1
|
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.
Collapse
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
| |
Collapse
|
2
|
Nyandele JP, Kibondo UA, Issa F, Van Geertruyden JP, Warimwe G, Jongo S, Abdulla S, Olotu A. Pre-vaccination monocyte-to-lymphocyte ratio as a biomarker for the efficacy of malaria candidate vaccines: A subgroup analysis of pooled clinical trial data. PLoS One 2023; 18:e0291244. [PMID: 37708143 PMCID: PMC10501550 DOI: 10.1371/journal.pone.0291244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/24/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND Pre-vaccination monocyte-to-lymphocyte ratio was previously suggested as a marker for malaria vaccine effectiveness. We investigated the potential of this cell ratio as a marker for malaria vaccine efficacy and effectiveness. Effectiveness was investigated by using clinical malaria endpoint, and efficacy was investigated by using surrogate endpoints of Plasmodium falciparum prepatent period, parasite density, and multiplication rates in a controlled human malaria infection trial (CHMI). METHODS We evaluated the correlation between monocyte-to-lymphocyte ratio and RTS,S vaccine effectiveness using Cox regression modeling with clinical malaria as the primary endpoint. Of the 1704 participants in the RTS,S field trial, data on monocyte-to-lymphocyte ratio was available for 842 participants, of whom our analyses were restricted. We further used Spearman Correlations and Cox regression modeling to evaluate the correlation between monocyte-to-lymphocyte ratio and Whole Sporozoite malaria vaccine efficacy using the surrogate endpoints. Of the 97 participants in the controlled human malaria infection vaccine trials, hematology and parasitology information were available for 82 participants, of whom our analyses were restricted. RESULTS The unadjusted efficacy of RTS,S malaria vaccine was 54% (95% CI: 37%-66%, p <0.001). No correlation was observed between monocyte-to-lymphocyte ratio and RTS,S vaccine efficacy (Hazard Rate (HR):0.90, 95%CI:0.45-1.80; p = 0.77). The unadjusted efficacy of Whole Sporozoite malaria vaccine in the appended dataset was 17.6% (95%CI:10%-28.5%, p<0.001). No association between monocyte-to-lymphocyte ratio and the Whole Sporozoite malaria vaccine was found against either the prepatent period (HR = 1.16; 95%CI:0.51-2.62, p = 0.72), parasite density (rho = 0.004, p = 0.97) or multiplication rates (rho = 0.031, p = 0.80). CONCLUSION Monocyte-to-lymphocyte ratio alone may not be an adequate marker for malaria vaccine efficacy. Further investigations on immune correlates and underlying mechanisms of immune protection against malaria could provide a clearer explanation of the differences between those protected in comparison with those not protected against malaria by vaccination.
Collapse
Affiliation(s)
- Jane Paula Nyandele
- Global Health Institute, University of Antwerp, Antwerp, Belgium
- Ifakara Health Institute, Bagamoyo Clinical Trial Unit, Bagamoyo, Tanzania
| | - Ummi Abdul Kibondo
- Ifakara Health Institute, Bagamoyo Clinical Trial Unit, Bagamoyo, Tanzania
| | - Fatuma Issa
- Ifakara Health Institute, Bagamoyo Clinical Trial Unit, Bagamoyo, Tanzania
| | | | | | - Said Jongo
- Ifakara Health Institute, Bagamoyo Clinical Trial Unit, Bagamoyo, Tanzania
| | - Salim Abdulla
- Ifakara Health Institute, Bagamoyo Clinical Trial Unit, Bagamoyo, Tanzania
| | - Ally Olotu
- Ifakara Health Institute, Bagamoyo Clinical Trial Unit, Bagamoyo, Tanzania
| |
Collapse
|
3
|
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: 17] [Impact Index Per Article: 8.5] [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]
|
4
|
Schneider CG, Fey J, Zou X, Gerbasi V, Savransky T, Batt C, Bergmann-Leitner E, Angov E. Norovirus-VLPs expressing pre-erythrocytic malaria antigens induce functional immunity against sporozoite infection. Vaccine 2022; 40:4270-4280. [PMID: 35697572 DOI: 10.1016/j.vaccine.2022.05.076] [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: 03/22/2022] [Revised: 04/27/2022] [Accepted: 05/24/2022] [Indexed: 10/18/2022]
Abstract
Despite the development of prophylactic anti-malarial drugs and practices to prevent infection, malaria remains a health concern. Preclinical testing of novel malaria vaccine strategies achieved through rational antigen selection and novel particle-based delivery platforms is yielding encouraging results. One such platform, self-assembling virus-like particles (VLP) is safer than attenuated live viruses, and has been approved as a vaccination tool by the FDA. We explore the use of Norovirus sub-viral particles lacking the natural shell (S) domain forming the interior shell but that retain the protruding (P) structures of the native virus as a vaccine vector. Epitope selection and their surface display has the potential to focus antigen specific immune responses to crucial epitopes. Recombinant P-particles displaying epitopes from two malaria antigens, Plasmodium falciparum (Pf) CelTOS and Plasmodium falciparum (Pf) CSP, were evaluated for immunogenicity and their ability to confer protection in a murine challenge model. Immune responses induced in mice resulted either in sterile protection (displaying PfCelTOS epitopes) or in antibodies with functional activity against sporozoites (displaying PfCSP epitopes) in an in vitro liver-stage development assay (ILSDA). These results are encouraging and support further evaluation of this platform as a vaccine delivery system.
Collapse
Affiliation(s)
- Cosette G Schneider
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA; Oak Ridge Institute for Science and Education, Oak Ridge, TN 37831, USA.
| | - Julien Fey
- Agave BioSystems, Ithaca, NY 14850, USA.
| | - Xiaoyan Zou
- Naval Medical Research Center, Silver Spring, MD 20910, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20817, USA
| | - Vince Gerbasi
- Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Tatyana Savransky
- Entomology Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA; General Dynamics Information Technology, Falls Church, VA 22042, USA.
| | - Carl Batt
- College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
| | - Elke Bergmann-Leitner
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
| | - Evelina Angov
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
| |
Collapse
|
5
|
Gyaase S, Asante KP, Adeniji E, Boahen O, Cairns M, Owusu-Agyei S. Potential effect modification of RTS,S/AS01 malaria vaccine efficacy by household socio-economic status. BMC Public Health 2021; 21:240. [PMID: 33509156 PMCID: PMC7845116 DOI: 10.1186/s12889-021-10294-x] [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: 10/01/2020] [Accepted: 01/20/2021] [Indexed: 01/17/2023] Open
Abstract
Background In the phase III RTS,S /AS01 trial, significant heterogeneity in efficacy of the vaccine across study sites was seen. Question on whether variations in socio - economic status (SES) of participant contributed to the heterogeinity of the vaccine efficacy (VE) remains unknown. Methods Data from the Phase III RTS,S /AS01 trial in children aged 5–17 months in Kintampo were re-analysed. SES of each child was derived from the Kintampo Health and Demographic Surveillance System, using principal component analysis of household assets. Extended Cox regression was used to estimate the interaction between RTS,S/AS01 VE and household SES. Results Protective efficacy of the RTS,S/AS0 vaccine significantly varied by participant’s household SES, thus increase in household SES was associated with an increase in protective efficacy (P-value = 0.0041). Effect modification persisted after adjusting for age at first vaccination, gender, distance from community to the health facility, child’s haemoglobin level, household size, place of residence and mothers’ educational level. Conclusion Household SES may be a proxy for malaria transmission intensity. The study showed a significant modification of the RTS,S/AS01 malaria vaccine efficacy by the different levels of child’s household socio - economic status. Trial registration Efficacy of GSK Biologicals’ candidate malaria vaccine (25049) against malaria disease in infants and children in Africa. NCT00866619 prospectively registered on 20 March 2009.
Collapse
Affiliation(s)
- Stephaney Gyaase
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Kwaku Poku Asante
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana.,Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Elisha Adeniji
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Owusu Boahen
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Matthew Cairns
- Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Seth Owusu-Agyei
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana. .,Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK. .,Institute of Health Research, University of Health and Allied Sciences, Ho, Volta, Ghana.
| |
Collapse
|
6
|
Roman FP, Coccia M, Schuerman L. Commentary in reply to a publication on Plasmodium falciparum pre-erythrocytic stage vaccine development. Malar J 2020; 19:261. [PMID: 32690097 PMCID: PMC7370254 DOI: 10.1186/s12936-020-03334-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/13/2020] [Indexed: 11/10/2022] Open
Abstract
We have read the publication of Molina-Franky and colleagues on Plasmodium falciparum pre-erythrocytic stage vaccine development (Malaria Journal, 2020;19:56). The commentary revises some of their statements on the RTS,S/AS01 vaccine that are considered either imprecise or incorrect.
Collapse
|
7
|
Bell GJ, Loop M, Topazian HM, Hudgens M, Mvalo T, Juliano JJ, Kamthunzi P, Tegha G, Mofolo I, Hoffman I, Bailey JA, Emch M. Case reduction and cost-effectiveness of the RTS,S/AS01 malaria vaccine alongside bed nets in Lilongwe, Malawi. Vaccine 2020; 38:4079-4087. [PMID: 32362527 DOI: 10.1016/j.vaccine.2020.04.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 04/10/2020] [Accepted: 04/13/2020] [Indexed: 01/22/2023]
Abstract
BACKGROUND RTS,S/AS01, the most advanced vaccine against malaria, is now undergoing pilot implementation in Malawi, Ghana, and Kenya where an estimated 360,000 children will be vaccinated each year. In this study we evaluate RTS,S/AS01 alongside bed net use and estimate cost-effectiveness. METHODS RTS,S/AS01 phase III trial and bed net prevalence data were used to determine the effect of vaccination in the urban/periurban and rural areas of Lilongwe, Malawi. Cost data were used to calculate the cost-effectiveness of various interventions over three years. FINDINGS Since bed nets reduce malaria incidence and homogeneous vaccine efficacy was assumed, participants without bed nets received greater relative benefit from vaccination with RTS,S/AS01 than participants with bed nets. Similarly, since malaria incidence in rural Lilongwe is higher than in urban Lilongwe, the impact and cost-effectiveness of vaccine interventions is increased in rural areas. In rural Lilongwe, we estimated that vaccinating one child without a bed net would prevent 2·59 (1·62 to 3·38) cases of malaria over three years, corresponding to a cost of $10·08 (7·71 to 16·13) per case averted. Alternatively, vaccinating one child with a bed net would prevent 1·59 (0·87 to 2·57) cases, corresponding to $16·43 (10·16 to 30·06) per case averted. Providing RTS,S/AS01 to 30,000 children in rural Lilongwe was estimated to cost $782,400 and to prevent 58,611 (35,778 to 82,932) cases of malaria over a three-year period. Joint interventions providing both vaccination and bed nets (to those without them) were estimated to prevent additional cases of malaria and to be similarly cost-effective, compared to vaccine-only interventions. INTERPRETATION To maximize malaria prevention, vaccination and bed net distribution programs could be integrated. FUNDING Impacts of Environment, Host Genetics and Antigen Diversity on Malaria Vaccine Efficacy (1R01AI137410-01).
