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Safety and immunogenicity of the RTS,S/AS01 malaria vaccine in infants and children identified as HIV-infected during a randomized trial in sub-Saharan Africa. Vaccine 2019; 38:897-906. [PMID: 31708182 PMCID: PMC7613311 DOI: 10.1016/j.vaccine.2019.10.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/22/2019] [Accepted: 10/25/2019] [Indexed: 01/24/2023]
Abstract
Background We assessed the safety and immunogenicity of the RTS,S/AS01 malaria vaccine in a subset of children identified as HIV-infected during a large phase III randomized controlled trial conducted in seven sub-Saharan African countries. Methods Infants 6–12 weeks and children 5–17 months old were randomized to receive 4 RTS,S/AS01 doses (R3R group), 3 RTS,S/AS01 doses plus 1 comparator vaccine dose (R3C group), or 4 comparator vaccine doses (C3C group) at study months 0, 1, 2 and 20. Infants and children with WHO stage III/IV HIV disease were excluded but HIV testing was not routinely performed on all participants; our analyses included children identified as HIV-infected based on medical history or clinical suspicion and confirmed by polymerase chain reaction or antibody testing. Serious adverse events (SAEs) and anti-circumsporozoite (CS) antibodies were assessed. Results Of 15459 children enrolled in the trial, at least 1953 were tested for HIV and 153 were confirmed as HIV-infected (R3R: 51; R3C: 54; C3C: 48). Among these children, SAEs were reported for 92.2% (95% CI: 81.1–97.8) in the R3R, 85.2% (72.9–93.4) in the R3C and 87.5% (74.8–95.3) in the C3C group over a median follow-up of 39.3, 39.4 and 38.3 months, respectively. Fifteen HIV-infected participants in each group (R3R: 29.4%, R3C: 27.8%, C3C: 31.3%) died during the study. No deaths were considered vaccination-related. In a matched case-control analysis, 1 month post dose 3 anti-CS geometric mean antibody concentrations were 193.3 EU/mL in RTS,S/AS01-vaccinated HIV-infected children and 491.5 EU/mL in RTS,S/ AS01-vaccinated immunogenicity controls with unknown or negative HIV status (p = 0.0001). Conclusions The safety profile of RTS,S/AS01 in HIV-infected children was comparable to that of the comparator (meningococcal or rabies) vaccines. RTS,S/AS01 was immunogenic in HIV-infected children but antibody concentrations were lower than in children with an unknown or negative HIV status.
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33
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Guerra Mendoza Y, Garric E, Leach A, Lievens M, Ofori-Anyinam O, Pirçon JY, Stegmann JU, Vandoolaeghe P, Otieno L, Otieno W, Owusu-Agyei S, Sacarlal J, Masoud NS, Sorgho H, Tanner M, Tinto H, Valea I, Mtoro AT, Njuguna P, Oneko M, Otieno GA, Otieno K, Gesase S, Hamel MJ, Hoffman I, Kaali S, Kamthunzi P, Kremsner P, Lanaspa M, Lell B, Lusingu J, Malabeja A, Aide P, Akoo P, Ansong D, Asante KP, Berkley JA, Adjei S, Agbenyega T, Agnandji ST, Schuerman L. Safety profile of the RTS,S/AS01 malaria vaccine in infants and children: additional data from a phase III randomized controlled trial in sub-Saharan Africa. Hum Vaccin Immunother 2019; 15:2386-2398. [PMID: 31012786 PMCID: PMC6816384 DOI: 10.1080/21645515.2019.1586040] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A phase III, double-blind, randomized, controlled trial (NCT00866619) in sub-Saharan Africa showed RTS,S/AS01 vaccine efficacy against malaria. We now present in-depth safety results from this study. 8922 children (enrolled at 5–17 months) and 6537 infants (enrolled at 6–12 weeks) were 1:1:1-randomized to receive 4 doses of RTS,S/AS01 (R3R) or non-malaria control vaccine (C3C), or 3 RTS,S/AS01 doses plus control (R3C). Aggregate safety data were reviewed by a multi-functional team. Severe malaria with Blantyre Coma Score ≤2 (cerebral malaria [CM]) and gender-specific mortality were assessed post-hoc. Serious adverse event (SAE) and fatal SAE incidences throughout the study were 24.2%–28.4% and 1.5%–2.5%, respectively across groups; 0.0%–0.3% of participants reported vaccination-related SAEs. The incidence of febrile convulsions in children was higher during the first 2–3 days post-vaccination with RTS,S/AS01 than with control vaccine, consistent with the time window of post-vaccination febrile reactions in this study (mostly the day after vaccination). A statistically significant numerical imbalance was observed for meningitis cases in children (R3R: 11, R3C: 10, C3C: 1) but not in infants. CM cases were more frequent in RTS,S/AS01-vaccinated children (R3R: 19, R3C: 24, C3C: 10) but not in infants. All-cause mortality was higher in RTS,S/AS01-vaccinated versus control girls (2.4% vs 1.3%, all ages) in our setting with low overall mortality. The observed meningitis and CM signals are considered likely chance findings, that – given their severity – warrant further evaluation in phase IV studies and WHO-led pilot implementation programs to establish the RTS,S/AS01 benefit-risk profile in real-life settings.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Seth Owusu-Agyei
- Kintampo Health Research Center , Kintampo , Ghana.,Diseases Control Department, London School of Hygiene and Tropical Medicine , London , UK
| | - Jahit Sacarlal
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,Faculdade de Medicina, Universidade Eduardo Mondlane (UEM) , Maputo , Mozambique
| | - Nahya Salim Masoud
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania
| | - Hermann Sorgho
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Marcel Tanner
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania.,Swiss Tropical and Public Health Institute , Basel , Switzerland.,Epidemiology and Medical Parasitology department, University of Basel , Basel , Switzerland
| | - Halidou Tinto
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Innocent Valea
- Institut de Recherche en Science de la Santé , Nanoro , Burkina Faso
| | - Ali Takadir Mtoro
- Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam and Ifakara Health Institute , Bagamoyo , Tanzania
| | - Patricia Njuguna
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya.,Pwani University , Kilifi , Kenya.,University of Oxford , Oxford , UK
| | - Martina Oneko
- Kenya Medical Research Institute, Centre for Global Health Research , Kisumu , Kenya
| | | | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research , Kisumu , Kenya
| | - Samwel Gesase
- National Institute for Medical Research , Korogwe , Tanzania
| | - Mary J Hamel
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention , Atlanta , GA , USA
| | - Irving Hoffman
- University of North Carolina Project , Lilongwe , Malawi
| | - Seyram Kaali
- Kintampo Health Research Center , Kintampo , Ghana
| | | | - Peter Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
| | - Miguel Lanaspa
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona , Barcelona , Spain
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
| | - John Lusingu
- National Institute for Medical Research , Korogwe , Tanzania
| | | | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça , Manhiça , Mozambique.,National Institute of Health, Ministry of Health , Maputo , Mozambique
| | - Pauline Akoo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya
| | - Daniel Ansong
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | | | - James A Berkley
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research , Kilifi , Kenya.,University of Oxford , Oxford , UK
| | - Samuel Adjei
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen , Tübingen , Germany
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Beeson JG, Kurtovic L, Dobaño C, Opi DH, Chan JA, Feng G, Good MF, Reiling L, Boyle MJ. Challenges and strategies for developing efficacious and long-lasting malaria vaccines. Sci Transl Med 2019; 11:11/474/eaau1458. [DOI: 10.1126/scitranslmed.aau1458] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/05/2018] [Accepted: 11/02/2018] [Indexed: 12/24/2022]
Abstract
Although there has been major recent progress in malaria vaccine development, substantial challenges remain for achieving highly efficacious and durable vaccines against Plasmodium falciparum and Plasmodium vivax malaria. Greater knowledge of mechanisms and key targets of immunity are needed to accomplish this goal, together with new strategies for generating potent, long-lasting, functional immunity against multiple antigens. Implementation considerations in endemic areas will ultimately affect vaccine effectiveness, so innovations to simplify and enhance delivery are also needed. Whereas challenges remain, recent exciting progress and emerging knowledge promise hope for the future of malaria vaccines.
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Caminade C, McIntyre KM, Jones AE. Impact of recent and future climate change on vector-borne diseases. Ann N Y Acad Sci 2019; 1436:157-173. [PMID: 30120891 PMCID: PMC6378404 DOI: 10.1111/nyas.13950] [Citation(s) in RCA: 217] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/12/2018] [Accepted: 07/17/2018] [Indexed: 12/22/2022]
Abstract
Climate change is one of the greatest threats to human health in the 21st century. Climate directly impacts health through climatic extremes, air quality, sea-level rise, and multifaceted influences on food production systems and water resources. Climate also affects infectious diseases, which have played a significant role in human history, impacting the rise and fall of civilizations and facilitating the conquest of new territories. Our review highlights significant regional changes in vector and pathogen distribution reported in temperate, peri-Arctic, Arctic, and tropical highland regions during recent decades, changes that have been anticipated by scientists worldwide. Further future changes are likely if we fail to mitigate and adapt to climate change. Many key factors affect the spread and severity of human diseases, including mobility of people, animals, and goods; control measures in place; availability of effective drugs; quality of public health services; human behavior; and political stability and conflicts. With drug and insecticide resistance on the rise, significant funding and research efforts must to be maintained to continue the battle against existing and emerging diseases, particularly those that are vector borne.