Collapse
Affiliation(s)
- Griffin J Bell
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Matthew Loop
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Hillary M Topazian
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Michael Hudgens
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Tisungane Mvalo
- University of North Carolina, Chapel Hill, NC 27599, USA; University of North Carolina Project, Lilongwe, Malawi.
| | - Jonathan J Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Portia Kamthunzi
- University of North Carolina, Chapel Hill, NC 27599, USA; University of North Carolina Project, Lilongwe, Malawi.
| | - Gerald Tegha
- University of North Carolina Project, Lilongwe, Malawi.
| | - Innocent Mofolo
- University of North Carolina, Chapel Hill, NC 27599, USA; University of North Carolina Project, Lilongwe, Malawi.
| | - Irving Hoffman
- University of North Carolina, Chapel Hill, NC 27599, USA; University of North Carolina Project, Lilongwe, Malawi.
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI 02903, USA
| | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA.
| |
Collapse
|
8
|
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.
Collapse
|
9
|
Vijayan V, Mohapatra A, Uthaman S, Park IK. Recent Advances in Nanovaccines Using Biomimetic Immunomodulatory Materials. Pharmaceutics 2019; 11:E534. [PMID: 31615112 PMCID: PMC6835828 DOI: 10.3390/pharmaceutics11100534] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 12/28/2022] Open
Abstract
The development of vaccines plays a vital role in the effective control of several fatal diseases. However, effective prophylactic and therapeutic vaccines have yet to be developed for completely curing deadly diseases, such as cancer, malaria, HIV, and serious microbial infections. Thus, suitable vaccine candidates need to be designed to elicit appropriate immune responses. Nanotechnology has been found to play a unique role in the design of vaccines, providing them with enhanced specificity and potency. Nano-scaled materials, such as virus-like particles, liposomes, polymeric nanoparticles (NPs), and protein NPs, have received considerable attention over the past decade as potential carriers for the delivery of vaccine antigens and adjuvants, due to their beneficial advantages, like improved antigen stability, targeted delivery, and long-time release, for which antigens/adjuvants are either encapsulated within, or decorated on, the NP surface. Flexibility in the design of nanomedicine allows for the programming of immune responses, thereby addressing the many challenges encountered in vaccine development. Biomimetic NPs have emerged as innovative natural mimicking biosystems that can be used for a wide range of biomedical applications. In this review, we discuss the recent advances in biomimetic nanovaccines, and their use in anti-bacterial therapy, anti-HIV therapy, anti-malarial therapy, anti-melittin therapy, and anti-tumor immunity.
Collapse
Affiliation(s)
- Veena Vijayan
- Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju 58128, Korea.
| | - Adityanarayan Mohapatra
- Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju 58128, Korea.
| | - Saji Uthaman
- Department of Polymer Science and Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.
| | - In-Kyu Park
- Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju 58128, Korea.
| |
Collapse
|
10
|
Tinto H, Otieno W, Gesase S, Sorgho H, Otieno L, Liheluka E, Valéa I, Sing'oei V, Malabeja A, Valia D, Wangwe A, Gvozdenovic E, Guerra Mendoza Y, Jongert E, Lievens M, Roman F, Schuerman L, Lusingu J. Long-term incidence of severe malaria following RTS,S/AS01 vaccination in children and infants in Africa: an open-label 3-year extension study of a phase 3 randomised controlled trial. THE LANCET. INFECTIOUS DISEASES 2019; 19:821-832. [PMID: 31300331 DOI: 10.1016/s1473-3099(19)30300-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 03/01/2019] [Accepted: 04/16/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Results from a previous phase 3 study showed efficacy of the RTS,S/AS01 vaccine against severe and clinical malaria in children (in 11 sites in Africa) during a 3-4-year follow-up. We aimed to investigate malaria incidence up to 7 years postvaccination in three of the sites of the initial study. METHODS In the initial phase 3 study, infants aged 6-12 weeks and children aged 5-17 months were randomly assigned (1:1:1) to receive four RTS,S/AS01 doses (four-dose group), three RTS,S/AS01 doses and a comparator dose (three-dose group), or four comparator doses (control group). In this open-label extension study in Korogwe (Tanzania), Kombewa (Kenya), and Nanoro (Burkina Faso), we assessed severe malaria incidences as the primary outcome for 3 additional years (January, 2014, to December, 2016), up to 6 years (younger children) or 7 years (older children) postprimary vaccination in the modified intention-to-treat population (ie, participants who received at least one dose of the study vaccine). As secondary outcomes, we evaluated clinical malaria incidences and serious adverse events. This trial is registered with ClinicalTrials.gov, number NCT02207816. FINDINGS We enrolled 1739 older children (aged 5-7 years) and 1345 younger children (aged 3-5 years). During the 3-year extension, 66 severe malaria cases were reported, resulting in severe malaria incidence of 0·004 cases per person-years at risk (PPY; 95% CI 0-0·033) in the four-dose group, 0·007 PPY (0·001-0·052) in the three-dose group, and 0·009 PPY (0·001-0·066) in the control group in the older children category and a vaccine efficacy against severe malaria that did not contribute significantly to the overall efficacy (four-dose group 53·7% [95% CI -13·7 to 81·1], p=0·093; three-dose group 23·3% [-67·1 to 64·8], p=0·50). In younger children, severe malaria incidences were 0·007 PPY (0·001-0·058) in the four-dose group, 0·007 PPY (0·001-0·054) in the three-dose group, and 0·011 PPY (0·001-0·083) in the control group. Vaccine efficacy against severe malaria also did not contribute significantly to the overall efficacy (four-dose group 32·1% [-53·1 to 69·9], p=0·35; three-dose group 37·6% [-44·4 to 73·0], p=0·27). Malaria transmission was still occurring as evidenced by an incidence of clinical malaria ranging from 0·165 PPY to 3·124 PPY across all study groups and sites. In older children, clinical malaria incidence was 1·079 PPY (95% CI 0·152-7·662) in the four-dose group, 1·108 PPY (0·156-7·868) in the three-dose group, and 1·016 PPY (0·14-7·213) in the control group. In younger children, malaria incidence was 1·632 PPY (0·23-11·59), 1·563 PPY (0·22-11·104), and 1·686 PPY (0·237-11·974), respectively. In the older age category in Nanoro, clinical malaria incidence was higher in the four-dose (2·444 PPY; p=0·011) and three-dose (2·411 PPY; p=0·034) groups compared with the control group (1·998 PPY). Three cerebral malaria episodes and five meningitis cases, but no vaccine-related severe adverse events, were reported. INTERPRETATION Overall, severe malaria incidence was low in all groups, with no evidence of rebound in RTS,S/AS01 recipients, despite an increased incidence of clinical malaria in older children who received RTS,S/AS01 compared with the comparator group in Nanoro. No safety signal was identified. FUNDING GlaxoSmithKline Biologicals SA.
Collapse
Affiliation(s)
- Halidou Tinto
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Walter Otieno
- Walter Reed Project, Kenya Medical Research Institute, US Medical Research Directorate, Kombewa, Kenya
| | - Samwel Gesase
- National Institute for Medical Research, Korogwe, Tanzania
| | - Hermann Sorgho
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Lucas Otieno
- Walter Reed Project, Kenya Medical Research Institute, US Medical Research Directorate, Kombewa, Kenya
| | - Edwin Liheluka
- National Institute for Medical Research, Korogwe, Tanzania
| | - Innocent Valéa
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Valentine Sing'oei
- Walter Reed Project, Kenya Medical Research Institute, US Medical Research Directorate, Kombewa, Kenya
| | | | - Daniel Valia
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Anne Wangwe
- Walter Reed Project, Kenya Medical Research Institute, US Medical Research Directorate, Kombewa, Kenya
| | | | | | | | - Marc Lievens
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso.
| | | | | | - John Lusingu
- National Institute for Medical Research, Korogwe, Tanzania; Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
11
|
Mehrizi AA, Ameri Torzani M, Zakeri S, Jafary Zadeh A, Babaeekhou L. Th1 immune response to Plasmodium falciparum recombinant thrombospondin-related adhesive protein (TRAP) antigen is enhanced by TLR3-specific adjuvant, poly(I:C) in BALB/c mice. Parasite Immunol 2019; 40:e12538. [PMID: 29799636 DOI: 10.1111/pim.12538] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/21/2018] [Indexed: 12/12/2022]
Abstract
Sporozoite-based malaria vaccines have provided a gold standard for malaria vaccine development, and thrombospondin-related adhesive protein (TRAP) serves as the main vaccine candidate antigen on sporozoites. As recombinant malaria vaccine candidate antigens are poorly immunogenic, additional appropriate immunostimulants, such as an efficient adjuvant, are highly essential to modulate Th1-cell predominance and also to induce a protective and long-lived immune response. In this study, polyinosinic:polycytidylic acid [poly(I:C)], the ligand of TLR3, was considered as the potential adjuvant for vaccines targeting stronger Th1-based immune responses. For this purpose, BALB/c mice were immunized with rPfTRAP delivered in putative poly(I:C) adjuvant, and humoural and cellular immune responses were determined in different immunized mouse groups. Delivery of rPfTRAP with poly(I:C) induced high levels and titres of persisted and also high-avidity anti-rPfTRAP IgG antibodies comparable to complete Freund's adjuvant (CFA)/incomplete Freund's adjuvant (IFA) adjuvant after the second boost. In addition, rPfTRAP formulated with poly(I:C) elicited a higher ratio of IFN-γ/IL-5, IgG2a/IgG1, and IgG2b/IgG1 than with CFA/IFA, indicating that poly(I:C) supports the induction of a stronger Th1-based immune response. This is a first time study which reveals the potential of rPfTRAP delivery in poly(I:C) to increase the level, avidity and durability of both anti-PfTRAP cytophilic antibodies and Th1 cytokines.
Collapse
Affiliation(s)
- A A Mehrizi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - M Ameri Torzani
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran.,Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran
| | - S Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - A Jafary Zadeh
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - L Babaeekhou
- Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran
| |
Collapse
|
12
|
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.