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Affiliation(s)
- Cyril Caminade
- Department of Epidemiology and Population Health, Institute of Infection and Global HealthUniversity of LiverpoolLiverpoolUK
- NIHR Health Protection Research Unit in Emerging and Zoonotic InfectionsLiverpoolUK
| | - K. Marie McIntyre
- Department of Epidemiology and Population Health, Institute of Infection and Global HealthUniversity of LiverpoolLiverpoolUK
- NIHR Health Protection Research Unit in Emerging and Zoonotic InfectionsLiverpoolUK
| | - Anne E. Jones
- Department of Mathematical SciencesUniversity of LiverpoolLiverpoolUK
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Hogan AB, Winskill P, Verity R, Griffin JT, Ghani AC. Modelling population-level impact to inform target product profiles for childhood malaria vaccines. BMC Med 2018; 16:109. [PMID: 30001708 PMCID: PMC6044028 DOI: 10.1186/s12916-018-1095-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/05/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The RTS,S/AS01 vaccine for Plasmodium falciparum malaria demonstrated moderate efficacy in 5-17-month-old children in phase 3 trials, and from 2018, the vaccine will be evaluated through a large-scale pilot implementation program. Work is ongoing to optimise this vaccine, with higher efficacy for a different schedule demonstrated in a phase 2a challenge study. The objective of our study was to investigate the population-level impact of a modified RTS,S/AS01 schedule and dose amount in order to inform the target product profile for a second-generation malaria vaccine. METHODS We used a mathematical modelling approach as the basis for our study. We simulated the changing anti-circumsporozoite antibody titre following vaccination and related the titre to vaccine efficacy. We then implemented this efficacy profile within an individual-based model of malaria transmission. We compared initial efficacy, duration and dose timing, and evaluated the potential public health impact of a modified vaccine in children aged 5-17 months, measuring clinical cases averted in children younger than 5 years. RESULTS In the first decade of delivery, initial efficacy was associated with a higher reduction in childhood clinical cases compared to vaccine duration. This effect was more pronounced in high transmission settings and was due to the efficacy benefit occurring in younger ages where disease burden is highest. However, the low initial efficacy and long duration schedule averted more cases across all age cohorts if a longer time horizon was considered. We observed an age-shifting effect due to the changing immunological profile in higher transmission settings, in scenarios where initial efficacy was higher, and the fourth dose administered earlier. CONCLUSIONS Our findings indicate that, for an imperfect childhood malaria vaccine with suboptimal efficacy, it may be advantageous to prioritise initial efficacy over duration. We predict that a modified vaccine could outperform the current RTS,S/AS01, although fourth dose timing will affect the age group that derives the greatest benefit. Further, the outcome measure and timeframe over which a vaccine is assessed are important when prioritising vaccine elements. This study provides insight into the most important characteristics of a malaria vaccine for at-risk groups and shows how distinct vaccine properties translate to public health outcomes. These findings may be used to prioritise target product profile elements for second-generation childhood malaria vaccines.
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Affiliation(s)
- Alexandra B. Hogan
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, School of Public Health, St Mary’s Campus, Norfolk Place, London, W2 1PG UK
| | - Peter Winskill
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, School of Public Health, St Mary’s Campus, Norfolk Place, London, W2 1PG UK
| | - Robert Verity
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, School of Public Health, St Mary’s Campus, Norfolk Place, London, W2 1PG UK
| | - Jamie T. Griffin
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, School of Public Health, St Mary’s Campus, Norfolk Place, London, W2 1PG UK
- School of Mathematical Sciences, Queen Mary University London, Mile End Road, London, E1 4NS UK
| | - Azra C. Ghani
- Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, Imperial College London, School of Public Health, St Mary’s Campus, Norfolk Place, London, W2 1PG UK
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Vandoolaeghe P, Schuerman L. [The RTS,S/AS01 malaria vaccine in children aged 5-17 months at first vaccination]. Pan Afr Med J 2018; 30:142. [PMID: 30374388 PMCID: PMC6201624 DOI: 10.11604/pamj.2018.30.142.13152] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 02/08/2018] [Indexed: 11/18/2022] Open
Abstract
Le vaccin antipaludique RTS,S/AS01 a reçu un avis scientifique favorable de l’Agence Européenne des Médicaments (EMA) en Juillet 2015. L’Organisation Mondiale de la Santé (OMS) a recommandé l’introduction pilote de ce vaccin chez des enfants âgés d’au moins 5 mois en utilisant un schéma de vaccination comprenant 3 doses initiales espacées d’au moins un mois et une 4ème dose administrée 15 à 18 mois après la 3ème dose. Des essais cliniques et des modèles mathématiques ont montré que la protection partielle contre le paludisme conférée par le vaccin RTS,S/AS01 pourrait avoir un impact substantiel sur la santé publique si le vaccin est utilisé en association avec d’autres mesures de lutte antipaludique, en particulier dans les zones hautement endémiques. L’impact le plus important a été observé chez les enfants âgés de 5 mois ou plus ayant reçu 4 doses de RTS,S/AS01. Le vaccin sera ensuite évalué en situation réelle afin de déterminer son impact sur la mortalité, son innocuité dans le cadre d’une vaccination de routine, et la faisabilité opérationnelle d’administrer 4 doses du vaccin dont certaines nécessitant de nouveaux contacts dans le calendrier de vaccination. En cas de succès, cela permettra une mise en œuvre à plus grande échelle.
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Safety and Immunogenicity of Seven Dosing Regimens of the Candidate RTS,S/AS01E Malaria Vaccine Integrated Within an Expanded Program on Immunization Regimen: A Phase II, Single-Center, Open, Controlled Trial in Infants in Malawi. Pediatr Infect Dis J 2018; 37:483-491. [PMID: 29432383 DOI: 10.1097/inf.0000000000001937] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND In a phase III trial, the RTS,S/AS01 malaria vaccine produced lower anti-circumsporozoite (CS) antibody titers when co-administered with Expanded Programme on Immunization vaccines (0-, 1- and 2-month schedule) at 6 to 12 weeks compared with 5 to 17 months at first vaccination. Alternative infant immunization schedules within the Expanded Programme on Immunization were investigated. METHODS This phase II, open, single-site (Blantyre, Malawi) trial was conducted in infants 1 to 7 days of age. Subjects were equally randomized across 7 groups to receive 3 doses of RTS,S/AS01E at time points that included ≤7 days, 6, 10, 14 and 26 weeks, and 9 months. All RTS,S/AS01E groups plus a control group (without RTS,S/AS01E) received Bacillus Calmette-Guérin + oral poliovirus vaccine at ≤7 days, diphtheria, tetanus, whole-cell pertussis, hepatitis B and Haemophilus influenzae type b vaccine + oral poliovirus vaccine at 6, 10, and 14 weeks and measles vaccine at 9 months; one RTS,S/AS01E group and the control additionally received hepatitis B vaccination at ≤7 days. Serum anti-CS antibody geometric mean concentration (GMC; enzyme-linked immunosorbent assay) and safety were assessed up to age 18 months. RESULTS Of the 480 infants enrolled, 391 completed the study. No causally related serious adverse event was reported. A higher frequency of fever within 7 days of RTS,S/AS01E vaccination compared with control was observed. Compared with the standard 6-, 10-, 14-week schedule, anti-CS antibody GMC ratios post-dose 3 were significantly higher in the 10-, 14- and 26-week group only (ratio 1.80; 95% confidence interval, 1.24-2.60); RTS,S/AS01E vaccination at ≤7 days and 10 and 14 weeks produced significantly lower anti-CS GMCs (ratio 0.59; 95% confidence interval, 0.38-0.92). CONCLUSIONS Initiation of RTS,S/AS01E vaccination above 6 weeks of age tended to improve anti-CS antibody responses. Neonatal vaccination was well tolerated but produced a comparatively lower immune response.
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Moris P, Jongert E, van der Most RG. Characterization of T-cell immune responses in clinical trials of the candidate RTS,S malaria vaccine. Hum Vaccin Immunother 2017; 14:17-27. [PMID: 28934066 PMCID: PMC5791571 DOI: 10.1080/21645515.2017.1381809] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The candidate malaria vaccine RTS,S has demonstrated 45.7% efficacy over 18 months against all clinical disease in a phase-III field study of African children. RTS,S targets the circumsporozoite protein (CSP), which is expressed on the Plasmodium sporozoite during the pre-erythrocyte stage of its life-cycle; the stage between mosquito bite and liver infection. Early in the development of RTS,S, it was recognized that CSP-specific cell-mediated immunity (CMI) was required to complement CSP-specific antibody-mediated immunity. In reviewing RTS,S clinical studies, associations between protection and various types of CMI (CSP-specific CD4+ T cells and INF-γ ELISPOTs) have been identified, but not consistently. It is plausible that certain CD4+ T cells support antibody responses or co-operate with other immune-cell types to potentially elicit protection. However, the identities of vaccine correlates of protection, implicating either CSP-specific antibodies or T cells remain elusive, suggesting that RTS,S clinical trials may benefit from additional immunogenicity analyses that can be informed by the results of controlled human malaria infection studies.