Collapse
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
| | | |
Collapse
|
13
|
Brod F, Miura K, Taylor I, Li Y, Marini A, Salman AM, Spencer AJ, Long CA, Biswas S. Combination of RTS,S and Pfs25-IMX313 Induces a Functional Antibody Response Against Malaria Infection and Transmission in Mice. Front Immunol 2018; 9:2780. [PMID: 30564231 PMCID: PMC6288435 DOI: 10.3389/fimmu.2018.02780] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/12/2018] [Indexed: 12/18/2022] Open
Abstract
The last two decades saw a dramatic reduction in malaria incidence rates, but this decrease has been stalling recently, indicating control measures are starting to fail. An effective vaccine, particularly one with a marked effect on disease transmission, would undoubtedly be an invaluable tool for efforts to control and eliminate malaria. RTS,S/AS01, the most advanced malaria vaccine to date, targets the parasite before it invades the liver and has the potential to prevent malaria disease as well as transmission by preventing blood stage infection and therefore gametocytogenesis. Unfortunately efficacy in a phase III clinical trial was limited and it is widely believed that a malaria vaccine needed to contain multiple antigens from different life-cycle stages to have a realistic chance of success. A recent study in mice has shown that partially efficacious interventions targeting the pre-erythrocytic and the sexual lifecycle stage synergise in eliminating malaria from a population over multiple generations. Hence, the combination of RTS,S/AS01 with a transmission blocking vaccine (TBV) is highly appealing as a pragmatic and powerful way to increase vaccine efficacy. Here we demonstrate that combining Pfs25-IMX313, one of the TBV candidates currently in clinical development, with RTS,S/AS01 readily induces a functional immune response against both antigens in outbred CD1 mice. Formulation of Pfs25-IMX313 in AS01 significantly increased antibody titres when compared to formulation in Alhydrogel, resulting in improved transmission reducing activity in standard membrane feeding assays (SMFA). Upon co-formulation of Pfs25-IMX313 with RTS,S/AS01, the immunogenicity of both vaccines was maintained, and functional assessment of the induced antibody response by SMFA and inhibition of sporozoite invasion assay (ISI) showed no reduction in biological activity against parasites of both lifecycle stages. Should this findings be translatable to human vaccination this could greatly aid efforts to eliminate and eventually eradicate malaria.
Collapse
Affiliation(s)
- Florian Brod
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, United States
| | - Iona Taylor
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Yuanyuan Li
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Arianna Marini
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Ahmed M Salman
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, United States
| | - Sumi Biswas
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
14
|
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.
Collapse
|
15
|
Ward CL, Shaw D, Anane-Sarpong E, Sankoh O, Tanner M, Elger B. The Ethics of End-of-Trial Obligations in a Pediatric Malaria Vaccine Trial: The Perspectives of Stakeholders From Ghana and Tanzania. J Empir Res Hum Res Ethics 2018; 13:258-269. [PMID: 29756531 DOI: 10.1177/1556264618771809] [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: 11/16/2022]
Abstract
This study explores stakeholder experiences and perspectives on end-of-trial obligations at the close of a phase II/III Pediatric Malaria Vaccine Trial (PMVT) [GSK/PATH-MVI RTS, S) (NCT00866619]. We conducted 52 key informant interviews with major stakeholders of an international multicentre PMVT in Ghana and Tanzania. The responses fell into four main themes: (a) Communicating End-of-Trial, (b) Maintaining Health Care Services, (c) Dissemination of Results, and (d) Post-Trial Access. Interviewee responses shared important practical experiences and insights that complement current thinking in the literature on research ethics guidance: (a) accompany end-of-trial communication with information on personal and family health care responsibilities, (b) establish public health indicators to measure the impact of research on a health care system,
Collapse
|
16
|
Coelho CH, Doritchamou JYA, Zaidi I, Duffy PE. Advances in malaria vaccine development: report from the 2017 malaria vaccine symposium. NPJ Vaccines 2017. [PMID: 29522056 PMCID: PMC5709382 DOI: 10.1038/s41541-017-0035-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Malaria Vaccine Symposium occurred at Johns Hopkins University in Baltimore, MD, USA on April 25th, 2017, coinciding with World Malaria Day and the WHO announcement that the RTS,S malaria vaccine would begin pilot implementation programs in Ghana, Kenya, and Malawi in 2018. Scientists from several disciplines reported progress on an array of malaria vaccine concepts and product candidates, including pre-erythrocytic vaccines that prevent infection, blood-stage vaccines that limit infection and disease, and transmission-blocking vaccines that interrupt the spread of infection. Other speakers highlighted the immunological and genetic considerations that must be addressed by vaccinologists to yield the most efficacious vaccines. Here, we highlight the advances in malaria vaccinology that were reported at the symposium.
Collapse
Affiliation(s)
- Camila Henriques Coelho
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD USA
| | - Justin Yai Alamou Doritchamou
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD USA
| | - Irfan Zaidi
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD USA
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD USA
| |
Collapse
|
17
|
Drakeley C, Abdulla S, Agnandji ST, Fernandes JF, Kremsner P, Lell B, Mewono L, Bache BE, Mihayo MG, Juma O, Tanner M, Tahita MC, Tinto H, Diallo S, Lompo P, D'Alessandro U, Ogutu B, Otieno L, Otieno S, Otieno W, Oyieko J, Asante KP, Dery DBE, Adjei G, Adeniji E, Atibilla D, Owusu-Agyei S, Greenwood B, Gesase S, Lusingu J, Mahende C, Mongi R, Segeja M, Adjei S, Agbenyega T, Agyekum A, Ansong D, Bawa JT, Boateng HO, Dandalo L, Escamilla V, Hoffman I, Maenje P, Martinson F, Carter T, Leboulleux D, Kaslow DC, Usuf E, Pirçon JY, Bahmanyar ER. Longitudinal estimation of Plasmodium falciparum prevalence in relation to malaria prevention measures in six sub-Saharan African countries. Malar J 2017; 16:433. [PMID: 29078773 PMCID: PMC5658967 DOI: 10.1186/s12936-017-2078-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 10/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum prevalence (PfPR) is a widely used metric for assessing malaria transmission intensity. This study was carried out concurrently with the RTS,S/AS01 candidate malaria vaccine Phase III trial and estimated PfPR over ≤ 4 standardized cross-sectional surveys. METHODS This epidemiology study (NCT01190202) was conducted in 8 sites from 6 countries (Burkina Faso, Gabon, Ghana, Kenya, Malawi, and Tanzania), between March 2011 and December 2013. Participants were enrolled in a 2:1:1 ratio according to age category: 6 months-4 years, 5-19 years, and ≥ 20 years, respectively, per year and per centre. All sites carried out surveys 1-3 while survey 4 was conducted only in 3 sites. Surveys were usually performed during the peak malaria parasite transmission season, in one home visit, when medical history and malaria risk factors/prevention measures were collected, and a blood sample taken for rapid diagnostic test, microscopy, and haemoglobin measurement. PfPR was estimated by site and age category. RESULTS Overall, 6401 (survey 1), 6411 (survey 2), 6400 (survey 3), and 2399 (survey 4) individuals were included in the analyses. In the 6 months-4 years age group, the lowest prevalence (assessed using microscopy) was observed in 2 Tanzanian centres (4.6% for Korogwe and 9.95% for Bagamoyo) and Lambaréné, Gabon (6.0%), while the highest PfPR was recorded for Nanoro, Burkina Faso (52.5%). PfPR significantly decreased over the 3 years in Agogo (Ghana), Kombewa (Kenya), Lilongwe (Malawi), and Bagamoyo (Tanzania), and a trend for increased PfPR was observed over the 4 surveys for Kintampo, Ghana. Over the 4 surveys, for all sites, PfPR was predominantly higher in the 5-19 years group than in the other age categories. Occurrence of fever and anaemia was associated with high P. falciparum parasitaemia. Univariate analyses showed a significant association of anti-malarial treatment in 4 surveys (odds ratios [ORs]: 0.52, 0.52, 0.68, 0.41) and bed net use in 2 surveys (ORs: 0.63, 0.68, 1.03, 1.78) with lower risk of malaria infection. CONCLUSION Local PfPR differed substantially between sites and age groups. In children 6 months-4 years old, a significant decrease in prevalence over the 3 years was observed in 4 out of the 8 study sites. Trial registration Clinical Trials.gov identifier: NCT01190202:NCT. GSK Study ID numbers: 114001.
Collapse
Affiliation(s)
- Chris Drakeley
- London School of Hygiene and Tropical Medicine, London, UK
| | - Salim Abdulla
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania.
| | - Selidji Todagbe Agnandji
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - José Francisco Fernandes
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Peter Kremsner
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Bertrand Lell
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Ludovic Mewono
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Bache Emmanuel Bache
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Michael Gabriel Mihayo
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania
| | - Omar Juma
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania
| | - Marcel Tanner
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Halidou Tinto
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Salou Diallo
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | | | - Umberto D'Alessandro
- London School of Hygiene and Tropical Medicine, London, UK.,Medical Research Council Unit, The Gambia, Banjul, Gambia
| | | | | | | | | | | | | | | | - George Adjei
- Kintampo Health Research Center, Kintampo, Ghana
| | | | | | - Seth Owusu-Agyei
- London School of Hygiene and Tropical Medicine, London, UK.,Kintampo Health Research Center, Kintampo, Ghana
| | - Brian Greenwood
- London School of Hygiene and Tropical Medicine, London, UK.,Kintampo Health Research Center, Kintampo, Ghana
| | - Samwel Gesase
- National Institute for Medical Research, Korogwe, Tanzania
| | - John Lusingu
- National Institute for Medical Research, Korogwe, Tanzania
| | - Coline Mahende
- National Institute for Medical Research, Korogwe, Tanzania
| | - Robert Mongi
- National Institute for Medical Research, Korogwe, Tanzania
| | - Method Segeja
- National Institute for Medical Research, Korogwe, Tanzania
| | - Samuel Adjei
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - Alex Agyekum
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - Daniel Ansong
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - John Tanko Bawa
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | | | | | | | | | - Peter Maenje
- University of North Carolina Project, Lilongwe, Malawi
| | | | - Terrell Carter
- The PATH Malaria Vaccine Initiative, Washington, D.C., USA
| | | | - David C Kaslow
- The PATH Malaria Vaccine Initiative, Washington, D.C., USA
| | - Effua Usuf
- Medical Research Council Unit, The Gambia, Banjul, Gambia.,GSK Vaccines, Wavre, Belgium
| | | | | |
Collapse
|
18
|
Grenham A, Villafana T. Vaccine development and trials in low and lower-middle income countries: Key issues, advances and future opportunities. Hum Vaccin Immunother 2017; 13:2192-2199. [PMID: 28758824 PMCID: PMC5617553 DOI: 10.1080/21645515.2017.1356495] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/09/2017] [Accepted: 07/03/2017] [Indexed: 10/19/2022] Open
Abstract
Over the past 10 years there has been an increase in the number of vaccine clinical studies conducted in resource limited countries. These include vaccine trials for diseases such as malaria and dengue fever which are endemic to many low and lower-middle income countries. Concurrent with the increase in the number of trials, has been the increase and improvement in local infrastructure to enable the appropriate conduct and oversight of trials in these settings, including strengthening of local scientific capabilities, ethical and regulatory oversight. While significant advances have been made, there remain gaps to be addressed including strengthening pharmacovigilance in these regions. There are also opportunities to establish novel collaborations to address diseases specific to these populations including strengthening local manufacturers, new ways to engage established large pharmaceutical companies and leveraging established global infrastructure and pathways to develop innovative products beyond vaccines.
Collapse
Affiliation(s)
- Amy Grenham
- MedImmune, One MedImmune Way, Gaithersburg, MD, USA
| | | |
Collapse
|
19
|
Collins KA, Snaith R, Cottingham MG, Gilbert SC, Hill AVS. Enhancing protective immunity to malaria with a highly immunogenic virus-like particle vaccine. Sci Rep 2017; 7:46621. [PMID: 28422178 PMCID: PMC5395940 DOI: 10.1038/srep46621] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 03/03/2017] [Indexed: 12/11/2022] Open
Abstract
The leading malaria vaccine in development is the circumsporozoite protein (CSP)-based particle vaccine, RTS,S, which targets the pre-erythrocytic stage of Plasmodium falciparum infection. It induces modest levels of protective efficacy, thought to be mediated primarily by CSP-specific antibodies. We aimed to enhance vaccine efficacy by generating a more immunogenic CSP-based particle vaccine and therefore developed a next-generation RTS,S-like vaccine, called R21. The major improvement is that in contrast to RTS,S, R21 particles are formed from a single CSP-hepatitis B surface antigen (HBsAg) fusion protein, and this leads to a vaccine composed of a much higher proportion of CSP than in RTS,S. We demonstrate that in BALB/c mice R21 is immunogenic at very low doses and when administered with the adjuvants Abisco-100 and Matrix-M it elicits sterile protection against transgenic sporozoite challenge. Concurrent induction of potent cellular and humoral immune responses was also achieved by combining R21 with TRAP-based viral vectors and protective efficacy was significantly enhanced. In addition, in contrast to RTS,S, only a minimal antibody response to the HBsAg carrier was induced. These studies identify an anti-sporozoite vaccine component that may improve upon the current leading malaria vaccine RTS,S. R21 is now under evaluation in Phase 1/2a clinical trials.
Collapse
Affiliation(s)
- Katharine A Collins
- The Jenner Institute Laboratories, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Rebecca Snaith
- The Jenner Institute Laboratories, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Matthew G Cottingham
- The Jenner Institute Laboratories, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Sarah C Gilbert
- The Jenner Institute Laboratories, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Adrian V S Hill
- The Jenner Institute Laboratories, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| |
Collapse
|
20
|
Doussau A, Grady C. Deciphering assumptions about stepped wedge designs: the case of Ebola vaccine research. JOURNAL OF MEDICAL ETHICS 2016; 42:797-804. [PMID: 27754861 DOI: 10.1136/medethics-2015-103292] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 08/01/2016] [Accepted: 09/19/2016] [Indexed: 06/06/2023]
Abstract
Ethical concerns about randomising persons to a no-treatment arm in the context of Ebola epidemic led to consideration of alternative designs. The stepped wedge (SW) design, in which participants or clusters are randomised to receive an intervention at different time points, gained popularity. Common arguments in favour of using this design are (1) when an intervention is likely to do more good than harm, (2) all participants should receive the experimental intervention at some time point during the study and (3) the design might be preferable for practical reasons. We examine these assumptions when considering Ebola vaccine research. First, based on the claim that a stepped wedge design is indicated when it is likely that the intervention will do more good than harm, we reviewed published and ongoing SW trials to explore previous use of this design to test experimental drugs or vaccines, and found that SW design has never been used for trials of experimental drugs or vaccines. Given that Ebola vaccines were all experimental with no prior efficacy data, the use of a stepped wedge design would have been unprecedented. Second, we show that it is rarely true that all participants receive the intervention in SW studies, but rather, depending on certain design features, all clusters receive the intervention. Third, we explore whether the SW design is appealing for feasibility reasons and point out that there is significant complexity. In the setting of the Ebola epidemic, spatiotemporal variation may have posed problematic challenges to a stepped wedge design for vaccine research. Finally, we propose a set of points to consider for scientific reviewers and ethics committees regarding proposals for SW designs.
Collapse
Affiliation(s)
- Adélaïde Doussau
- Department of Bioethics, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Christine Grady
- Department of Bioethics, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
21
|
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]
|
22
|
Comeau JL, Chan J, Macartney KK. New Vaccines on the Horizon. CURRENT PEDIATRICS REPORTS 2016. [DOI: 10.1007/s40124-016-0109-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
23
|
Oneko M, Kariuki S, Muturi-Kioi V, Otieno K, Otieno VO, Williamson JM, Folster J, Parsons MB, Slutsker L, Mahon BE, Hamel MJ. Emergence of Community-Acquired, Multidrug-Resistant Invasive Nontyphoidal Salmonella Disease in Rural Western Kenya, 2009-2013. Clin Infect Dis 2016; 61 Suppl 4:S310-6. [PMID: 26449946 DOI: 10.1093/cid/civ674] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Nontyphoidal Salmonella (NTS), mainly serotypes Typhimurium and Enteritidis, cause invasive infections with high mortality in children in sub-Saharan Africa. Multidrug resistance is common, and resistance to third-generation cephalosporins has emerged. METHODS We reviewed clinical features, outcomes, and antimicrobial resistance patterns in invasive NTS infections among children aged 6 weeks to 5 years participating in malaria vaccine studies in an area of high malaria and human immunodeficiency virus (HIV) transmission in Siaya, western Kenya. Blood culture was performed in hospitalized children and pediatric outpatients with prolonged fever. RESULTS From July 2009 to December 2013, 1696 children aged 6 weeks to 17 months were enrolled into vaccine trials and followed for up to 53 months. We obtained 1692 blood cultures from 847 children. Of 134 bacterial pathogens isolated, 102 (76.1%) were Salmonella serogroup B or D. Invasive NTS disease occurred in 94 (5.5%) children, with an incidence of 1870, 4134, and 6510 episodes per 100 000 person-years overall, in infants, and in HIV-infected children, respectively. Malaria infection within the past 2 weeks occurred in 18.8% (3/16) of invasive NTS episodes in HIV-infected and 66.2% (53/80) in HIV-uninfected children. Case fatality rate was 3.1%. Salmonella group B resistant to ceftriaxone emerged in 2009 and 2010 (6.2% [2/32 isolates]), rising to 56.5% (13/23 isolates) in 2012 and 2013. CONCLUSIONS Incidence of invasive NTS disease was high in this area of high malaria and HIV transmission, especially in HIV-infected children. Rapidly emerging resistance against ceftriaxone requires urgent reevaluation of antibiotic recommendations and primary prevention of exposure to Salmonella.
Collapse
Affiliation(s)
- Martina Oneko
- Kenya Medical Research Institute/Centre for Global Health Research, Kisumu
| | - Simon Kariuki
- Kenya Medical Research Institute/Centre for Global Health Research, Kisumu
| | | | - Kephas Otieno
- Kenya Medical Research Institute/Centre for Global Health Research, Kisumu
| | - Vincent O Otieno
- Kenya Medical Research Institute/Centre for Global Health Research, Kisumu
| | | | - Jason Folster
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | | | - Barbara E Mahon
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Mary J Hamel
- Centers for Disease Control and Prevention, Atlanta, Georgia
| |
Collapse
|
24
|
Singh K, Mehta S. The clinical development process for a novel preventive vaccine: An overview. J Postgrad Med 2016; 62:4-11. [PMID: 26732191 PMCID: PMC4944327 DOI: 10.4103/0022-3859.173187] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Each novel vaccine candidate needs to be evaluated for safety, immunogenicity, and protective efficacy in humans before it is licensed for use. After initial safety evaluation in healthy adults, each vaccine candidate follows a unique development path. This article on clinical development gives an overview on the development path based on the expectations of various guidelines issued by the World Health Organization (WHO), the European Medicines Agency (EMA), and the United States Food and Drug Administration (USFDA). The manuscript describes the objectives, study populations, study designs, study site, and outcome(s) of each phase (Phase I-III) of a clinical trial. Examples from the clinical development of a malaria vaccine candidate, a rotavirus vaccine, and two vaccines approved for human papillomavirus (HPV) have also been discussed. The article also tabulates relevant guidelines, which can be referred to while drafting the development path of a novel vaccine candidate.
Collapse
Affiliation(s)
- K Singh
- Malaria Vaccine Development Program (MVDP), International Centre for Genetic Engineering and Biotechnology (ICGEB) Campus, New Delhi, India
| | | |
Collapse
|
25
|
Birkett AJ. Status of vaccine research and development of vaccines for malaria. Vaccine 2016; 34:2915-2920. [PMID: 26993333 DOI: 10.1016/j.vaccine.2015.12.074] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 12/22/2015] [Indexed: 11/17/2022]
Abstract
Despite recent progress in reducing deaths attributable to malaria, it continues to claim approximately 500,000 lives per year and is associated with approximately 200 million infections. New tools, including safe and effective vaccines, are needed to ensure that the gains of the last 15 years are leveraged toward achieving the ultimate goal of malaria parasite eradication. In 2015, the European Medicines Agency announced the adoption of a positive opinion for the malaria vaccine candidate most advanced in development, RTS,S/AS01, which provides modest protection against clinical malaria; in early 2016, WHO recommended large-scale pilot implementations of RTS,S in settings of moderate-to-high malaria transmission. In alignment with these advancements, the community goals and preferred product characteristics for next-generation vaccines have been updated to inform the development of vaccines that are highly efficacious in preventing clinical malaria, and those needed to accelerate parasite elimination. Next-generation vaccines, targeting all stages of the parasite lifecycle, are in early-stage development with the most advanced in Phase 2 trials. Importantly, progress is being made in the definition of feasible regulatory pathways to accelerate timelines, including for vaccines designed to interrupt transmission of parasites from humans to mosquitoes. The continued absence of financially lucrative, high-income markets to drive investment in malaria vaccine development points to continued heavy reliance on public and philanthropic funding.