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Mahmoudi S, Keshavarz H. Efficacy of phase 3 trial of RTS, S/AS01 malaria vaccine: The need for an alternative development plan. Hum Vaccin Immunother 2017; 13:2098-2101. [PMID: 28272979 DOI: 10.1080/21645515.2017.1295906] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Although vaccines would be the ideal tool for control, prevention, elimination, and eradication of many infectious diseases, developing of parasites vaccines such as malaria vaccine is very complex. The most advanced malaria vaccine candidate RTS,S, a pre-erythrocytic vaccine, has been recommended for licensure by EMEA. The results of this phase III trial suggest that this candidate malaria vaccine has relatively little efficacy, and the vaccine apparently will not meet the goal of malaria eradication by itself. Since there are many vaccine candidates in the pipeline 1 that are being evaluated in vaccine trials, further study on using of alternative parasite targets and vaccination strategies are highly recommended.
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Affiliation(s)
- Shima Mahmoudi
- a Pediatric Infectious Disease Research Center , Tehran University of Medical Science , Tehran , Iran.,b Center for Research of Endemic Parasites of Iran (CREPI) , Tehran University of Medical Sciences , Tehran , Iran
| | - Hossein Keshavarz
- b Center for Research of Endemic Parasites of Iran (CREPI) , Tehran University of Medical Sciences , Tehran , Iran.,c Department of Medical Parasitology and Mycology , School of Public Heath, Tehran, University of Medical Science , Tehran , Iran
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The Plasmodium falciparum Cell-Traversal Protein for Ookinetes and Sporozoites as a Candidate for Preerythrocytic and Transmission-Blocking Vaccines. Infect Immun 2017; 85:IAI.00498-16. [PMID: 27895131 PMCID: PMC5278177 DOI: 10.1128/iai.00498-16] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 11/16/2016] [Indexed: 01/04/2023] Open
Abstract
Recent studies have shown that immune responses against the cell-traversal protein for Plasmodium ookinetes and sporozoites (CelTOS) can inhibit parasite infection. While these studies provide important evidence toward the development of vaccines targeting this protein, it remains unknown whether these responses could engage the Plasmodium falciparum CelTOS in vivo. Using a newly developed rodent malaria chimeric parasite expressing the P. falciparum CelTOS (PfCelTOS), we evaluated the protective effect of in vivo immune responses elicited by vaccination and assessed the neutralizing capacity of monoclonal antibodies specific against PfCelTOS. Mice immunized with recombinant P. falciparum CelTOS in combination with the glucopyranosyl lipid adjuvant-stable emulsion (GLA-SE) or glucopyranosyl lipid adjuvant-liposome-QS21 (GLA-LSQ) adjuvant system significantly inhibited sporozoite hepatocyte infection. Notably, monoclonal antibodies against PfCelTOS strongly inhibited oocyst development of P. falciparum and Plasmodium berghei expressing PfCelTOS in Anopheles gambiae mosquitoes. Taken together, our results demonstrate that anti-CelTOS responses elicited by vaccination or passive immunization can inhibit sporozoite and ookinete infection and impair vector transmission.
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Mahmoudi S, Keshavarz H. Efficacy of Phase 3 Trial of RTS, S/AS01 Malaria Vaccine in infants: a systematic review and meta-analysis. Hum Vaccin Immunother 2017:0. [PMID: 28059665 DOI: 10.1080/21645515.2016.1271686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Although vaccines would be the ideal tool for control, prevention, elimination, and eradication of many infectious diseases, developing of parasites vaccines such as malaria vaccine is very complex. The most advanced malaria vaccine candidate is RTS,S, a pre-erythrocytic vaccine for which pivotal phase III trial design is underway. Few recent malaria vaccine review articles have attempted to outline of all clinical trials that have occurred globally and no meta-analysis was performed on efficacy of Phase 3 Trial of RTS, S/AS01 Malaria vaccine up to now in infants. Therefore, a systematic review and meta-analysis was carried out to review new and existing data on efficacy of Phase 3 Trial of RTS, S/AS01 Malaria Vaccine in infants. The electronic databases searched were Pubmed (1965-present) and Web of Science (1970-present) (Search date: May, 2016). After full-text review of the papers evaluating clinical/severe malaria in several well-designed phase III field efficacy trials, 5 were determined to meet the eligibility criteria for inclusion in the systematic review. Four out of the 5 publications dealing with efficacy of Phase 3 Trial of RTS, S/AS01 malaria vaccine were included in the qualitative analysis. Pooled estimate of vaccine efficacy in clinical and severe malaria in children aged 5-17 mo was 29% (95% CL: 19%-46%) and 39% (95% CI 20%-74%), while this estimate vaccine in clinical and severe malaria in children aged 6-12 mo was 19% (95% CI 14%-24%) and 21 (95% CI 19%-37%), respectively. On the other hand, higher VE was seen in both per- protocol and intention-to-treat population in children aged 5-17 than the children aged 6-12 mo. The results of this meta-analysis suggest that this candidate malaria vaccine has relatively little efficacy, and the vaccine apparently will not meet the goal of malaria eradication by itself.