Collapse
Affiliation(s)
- Ashley J Birkett
- PATH Malaria Vaccine Initiative (MVI), 55 Massachusetts Avenue NW, Suite 1000, Washington, DC 20001-2621, USA.
| |
Collapse
|
26
|
Gonçalves BP, Prevots DR, Kabyemela E, Fried M, Duffy PE. Preparing for future efficacy trials of severe malaria vaccines. Vaccine 2016; 34:1865-7. [PMID: 26923455 DOI: 10.1016/j.vaccine.2016.02.053] [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] [Received: 11/18/2015] [Revised: 02/15/2016] [Accepted: 02/17/2016] [Indexed: 10/22/2022]
Abstract
Severe malaria is a major cause of mortality in children, but comprises only a small proportion of Plasmodium falciparum infections in naturally exposed populations. The evaluation of vaccines that prevent severe falciparum disease will require clinical trials whose primary efficacy endpoint will be severe malaria risk during follow-up. Here, we show that such trials are feasible with fewer than 1000 participants in areas with intense malaria transmission during the age interval when severe malaria incidence peaks.
Collapse
Affiliation(s)
- Bronner P Gonçalves
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States; Laboratory of Clinical Infectious Diseases-Epidemiology Unit, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States
| | - D Rebecca Prevots
- Laboratory of Clinical Infectious Diseases-Epidemiology Unit, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States
| | - Edward Kabyemela
- MOMS Project, Seattle Biomedical Research Institute (currently Center for Infectious Disease Research), Seattle, WA, United States; Muheza Designated District Hospital, Muheza, Tanzania
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States; MOMS Project, Seattle Biomedical Research Institute (currently Center for Infectious Disease Research), Seattle, WA, United States; Muheza Designated District Hospital, Muheza, Tanzania
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States; MOMS Project, Seattle Biomedical Research Institute (currently Center for Infectious Disease Research), Seattle, WA, United States; Muheza Designated District Hospital, Muheza, Tanzania.
| |
Collapse
|
27
|
Analysis of the immune response of a new malaria vaccine based on the modification of cryptic epitopes. Parasitol Res 2016; 115:1907-13. [PMID: 26833322 DOI: 10.1007/s00436-016-4931-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/19/2016] [Indexed: 10/22/2022]
Abstract
Malaria is a severe, life-threatening infectious disease that endangers human health. However, there are no vaccines or immune strategy of vaccines succeeding in both erythrocytic and pre-erythrocytic stage. During the liver stage of the Plasmodium life cycle, sporozoites invade the host liver cells. The sporozoites, then, induce a cellular immune response via the major histocompatibility complex (MHC) molecules on their surfaces. The cytotoxic T lymphocytes (CTLs) then recognize the corresponding antigen-MHC complex on the surfaces of these infected liver cells and kill them. However, dominant epitopes with high MHC affinity are prone to mutation due to immune selection pressure. CTLs evoked by the original dominant epitopes cannot recognize the mutated epitopes, leading to immune evasion. In this study, we have modified the cryptic epitopes of different antigens in the sporozoite and liver stages of Plasmodium falciparum to increase their immunogenicity without changing T cell antigen receptor (TCR)-peptide binding specificity. In addition, we have also added an important erythrocytic phase protective antigen, named apical membrane antigen 1 (AMA-1), to this process with the goal of constructing a complex multi-stage, multi-epitope recombinant DNA vaccine against P. falciparum. The vaccine was tested in HHD-2 mice. The method involved multiple stages of the P. falciparum life cycle as well as elucidation both humoral and cellular immunity. The conclusion drawn from the study was that the vaccine might provide an important theoretical and practical basis for generating effective preventative or therapeutic vaccine against P. falciparum.
Collapse
|
28
|
Sauboin CJ, Van Bellinghen LA, Van De Velde N, Van Vlaenderen I. Potential public health impact of RTS,S malaria candidate vaccine in sub-Saharan Africa: a modelling study. Malar J 2015; 14:524. [PMID: 26702637 PMCID: PMC4690265 DOI: 10.1186/s12936-015-1046-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 12/09/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Adding malaria vaccination to existing interventions could help to reduce the health burden due to malaria. This study modelled the potential public health impact of the RTS,S candidate malaria vaccine in 42 malaria-endemic countries in sub-Saharan Africa. METHODS An individual-based Markov cohort model was constructed with three categories of malaria transmission intensity and six successive malaria immunity levels. The cycle time was 5 days. Vaccination was assumed to reduce the risk of infection, with no other effects. Vaccine efficacy was assumed to wane exponentially over time. Malaria incidence and vaccine efficacy data were taken from a Phase III trial of the RTS,S vaccine with 18 months of follow-up (NCT00866619). The model was calibrated to reproduce the malaria incidence in the control arm of the trial in each transmission category and published age distribution data. Individual-level heterogeneity in malaria exposure and vaccine protection was accounted for. Parameter uncertainty and variability were captured by using stochastic model transitions. The model followed a cohort from birth to 10 years of age without malaria vaccination, or with RTS,S malaria vaccination administered at age 6, 10 and 14 weeks or at age 6, 7-and-a-half and 9 months. Median and 95% confidence intervals were calculated for the number of clinical malaria cases, severe cases, malaria hospitalizations and malaria deaths expected to be averted by each vaccination strategy. Univariate sensitivity analysis was conducted by varying the values of key input parameters. RESULTS Vaccination assuming the coverage of diphtheria-tetanus-pertussis (DTP3) at age 6, 10 and 14 weeks is estimated to avert over five million clinical malaria cases, 119,000 severe malaria cases, 98,600 malaria hospitalizations and 31,000 malaria deaths in the 42 countries over the 10-year period. Vaccination at age 6, 7-and-a-half and 9 months with 75% of DTP3 coverage is estimated to avert almost 12.5 million clinical malaria cases, 250,000 severe malaria cases, 208,000 malaria hospitalizations and 65,400 malaria deaths in the 42 countries. Univariate sensitivity analysis indicated that for both vaccination strategies, the parameters with the largest impact on the malaria mortality estimates were waning of vaccine efficacy and malaria case-fatality rate. CONCLUSIONS Addition of RTS,S malaria vaccination to existing malaria interventions is estimated to reduce substantially the incidence of clinical malaria, severe malaria, malaria hospitalizations and malaria deaths across 42 countries in sub-Saharan Africa.
Collapse
|
29
|
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.
Collapse
|
30
|
White MT, Verity R, Churcher TS, Ghani AC. Vaccine approaches to malaria control and elimination: Insights from mathematical models. Vaccine 2015; 33:7544-50. [PMID: 26476361 DOI: 10.1016/j.vaccine.2015.09.099] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 09/14/2015] [Accepted: 09/15/2015] [Indexed: 12/16/2022]
Abstract
A licensed malaria vaccine would provide a valuable new tool for malaria control and elimination efforts. Several candidate vaccines targeting different stages of the malaria parasite's lifecycle are currently under development, with one candidate, RTS,S/AS01 for the prevention of Plasmodium falciparum infection, having recently completed Phase III trials. Predicting the public health impact of a candidate malaria vaccine requires using clinical trial data to estimate the vaccine's efficacy profile--the initial efficacy following vaccination and the pattern of waning of efficacy over time. With an estimated vaccine efficacy profile, the effects of vaccination on malaria transmission can be simulated with the aid of mathematical models. Here, we provide an overview of methods for estimating the vaccine efficacy profiles of pre-erythrocytic vaccines and transmission-blocking vaccines from clinical trial data. In the case of RTS,S/AS01, model estimates from Phase II clinical trial data indicate a bi-phasic exponential profile of efficacy against infection, with efficacy waning rapidly in the first 6 months after vaccination followed by a slower rate of waning over the next 4 years. Transmission-blocking vaccines have yet to be tested in large-scale Phase II or Phase III clinical trials so we review ongoing work investigating how a clinical trial might be designed to ensure that vaccine efficacy can be estimated with sufficient statistical power. Finally, we demonstrate how parameters estimated from clinical trials can be used to predict the impact of vaccination campaigns on malaria using a mathematical model of malaria transmission.
Collapse
Affiliation(s)
- Michael T White
- MRC Centre for Outbreak Analysis & Modeling, Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London W2 1PG, UK.
| | - Robert Verity
- MRC Centre for Outbreak Analysis & Modeling, Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London W2 1PG, UK
| | - Thomas S Churcher
- MRC Centre for Outbreak Analysis & Modeling, Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London W2 1PG, UK
| | - Azra C Ghani
- MRC Centre for Outbreak Analysis & Modeling, Department of Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London W2 1PG, UK
| |
Collapse
|
31
|
Birkett AJ. Building an effective malaria vaccine pipeline to address global needs. Vaccine 2015; 33:7538-43. [PMID: 26469721 DOI: 10.1016/j.vaccine.2015.09.111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 09/25/2015] [Accepted: 09/29/2015] [Indexed: 02/08/2023]
Abstract
Despite impressive gains over the last 15 years in reducing the mortality associated with malaria, it remains a public health emergency. New interventions, such as vaccines, are needed to ensure that previous gains serve as a foundation for future progress. Vaccines have the potential to prevent severe disease and death in those most vulnerable, and to accelerate elimination and eradication by breaking the cycle of parasite transmission. The pipeline is as healthy as it has ever been, with approaches targeting different stages of the parasite lifecycle using an array of technologies. This article reviews recent progress and reviews key considerations in the quest to develop products that are aligned with the unmet medical need.
Collapse
Affiliation(s)
- Ashley J Birkett
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Suite 1000, Washington, DC 20001-2621, USA.
| |
Collapse
|
32
|
RTS,S: Toward a first landmark on the Malaria Vaccine Technology Roadmap. Vaccine 2015; 33:7425-32. [PMID: 26431982 DOI: 10.1016/j.vaccine.2015.09.061] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 09/08/2015] [Accepted: 09/15/2015] [Indexed: 01/07/2023]
Abstract
The Malaria Vaccine Technology Roadmap calls for a 2015 landmark goal of a first-generation malaria vaccine that has protective efficacy against severe disease and death, lasting longer than one year. This review focuses on product development efforts over the last five years of RTS,S, a pre-erythrocytic, recombinant subunit, adjuvanted, candidate malaria vaccine designed with this goal of a first-generation malaria vaccine in mind. RTS,S recently completed a successful pivotal Phase III safety, efficacy and immunogenicity study. Although vaccine efficacy was found to be modest, a substantial number of cases of clinical malaria were averted over a 3-4 years period, particularly in settings of significant disease burden. European regulators have subsequently adopted a positive opinion under the Article 58 procedure for an indication of active immunization of children aged 6 weeks up to 17 months against malaria caused by Plasmodium falciparum and against hepatitis B. Further evaluations of the benefit, risk, feasibility and cost-effectiveness of RTS,S are now anticipated through policy and financing reviews at the global and national levels.