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Affiliation(s)
- Shima Mahmoudi
- a Pediatric Infectious Disease Research Center, Tehran University of Medical Science , Tehran , Iran
- b Center for Research of Endemic Parasites of Iran (CREPI), Tehran University of Medical Sciences , Tehran , Iran
| | - Hossein Keshavarz
- b Center for Research of Endemic Parasites of Iran (CREPI), Tehran University of Medical Sciences , Tehran , Iran
- c Department of Medical Parasitology and Mycology , School of Public Heath, Tehran University of Medical Science , Tehran , Iran
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Vandoolaeghe P, Schuerman L. The RTS,S/AS01 malaria vaccine in children 5 to 17 months of age at first vaccination. Expert Rev Vaccines 2016; 15:1481-1493. [DOI: 10.1080/14760584.2016.1236689] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Radin K, Clement F, Jongert E, Sterckx YGJ, Ockenhouse C, Regules J, Lemiale F, Leroux-Roels G. A monoclonal antibody-based immunoassay to measure the antibody response against the repeat region of the circumsporozoite protein of Plasmodium falciparum. Malar J 2016; 15:543. [PMID: 27825382 PMCID: PMC5101676 DOI: 10.1186/s12936-016-1596-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 10/31/2016] [Indexed: 12/15/2022] Open
Abstract
Background The malaria vaccine candidate RTS,S/AS01 (GSK Vaccines) induces high IgG concentration against the circumsporozoite protein (CSP) of Plasmodium falciparum. In human vaccine recipients circulating anti-CSP antibody concentrations are associated with protection against infection but appear not to be the correlate of protection. However, in a humanized mouse model of malaria infection prophylactic administration of a human monoclonal antibody (MAL1C), derived from a RTS,S/AS01-immunized volunteer, directed against the CSP repeat region, conveyed full protection in a dose-dependent manner suggesting that antibodies alone are able to prevent P. falciparum infection when present in sufficiently high concentrations. A competition ELISA was developed to measure the presence of MAL1C-like antibodies in polyclonal sera from RTS,S/AS01 vaccine recipients and study their possible contribution to protection against infection. Results MAL1C-like antibodies present in polyclonal vaccine-induced sera were evaluated for their ability to compete with biotinylated monoclonal antibody MAL1C for binding sites on the capture antigen consisting of the recombinant protein encompassing 32 NANP repeats of CSP (R32LR). Serum samples were taken at different time points from participants in two RTS,S/AS01 vaccine studies (NCT01366534 and NCT01857869). Vaccine-induced protection status of the study participants was determined based on the outcome of experimental challenge with infected mosquito bites after vaccination. Optimal conditions were established to reliably detect MAL1C-like antibodies in polyclonal sera. Polyclonal anti-CSP antibodies and MAL1C-like antibody content were measured in 276 serum samples from RTS,S/AS01 vaccine recipients using the standard ELISA and MAL-1C competition ELISA, respectively. A strong correlation was observed between the results from these assays. However, no correlation was found between the results of either assay and protection against infection. Conclusions The competition ELISA to measure MAL1C-like antibodies in polyclonal sera from RTS,S/AS01 vaccine recipients was robust and reliable but did not reveal the elusive correlate of protection. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1596-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kristina Radin
- Center for Vaccinology (CEVAC), Ghent University, Ghent, Belgium
| | - Frederic Clement
- Center for Vaccinology (CEVAC), Ghent University, Ghent, Belgium
| | - Erik Jongert
- GSK Vaccines, Rue de l'Institut 89, B-1330, Rixensart, Belgium
| | - Yann G J Sterckx
- Structural Biology Research Center (SBRC), VIB, Pleinlaan 2, B-1050, Brussels, Belgium.,Research Unit for Cellular and Molecular Immunology (CMIM), VUB, Pleinlaan 2, B-1050, Brussels, Belgium
| | - Christian Ockenhouse
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Washington, DC, 20001, USA
| | - Jason Regules
- Walter Reed Army Institute of Research (WRAIR), 503 Robert Grant Ave., Silver Spring, MD, 20910, USA
| | - Franck Lemiale
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Washington, DC, 20001, USA
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Didierlaurent AM, Laupèze B, Di Pasquale A, Hergli N, Collignon C, Garçon N. Adjuvant system AS01: helping to overcome the challenges of modern vaccines. Expert Rev Vaccines 2016; 16:55-63. [DOI: 10.1080/14760584.2016.1213632] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Regules JA, Cicatelli SB, Bennett JW, Paolino KM, Twomey PS, Moon JE, Kathcart AK, Hauns KD, Komisar JL, Qabar AN, Davidson SA, Dutta S, Griffith ME, Magee CD, Wojnarski M, Livezey JR, Kress AT, Waterman PE, Jongert E, Wille-Reece U, Volkmuth W, Emerling D, Robinson WH, Lievens M, Morelle D, Lee CK, Yassin-Rajkumar B, Weltzin R, Cohen J, Paris RM, Waters NC, Birkett AJ, Kaslow DC, Ballou WR, Ockenhouse CF, Vekemans J. Fractional Third and Fourth Dose of RTS,S/AS01 Malaria Candidate Vaccine: A Phase 2a Controlled Human Malaria Parasite Infection and Immunogenicity Study. J Infect Dis 2016; 214:762-71. [PMID: 27296848 DOI: 10.1093/infdis/jiw237] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 05/26/2016] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Three full doses of RTS,S/AS01 malaria vaccine provides partial protection against controlled human malaria parasite infection (CHMI) and natural exposure. Immunization regimens, including a delayed fractional third dose, were assessed for potential increased protection against malaria and immunologic responses. METHODS In a phase 2a, controlled, open-label, study of healthy malaria-naive adults, 16 subjects vaccinated with a 0-, 1-, and 2-month full-dose regimen (012M) and 30 subjects who received a 0-, 1-, and 7-month regimen, including a fractional third dose (Fx017M), underwent CHMI 3 weeks after the last dose. Plasmablast heavy and light chain immunoglobulin messenger RNA sequencing and antibody avidity were evaluated. Protection against repeat CHMI was evaluated after 8 months. RESULTS A total of 26 of 30 subjects in the Fx017M group (vaccine efficacy [VE], 86.7% [95% confidence interval [CI], 66.8%-94.6%]; P < .0001) and 10 of 16 in the 012M group (VE, 62.5% [95% CI, 29.4%-80.1%]; P = .0009) were protected against infection, and protection differed between schedules (P = .040, by the log rank test). The fractional dose boosting increased antibody somatic hypermutation and avidity and sustained high protection upon rechallenge. DISCUSSIONS A delayed third fractional vaccine dose improved immunogenicity and protection against infection. Optimization of the RTS,S/AS01 immunization regimen may lead to improved approaches against malaria. CLINICAL TRIALS REGISTRATION NCT01857869.
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Affiliation(s)
- Jason A Regules
- Malaria Vaccine Branch Military Malaria Research Program Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | | | - Jason W Bennett
- Malaria Vaccine Branch Military Malaria Research Program Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | | | - Patrick S Twomey
- Experimental Therapeutics Branch Military Malaria Research Program
| | - James E Moon
- Malaria Vaccine Branch Military Malaria Research Program
| | | | - Kevin D Hauns
- Malaria Vaccine Branch Military Malaria Research Program
| | - Jack L Komisar
- Malaria Vaccine Branch Military Malaria Research Program
| | - Aziz N Qabar
- Malaria Vaccine Branch Military Malaria Research Program
| | - Silas A Davidson
- Entomology Branch, Walter Reed Army Institute of Research, Silver Spring
| | - Sheetij Dutta
- Malaria Vaccine Branch Military Malaria Research Program
| | - Matthew E Griffith
- Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Charles D Magee
- Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | | | | | - Adrian T Kress
- Experimental Therapeutics Branch Military Malaria Research Program
| | | | | | | | | | | | | | | | | | - Cynthia K Lee
- PATH Malaria Vaccine Initiative, Seattle, Washington
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Dudley HJ, Goenka A, Orellana CJ, Martonosi SE. Multi-year optimization of malaria intervention: a mathematical model. Malar J 2016; 15:133. [PMID: 26931111 PMCID: PMC4774123 DOI: 10.1186/s12936-016-1182-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 02/18/2016] [Indexed: 11/18/2022] Open
Abstract
Background Malaria is a mosquito-borne, lethal disease that affects millions and kills hundreds of thousands of people each year, mostly children. There is an increasing need for models of malaria control. In this paper, a model is developed for allocating malaria interventions across geographic regions and time, subject to budget constraints, with the aim of minimizing the number of person-days of malaria infection. Methods The model considers a range of several conditions: climatic characteristics, treatment efficacy, distribution costs, and treatment coverage. An expanded susceptible-infected-recovered compartment model for the disease dynamics is coupled with an integer linear programming model for selecting the disease interventions. The model produces an intervention plan for all regions, identifying which combination of interventions, with which level of coverage, to use in each region and year in a 5-year planning horizon. Results Simulations using the model yield high-level, qualitative insights on optimal intervention policies: The optimal intervention policy is different when considering a 5-year time horizon than when considering only a single year, due to the effects that interventions have on the disease transmission dynamics. The vaccine intervention is rarely selected, except if its assumed cost is significantly lower than that predicted in the literature. Increasing the available budget causes the number of person-days of malaria infection to decrease linearly up to a point, after which the benefit of increased budget starts to taper. The optimal policy is highly dependent on assumptions about mosquito density, selecting different interventions for wet climates with high density than for dry climates with low density, and the interventions are found to be less effective at controlling malaria in the wet climates when attainable intervention coverage is 60 % or lower. However, when intervention coverage of 80 % is attainable, then malaria prevalence drops quickly in all geographic regions, even when factoring in the greater expense of the higher coverage against a constant budget. Conclusions The model provides a qualitative decision-making tool to weigh alternatives and guide malaria eradication efforts. A one-size-fits-all campaign is found not to be cost-effective; it is better to consider geographic variations and changes in malaria transmission over time when determining intervention strategies.