Collapse
|
33
|
Hoffman SL, Vekemans J, Richie TL, Duffy PE. The march toward malaria vaccines. Vaccine 2015; 33 Suppl 4:D13-23. [PMID: 26324116 DOI: 10.1016/j.vaccine.2015.07.091] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/25/2015] [Accepted: 07/27/2015] [Indexed: 01/14/2023]
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.
Collapse
Affiliation(s)
| | | | | | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| |
Collapse
|
34
|
Penny MA, Galactionova K, Tarantino M, Tanner M, Smith TA. The public health impact of malaria vaccine RTS,S in malaria endemic Africa: country-specific predictions using 18 month follow-up Phase III data and simulation models. BMC Med 2015; 13:170. [PMID: 26219380 PMCID: PMC4518512 DOI: 10.1186/s12916-015-0408-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/25/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The RTS,S/AS01 malaria vaccine candidate recently completed Phase III trials in 11 African sites. Recommendations for its deployment will partly depend on predictions of public health impact in endemic countries. Previous predictions of these used only limited information on underlying vaccine properties and have not considered country-specific contextual data. METHODS Each Phase III trial cohort was simulated explicitly using an ensemble of individual-based stochastic models, and many hypothetical vaccine profiles. The true profile was estimated by Bayesian fitting of these models to the site- and time-specific incidence of clinical malaria in both trial arms over 18 months of follow-up. Health impacts of implementation via two vaccine schedules in 43 endemic sub-Saharan African countries, using country-specific prevalence, access to care, immunisation coverage and demography data, were predicted via weighted averaging over many simulations. RESULTS The efficacy against infection of three doses of vaccine was initially approximately 65 % (when immunising 6-12 week old infants) and 80 % (children 5-17 months old), with a 1 year half-life (exponential decay). Either schedule will avert substantial disease, but predicted impact strongly depends on the decay rate of vaccine effects and average transmission intensity. CONCLUSIONS For the first time Phase III site- and time-specific data were available to estimate both the underlying profile of RTS,S/AS01 and likely country-specific health impacts. Initial efficacy will probably be high, but decay rapidly. Adding RTS,S to existing control programs, assuming continuation of current levels of malaria exposure and of health system performance, will potentially avert 100-580 malaria deaths and 45,000 to 80,000 clinical episodes per 100,000 fully vaccinated children over an initial 10-year phase.
Collapse
Affiliation(s)
- Melissa A Penny
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
| | - Katya Galactionova
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
| | - Michael Tarantino
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
| | - Marcel Tanner
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
| | - Thomas A Smith
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
| |
Collapse
|
35
|
Efficacy and safety of RTS,S/AS01 malaria vaccine with or without a booster dose in infants and children in Africa: final results of a phase 3, individually randomised, controlled trial. Lancet 2015; 386:31-45. [PMID: 25913272 PMCID: PMC5626001 DOI: 10.1016/s0140-6736(15)60721-8] [Citation(s) in RCA: 956] [Impact Index Per Article: 106.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND The efficacy and safety of the RTS,S/AS01 candidate malaria vaccine during 18 months of follow-up have been published previously. Herein, we report the final results from the same trial, including the efficacy of a booster dose. METHODS From March 27, 2009, until Jan 31, 2011, children (age 5-17 months) and young infants (age 6-12 weeks) were enrolled at 11 centres in seven countries in sub-Saharan Africa. Participants were randomly assigned (1:1:1) at first vaccination by block randomisation with minimisation by centre to receive three doses of RTS,S/AS01 at months 0, 1, and 2 and a booster dose at month 20 (R3R group); three doses of RTS,S/AS01 and a dose of comparator vaccine at month 20 (R3C group); or a comparator vaccine at months 0, 1, 2, and 20 (C3C [control group]). Participants were followed up until Jan 31, 2014. Cases of clinical and severe malaria were captured through passive case detection. Serious adverse events (SAEs) were recorded. Analyses were by modified intention to treat and per protocol. The coprimary endpoints were the occurrence of malaria over 12 months after dose 3 in each age category. In this final analysis, we present data for the efficacy of the booster on the occurrence of malaria. Vaccine efficacy (VE) against clinical malaria was analysed by negative binomial regression and against severe malaria by relative risk reduction. This trial is registered with ClinicalTrials.gov, number NCT00866619. FINDINGS 8922 children and 6537 young infants were included in the modified intention-to-treat analyses. Children were followed up for a median of 48 months (IQR 39-50) and young infants for 38 months (34-41) after dose 1. From month 0 until study end, compared with 9585 episodes of clinical malaria that met the primary case definition in children in the C3C group, 6616 episodes occurred in the R3R group (VE 36·3%, 95% CI 31·8-40·5) and 7396 occurred in the R3C group (28·3%, 23·3-32·9); compared with 171 children who experienced at least one episode of severe malaria in the C3C group, 116 children experienced at least one episode of severe malaria in the R3R group (32·2%, 13·7 to 46·9) and 169 in the R3C group (1·1%, -23·0 to 20·5). In young infants, compared with 6170 episodes of clinical malaria that met the primary case definition in the C3C group, 4993 episodes occurred in the R3R group (VE 25·9%, 95% CI 19·9-31·5) and 5444 occurred in the R3C group (18·3%, 11·7-24·4); and compared with 116 infants who experienced at least one episode of severe malaria in the C3C group, 96 infants experienced at least one episode of severe malaria in the R3R group (17·3%, 95% CI -9·4 to 37·5) and 104 in the R3C group (10·3%, -17·9 to 31·8). In children, 1774 cases of clinical malaria were averted per 1000 children (95% CI 1387-2186) in the R3R group and 1363 per 1000 children (995-1797) in the R3C group. The numbers of cases averted per 1000 young infants were 983 (95% CI 592-1337) in the R3R group and 558 (158-926) in the R3C group. The frequency of SAEs overall was balanced between groups. However, meningitis was reported as a SAE in 22 children: 11 in the R3R group, ten in the R3C group, and one in the C3C group. The incidence of generalised convulsive seizures within 7 days of RTS,S/AS01 booster was 2·2 per 1000 doses in young infants and 2·5 per 1000 doses in children. INTERPRETATION RTS,S/AS01 prevented a substantial number of cases of clinical malaria over a 3-4 year period in young infants and children when administered with or without a booster dose. Efficacy was enhanced by the administration of a booster dose in both age categories. Thus, the vaccine has the potential to make a substantial contribution to malaria control when used in combination with other effective control measures, especially in areas of high transmission. FUNDING GlaxoSmithKline Biologicals SA and the PATH Malaria Vaccine Initiative.
Collapse
|
36
|
Abstract
The development of a highly effective malaria vaccine remains a key goal to aid in the control and eventual eradication of this devastating parasitic disease. The field has made huge strides in recent years, with the first-generation vaccine RTS,S showing modest efficacy in a Phase III clinical trial. The updated 2030 Malaria Vaccine Technology Roadmap calls for a second generation vaccine to achieve 75% efficacy over two years for both Plasmodium falciparum and Plasmodium vivax, and for a vaccine that can prevent malaria transmission. Whole-parasite immunisation approaches and combinations of pre-erythrocytic subunit vaccines are now reporting high-level efficacy, whilst exciting new approaches to the development of blood-stage and transmission-blocking vaccine subunit components are entering clinical development. The development of a highly effective multi-component multi-stage subunit vaccine now appears to be a realistic ambition. This review will cover these recent developments in malaria vaccinology.
Collapse
|
37
|
Local tolerance and systemic toxicity of single and repeated intramuscular administrations of two different formulations of the RTS,S malaria candidate vaccine in rabbits. Regul Toxicol Pharmacol 2015; 71:269-78. [DOI: 10.1016/j.yrtph.2014.12.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 12/01/2014] [Accepted: 12/19/2014] [Indexed: 11/22/2022]
|
38
|
Immunogenicity and safety of the candidate RTS,S/AS01 vaccine in young Nigerian children: A randomized, double-blind, lot-to-lot consistency trial. Vaccine 2014; 32:6556-62. [DOI: 10.1016/j.vaccine.2014.07.067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/03/2014] [Accepted: 07/17/2014] [Indexed: 11/16/2022]
|
39
|
Efficacy and safety of the RTS,S/AS01 malaria vaccine during 18 months after vaccination: a phase 3 randomized, controlled trial in children and young infants at 11 African sites. PLoS Med 2014; 11:e1001685. [PMID: 25072396 PMCID: PMC4114488 DOI: 10.1371/journal.pmed.1001685] [Citation(s) in RCA: 302] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 06/18/2014] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND A malaria vaccine could be an important addition to current control strategies. We report the safety and vaccine efficacy (VE) of the RTS,S/AS01 vaccine during 18 mo following vaccination at 11 African sites with varying malaria transmission. METHODS AND FINDINGS 6,537 infants aged 6-12 wk and 8,923 children aged 5-17 mo were randomized to receive three doses of RTS,S/AS01 or comparator vaccine. VE against clinical malaria in children during the 18 mo after vaccine dose 3 (per protocol) was 46% (95% CI 42% to 50%) (range 40% to 77%; VE, p<0.01 across all sites). VE during the 20 mo after vaccine dose 1 (intention to treat [ITT]) was 45% (95% CI 41% to 49%). VE against severe malaria, malaria hospitalization, and all-cause hospitalization was 34% (95% CI 15% to 48%), 41% (95% CI 30% to 50%), and 19% (95% CI 11% to 27%), respectively (ITT). VE against clinical malaria in infants was 27% (95% CI 20% to 32%, per protocol; 27% [95% CI 21% to 33%], ITT), with no significant protection against severe malaria, malaria hospitalization, or all-cause hospitalization. Post-vaccination anti-circumsporozoite antibody geometric mean titer varied from 348 to 787 EU/ml across sites in children and from 117 to 335 EU/ml in infants (per protocol). VE waned over time in both age categories (Schoenfeld residuals p<0.001). The number of clinical and severe malaria cases averted per 1,000 children vaccinated ranged across sites from 37 to 2,365 and from -1 to 49, respectively; corresponding ranges among infants were -10 to 1,402 and -13 to 37, respectively (ITT). Meningitis was reported as a serious adverse event in 16/5,949 and 1/2,974 children and in 9/4,358 and 3/2,179 infants in the RTS,S/AS01 and control groups, respectively. CONCLUSIONS RTS,S/AS01 prevented many cases of clinical and severe malaria over the 18 mo after vaccine dose 3, with the highest impact in areas with the greatest malaria incidence. VE was higher in children than in infants, but even at modest levels of VE, the number of malaria cases averted was substantial. RTS,S/AS01 could be an important addition to current malaria control in Africa. TRIAL REGISTRATION www.ClinicalTrials.gov NCT00866619 Please see later in the article for the Editors' Summary.