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Affiliation(s)
- Harry J Dudley
- University of Colorado Boulder, 526 UCB, University of Colorado, Boulder, CO, 80309-0526, USA.
| | - Abhishek Goenka
- Harvey Mudd College, 301 Platt Blvd, Claremont, CA, 91711, USA.
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Ahouidi AD, Amambua-Ngwa A, Awandare GA, Bei AK, Conway DJ, Diakite M, Duraisingh MT, Rayner JC, Zenonos ZA. Malaria Vaccine Development: Focusing Field Erythrocyte Invasion Studies on Phenotypic Diversity: The West African Merozoite Invasion Network (WAMIN). Trends Parasitol 2015; 32:274-283. [PMID: 26725306 DOI: 10.1016/j.pt.2015.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 12/14/2022]
Abstract
Erythrocyte invasion by Plasmodium falciparum merozoites is an essential step for parasite survival and proliferation. Invasion is mediated by multiple ligands, which could be promising vaccine targets. The usage and sequence of these ligands differs between parasites, yet most studies of them have been carried out in only a few laboratory-adapted lines. To understand the true extent of natural variation in invasion phenotypes and prioritize vaccine candidates on a relevant evidence base, we need to develop and apply standardized assays to large numbers of field isolates. The West African Merozoite Invasion Network (WAMIN) has been formed to meet these goals, expand training in Plasmodium phenotyping, and perform large-scale field phenotyping studies in order to prioritize blood stage vaccine candidates.
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Affiliation(s)
| | - Ambroise D Ahouidi
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | | | - Gordon A Awandare
- West African Center for Cell Biology of Infectious Pathogens and Department of Biochemistry, Cell, and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Amy K Bei
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal; Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - David J Conway
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Mahamadou Diakite
- Faculty of Medicine, Pharmacy, and Odontostomatology, University of Bamako, Bamako, Mali
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Julian C Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Cambridge CB10 1SA, UK.
| | - Zenon A Zenonos
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Cambridge CB10 1SA, UK
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Abstract
In 2013 there were an estimated 584,000 deaths and 198 million clinical illnesses due to malaria, the majority in sub-Saharan Africa. Vaccines would be the ideal addition to the existing armamentarium of anti-malaria tools. However, malaria is caused by parasites, and parasites are much more complex in terms of their biology than the viruses and bacteria for which we have vaccines, passing through multiple stages of development in the human host, each stage expressing hundreds of unique antigens. This complexity makes it more difficult to develop a vaccine for parasites than for viruses and bacteria, since an immune response targeting one stage may not offer protection against a later stage, because different antigens are the targets of protective immunity at different stages. Furthermore, depending on the life cycle stage and whether the parasite is extra- or intra-cellular, antibody and/or cellular immune responses provide protection. It is thus not surprising that there is no vaccine on the market for prevention of malaria, or any human parasitic infection. In fact, no vaccine for any disease with this breadth of targets and immune responses exists. In this limited review, we focus on four approaches to malaria vaccines, (1) a recombinant protein with adjuvant vaccine aimed at Plasmodium falciparum (Pf) pre-erythrocytic stages of the parasite cycle (RTS,S/AS01), (2) whole sporozoite vaccines aimed at Pf pre-erythrocytic stages (PfSPZ Vaccine and PfSPZ-CVac), (3) prime boost vaccines that include recombinant DNA, viruses and bacteria, and protein with adjuvant aimed primarily at Pf pre-erythrocytic, but also asexual erythrocytic stages, and (4) recombinant protein with adjuvant vaccines aimed at Pf and Plasmodium vivax sexual erythrocytic and mosquito stages. We recognize that we are not covering all approaches to malaria vaccine development, or most of the critically important work on development of vaccines against P. vivax, the second most important cause of malaria. Progress during the last few years has been significant, and a first generation malaria candidate vaccine, RTS,S/AS01, is under review by the European Medicines Agency (EMA) for its quality, safety and efficacy under article 58, which allows the EMA to give a scientific opinion about products intended exclusively for markets outside of the European Union. However, much work is in progress to optimize malaria vaccines in regard to magnitude and durability of protective efficacy and the financing and practicality of delivery. Thus, we are hopeful that anti-malaria vaccines will soon be important tools in the battle against malaria.
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