Collapse
|
40
|
Nico D, Gomes DC, Palatnik-de-Sousa I, Morrot A, Palatnik M, Palatnik-de-Sousa CB. Leishmania donovani Nucleoside Hydrolase Terminal Domains in Cross-Protective Immunotherapy Against Leishmania amazonensis Murine Infection. Front Immunol 2014; 5:273. [PMID: 24966857 PMCID: PMC4052736 DOI: 10.3389/fimmu.2014.00273] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/27/2014] [Indexed: 11/13/2022] Open
Abstract
Nucleoside hydrolases of the Leishmania genus are vital enzymes for the replication of the DNA and conserved phylogenetic markers of the parasites. Leishmania donovani nucleoside hydrolase (NH36) induced a main CD4(+) T cell driven protective response against L. chagasi infection in mice which is directed against its C-terminal domain. In this study, we used the three recombinant domains of NH36: N-terminal domain (F1, amino acids 1-103), central domain (F2 aminoacids 104-198), and C-terminal domain (F3 amino acids 199-314) in combination with saponin and assayed their immunotherapeutic effect on Balb/c mice previously infected with L. amazonensis. We identified that the F1 and F3 peptides determined strong cross-immunotherapeutic effects, reducing the size of footpad lesions to 48 and 64%, and the parasite load in footpads to 82.6 and 81%, respectively. The F3 peptide induced the strongest anti-NH36 antibody response and intradermal response (IDR) against L. amazonenis and a high secretion of IFN-γ and TNF-α with reduced levels of IL-10. The F1 vaccine, induced similar increases of IgG2b antibodies and IFN-γ and TNF-α levels, but no IDR and no reduction of IL-10. The multiparameter flow cytometry analysis was used to assess the immune response after immunotherapy and disclosed that the degree of the immunotherapeutic effect is predicted by the frequencies of the CD4(+) and CD8(+) T cells producing IL-2 or TNF-α or both. Total frequencies and frequencies of double-cytokine CD4 T cell producers were enhanced by F1 and F3 vaccines. Collectively, our multifunctional analysis disclosed that immunotherapeutic protection improved as the CD4 responses progressed from 1+ to 2+, in the case of the F1 and F3 vaccines, and as the CD8 responses changed qualitatively from 1+ to 3+, mainly in the case of the F1 vaccine, providing new correlates of immunotherapeutic protection against cutaneous leishmaniasis in mice based on T-helper TH1 and CD8(+) mediated immune responses.
Collapse
Affiliation(s)
- Dirlei Nico
- Laboratório de Biologia e Bioquímica de Leishmania, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Daniele Crespo Gomes
- Laboratório de Biologia e Bioquímica de Leishmania, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Iam Palatnik-de-Sousa
- Programa de Pós Graduação em Metrologia, Laboratório de Biometrologia, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexandre Morrot
- Laboratório de Imunologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcos Palatnik
- Programa de Pós Graduação em Clínica Médica, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Clarisa Beatriz Palatnik-de-Sousa
- Laboratório de Biologia e Bioquímica de Leishmania, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| |
Collapse
|
41
|
Birkett AJ, Moorthy VS, Loucq C, Chitnis CE, Kaslow DC. Malaria vaccine R&D in the Decade of Vaccines: breakthroughs, challenges and opportunities. Vaccine 2014; 31 Suppl 2:B233-43. [PMID: 23598488 DOI: 10.1016/j.vaccine.2013.02.040] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 02/06/2013] [Accepted: 02/25/2013] [Indexed: 01/23/2023]
Abstract
While recent progress has been made in reducing malaria mortality with other interventions, vaccines are still urgently needed to further reduce the incidence of clinical disease, including during pregnancy, and to provide "herd protection" by blocking parasite transmission. The most clinically advanced candidate, RTS,S, is presently undergoing Phase 3 evaluation in young African children across 13 clinical sites in eight African countries. In the 12-month period following vaccination, RTS,S conferred approximately 50% protection from clinical Plasmodium falciparum disease in children aged 5-17 months, and approximately 30% protection in children aged 6-12 weeks when administered in conjunction with Expanded Program for Immunization (EPI) vaccines. The development of more highly efficacious vaccines to prevent clinical disease caused by both P. falciparum and Plasmodium vivax, as well as vaccines to support elimination efforts by inducing immunity that blocks malaria parasite transmission, are priorities. Some key barriers to malaria vaccine development include: a paucity of well-characterized target immunogens and an absence of clear correlates of protection to enable vaccine development targeting all stages of the P. falciparum and P. vivax lifecycles; a limited number of safe and effective delivery systems, including adjuvants, that induce potent, long-lived protective immunity, be it by antibody, CD4+, and/or CD8+ T cell responses; and, for vaccines designed to provide "herd protection" by targeting sexual stage and/or mosquito antigens, the lack of a clear clinical and regulatory pathway to licensure using non-traditional endpoints. Recommendations to overcome these, and other key challenges, are suggested in this document.
Collapse
Affiliation(s)
- Ashley J Birkett
- PATH Malaria Vaccine Initiative, Washington, DC 20001-2621, USA.
| | | | | | | | | |
Collapse
|
42
|
Seo MK, Baker P, Ngo KNL. Cost-effectiveness analysis of vaccinating children in Malawi with RTS,S vaccines in comparison with long-lasting insecticide-treated nets. Malar J 2014; 13:66. [PMID: 24564883 PMCID: PMC4016032 DOI: 10.1186/1475-2875-13-66] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 02/18/2014] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND New RTS,S malaria vaccines may soon be licensed, yet its cost-effectiveness is unknown. Before the widespread introduction of RTS,S vaccines, cost-effectiveness studies are needed to help inform governments in resource-poor settings about how best to prioritize between the new vaccine and existing malaria interventions. METHODS A Markov model simulated malaria progression in a hypothetical Malawian birth cohort. Parameters were based on published data. Three strategies were compared: no intervention, vaccination at one year, and long-lasting, insecticide-treated nets (LLINs) at birth. Both health service and societal perspectives were explored. Health outcomes were measured in disability-adjusted life years (DALYs) averted and costed in 2012 US$. Incremental cost-effectiveness ratios (ICERs) were calculated and extensive sensitivity analyses were conducted. Three times GDP per capita ($1,095) per DALY averted was used for a cost-effectiveness threshold, whilst one times GDP ($365) was considered 'very cost-effective'. RESULTS From a societal perspective the vaccine strategy was dominant. It averted 0.11 more DALYs than LLINs and 0.372 more DALYs than the no intervention strategy per person, while costing $10.04 less than LLINs and $59.74 less than no intervention. From a health service perspective the vaccine's ICER was $145.03 per DALY averted, and thus can be considered very cost-effective. The results were robust to changes in all variables except the vaccine and LLINs' duration of efficacy. Vaccines remained cost-effective even at the lowest assumed efficacy levels of 49.6% (mild malaria) and 14.2% (severe malaria), and the highest price of $15. However, from a societal perspective, if the vaccine duration efficacy was set below 2.69 years or the LLIN duration of efficacy was greater than 4.24 years then LLINs became the more cost-effective strategy. CONCLUSION The results showed that vaccinating Malawian children with RTS,S vaccines was very cost-effective from both a societal and a health service perspective. This result was robust to changes in most variables, including vaccine price and vaccine efficacy, but was sensitive to the duration of efficacy of the vaccine and LLINs. Given the best evidence currently available, vaccines can be considered as a very cost-effective component of Malawi's future malaria control programmes. However, long-term follow-up studies on both interventions are needed.
Collapse
Affiliation(s)
- Mikyung Kelly Seo
- MSc in Health Policy, Planning and Financing, London School of Hygiene and Tropical Medicine and London School of Economics, London, UK.
| | | | | |
Collapse
|
43
|
Salvador A, Hernández RM, Pedraz JL, Igartua M. Plasmodium falciparummalaria vaccines: current status, pitfalls and future directions. Expert Rev Vaccines 2014; 11:1071-86. [DOI: 10.1586/erv.12.87] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
44
|
Chamlian M, Bastos EL, Maciel C, Capurro ML, Miranda A, Silva AF, Torres MDT, Oliveira VX. A study of the anti-plasmodium activity of angiotensin II analogs. J Pept Sci 2013; 19:575-80. [DOI: 10.1002/psc.2534] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/06/2013] [Accepted: 06/10/2013] [Indexed: 12/15/2022]
Affiliation(s)
- Mayra Chamlian
- Centro de Ciências Naturais e Humanas; Universidade Federal do ABC; Santo André SP Brazil
| | - Erick L. Bastos
- Departamento de Química Fundamental; Universidade de São Paulo, Instituto de Química; São Paulo SP Brazil
| | - Ceres Maciel
- Instituto de Ciências Biomédicas; Universidade de São Paulo; São Paulo SP Brazil
| | - Margareth L. Capurro
- Instituto de Ciências Biomédicas; Universidade de São Paulo; São Paulo SP Brazil
| | - Antonio Miranda
- Departamento de Biofísica; Universidade Federal de São Paulo; São Paulo SP Brazil
| | - Adriana F. Silva
- Centro de Ciências Naturais e Humanas; Universidade Federal do ABC; Santo André SP Brazil
| | - Marcelo Der T. Torres
- Centro de Ciências Naturais e Humanas; Universidade Federal do ABC; Santo André SP Brazil
| | - Vani X. Oliveira
- Centro de Ciências Naturais e Humanas; Universidade Federal do ABC; Santo André SP Brazil
| |
Collapse
|
45
|
Heppner DG. The malaria vaccine--status quo 2013. Travel Med Infect Dis 2013; 11:2-7. [PMID: 23454205 DOI: 10.1016/j.tmaid.2013.01.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 01/24/2013] [Accepted: 01/24/2013] [Indexed: 01/23/2023]
Abstract
It has been 40 years since David Clyde's landmark induction of sterile immunity against deadly falciparum malaria through immunization by exposure to 1000 irradiated mosquitoes, and the first recombinant Plasmodium falciparum vaccine, RTS,S/AS01, is now in Phase III testing. Interim reports from this largest ever Phase III pediatric trial in Africa show the malaria vaccine decreased clinical and severe disease by 56% and 47% respectively in 5-17 month olds, and by 31% and 26% respectively in infants participating in the Expanded Programme on Immunization. Final data in 2014 will more fully describe the efficacy of RTS,S/AS01 over time against all falciparum malaria cases under a variety of transmission conditions, results essential for decisions on licensure and deployment. Meanwhile, candidate components of a second-generation malaria vaccine are emerging. A field trial of the polymorphic blood stage vaccine AMA-1/AS02 demonstrated no overall efficacy (ve = 17%, P = 0.18), yet a sieve analysis revealed allele-specific efficacy (ve = 64%, P = 0.03) against the vaccine strain, suggesting AMA-1 antigens could be part of a multicomponent vaccine. Initial trials of new antigens include the highly conserved pre-erythrocytic candidate PfCelTOS, a synthetic Plasmodium vivax circumsporozoite antigen VMP-001, and sexual stage vaccines containing antigens from both P. falciparum (Pfs25) and P. vivax (Pvs25) intended to interrupt transmission. Targets for a vaccine to protect against placental malaria, the leading remediable cause of low birth weight infants in Africa, have been identified. Lastly, renewed efforts are underway to develop a practical attenuated-sporozoite vaccine to recapture the promise of David Clyde's experiment.
Collapse
Affiliation(s)
- D Gray Heppner
- Heppner Associates, LLC, 9441 Brenner Court, Vienna, VA 22180-3402, USA.
| |
Collapse
|
46
|
Agnandji ST, Lell B, Fernandes JF, Abossolo BP, Methogo BGNO, Kabwende AL, Adegnika AA, Mordmüller B, Issifou S, Kremsner PG, Sacarlal J, Aide P, Lanaspa M, Aponte JJ, Machevo S, Acacio S, Bulo H, Sigauque B, Macete E, Alonso P, Abdulla S, Salim N, Minja R, Mpina M, Ahmed S, Ali AM, Mtoro AT, Hamad AS, Mutani P, Tanner M, Tinto H, D'Alessandro U, Sorgho H, Valea I, Bihoun B, Guiraud I, Kaboré B, Sombié O, Guiguemdé RT, Ouédraogo JB, Hamel MJ, Kariuki S, Oneko M, Odero C, Otieno K, Awino N, McMorrow M, Muturi-Kioi V, Laserson KF, Slutsker L, Otieno W, Otieno L, Otsyula N, Gondi S, Otieno A, Owira V, Oguk E, Odongo G, Woods JB, Ogutu B, Njuguna P, Chilengi R, Akoo P, Kerubo C, Maingi C, Lang T, Olotu A, Bejon P, Marsh K, Mwambingu G, Owusu-Agyei S, Asante KP, Osei-Kwakye K, Boahen O, Dosoo D, Asante I, Adjei G, Kwara E, Chandramohan D, Greenwood B, Lusingu J, Gesase S, Malabeja A, Abdul O, Mahende C, Liheluka E, Malle L, Lemnge M, Theander TG, Drakeley C, Ansong D, Agbenyega T, Adjei S, Boateng HO, Rettig T, Bawa J, Sylverken J, Sambian D, Sarfo A, Agyekum A, Martinson F, Hoffman I, Mvalo T, Kamthunzi P, Nkomo R, Tembo T, Tegha G, Tsidya M, Kilembe J, Chawinga C, Ballou WR, Cohen J, Guerra Y, Jongert E, Lapierre D, Leach A, Lievens M, Ofori-Anyinam O, Olivier A, Vekemans J, Carter T, Kaslow D, Leboulleux D, Loucq C, Radford A, Savarese B, Schellenberg D, Sillman M, Vansadia P. A phase 3 trial of RTS,S/AS01 malaria vaccine in African infants. N Engl J Med 2012; 367:2284-95. [PMID: 23136909 PMCID: PMC10915853 DOI: 10.1056/nejmoa1208394] [Citation(s) in RCA: 541] [Impact Index Per Article: 45.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND The candidate malaria vaccine RTS,S/AS01 reduced episodes of both clinical and severe malaria in children 5 to 17 months of age by approximately 50% in an ongoing phase 3 trial. We studied infants 6 to 12 weeks of age recruited for the same trial. METHODS We administered RTS,S/AS01 or a comparator vaccine to 6537 infants who were 6 to 12 weeks of age at the time of the first vaccination in conjunction with Expanded Program on Immunization (EPI) vaccines in a three-dose monthly schedule. Vaccine efficacy against the first or only episode of clinical malaria during the 12 months after vaccination, a coprimary end point, was analyzed with the use of Cox regression. Vaccine efficacy against all malaria episodes, vaccine efficacy against severe malaria, safety, and immunogenicity were also assessed. RESULTS The incidence of the first or only episode of clinical malaria in the intention-to-treat population during the 14 months after the first dose of vaccine was 0.31 per person-year in the RTS,S/AS01 group and 0.40 per person-year in the control group, for a vaccine efficacy of 30.1% (95% confidence interval [CI], 23.6 to 36.1). Vaccine efficacy in the per-protocol population was 31.3% (97.5% CI, 23.6 to 38.3). Vaccine efficacy against severe malaria was 26.0% (95% CI, -7.4 to 48.6) in the intention-to-treat population and 36.6% (95% CI, 4.6 to 57.7) in the per-protocol population. Serious adverse events occurred with a similar frequency in the two study groups. One month after administration of the third dose of RTS,S/AS01, 99.7% of children were positive for anti-circumsporozoite antibodies, with a geometric mean titer of 209 EU per milliliter (95% CI, 197 to 222). CONCLUSIONS The RTS,S/AS01 vaccine coadministered with EPI vaccines provided modest protection against both clinical and severe malaria in young infants. (Funded by GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative; RTS,S ClinicalTrials.gov number, NCT00866619.).
Collapse
|
47
|
Anders KL, Hay SI. Lessons from malaria control to help meet the rising challenge of dengue. THE LANCET. INFECTIOUS DISEASES 2012; 12:977-84. [PMID: 23174383 PMCID: PMC3574272 DOI: 10.1016/s1473-3099(12)70246-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Achievements in malaria control could inform efforts to control the increasing global burden of dengue. Better methods for quantifying dengue endemicity-equivalent to parasite prevalence surveys and endemicity mapping used for malaria-would help target resources, monitor progress, and advocate for investment in dengue prevention. Success in controlling malaria has been attributed to widespread implementation of interventions with proven efficacy. An improved evidence base is needed for large-scale delivery of existing and novel interventions for vector control, alongside continued investment in dengue drug and vaccine development. Control of dengue is unlikely to be achieved without coordinated international financial and technical support for national programmes, which has proven effective in reducing the global burden of malaria.
Collapse
Affiliation(s)
- Katherine L Anders
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.
| | | |
Collapse
|
48
|
Clement F, Dewar V, Van Braeckel E, Desombere I, Dewerchin M, Swysen C, Demoitié MA, Jongert E, Cohen J, Leroux-Roels G, Cambron P. Validation of an enzyme-linked immunosorbent assay for the quantification of human IgG directed against the repeat region of the circumsporozoite protein of the parasite Plasmodium falciparum. Malar J 2012; 11:384. [PMID: 23173602 PMCID: PMC3577486 DOI: 10.1186/1475-2875-11-384] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 10/23/2012] [Indexed: 11/13/2022] Open
Abstract
Background Several pre-erythrocytic malaria vaccines based on the circumsporozoite protein (CSP) antigen of Plasmodium falciparum are in clinical development. Vaccine immunogenicity is commonly evaluated by the determination of anti-CSP antibody levels using IgG-based assays, but no standard assay is available to allow comparison of the different vaccines. Methods The validation of an anti-CSP repeat region enzyme-linked immunosorbent assay (ELISA) is described. This assay is based on the binding of serum antibodies to R32LR, a recombinant protein composed of the repeat region of P. falciparum CSP. In addition to the original recombinant R32LR, an easy to purify recombinant His-tagged R32LR protein has been constructed to be used as solid phase antigen in the assay. Also, hybridoma cell lines have been generated producing human anti-R32LR monoclonal antibodies to be used as a potential inexhaustible source of anti-CSP repeats standard, instead of a reference serum. Results The anti-CSP repeats ELISA was shown to be robust, specific and linear within the analytical range, and adequately fulfilled all validation criteria as defined in the ICH guidelines. Furthermore, the coefficient of variation for repeatability and intermediate precision did not exceed 23%. Non-interference was demonstrated for R32LR-binding sera, and the assay was shown to be stable over time. Conclusions This ELISA, specific for antibodies directed against the CSP repeat region, can be used as a standard assay for the determination of humoral immunogenicity in the development of any CSP-based P. falciparum malaria vaccine.
Collapse
|
49
|
Zeeshan M, Alam MT, Vinayak S, Bora H, Tyagi RK, Alam MS, Choudhary V, Mittra P, Lumb V, Bharti PK, Udhayakumar V, Singh N, Jain V, Singh PP, Sharma YD. Genetic variation in the Plasmodium falciparum circumsporozoite protein in India and its relevance to RTS,S malaria vaccine. PLoS One 2012; 7:e43430. [PMID: 22912873 PMCID: PMC3422267 DOI: 10.1371/journal.pone.0043430] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 07/20/2012] [Indexed: 11/19/2022] Open
Abstract
RTS,S is the most advanced malaria vaccine candidate, currently under phase-III clinical trials in Africa. This Plasmodium falciparum vaccine contains part of the central repeat region and the complete C-terminal T cell epitope region (Th2R and Th3R) of the circumsporozoite protein (CSP). Since naturally occurring polymorphisms at the vaccine candidate loci are critical determinants of the protective efficacy of the vaccines, it is imperative to investigate these polymorphisms in field isolates. In this study we have investigated the genetic diversity at the central repeat, C-terminal T cell epitope (Th2R and Th3R) and N-terminal T cell epitope regions of the CSP, in P. falciparum isolates from Madhya Pradesh state of India. These isolates were collected through a 5-year prospective study aimed to develop a well-characterized field-site for the future evaluation of malaria vaccine in India. Our results revealed that the central repeat (63 haplotypes, n = 161) and C-terminal Th2R/Th3R epitope (24 haplotypes, n = 179) regions were highly polymorphic, whereas N-terminal non-repeat region was less polymorphic (5 haplotypes, n = 161) in this population. We did not find any evidence of the role of positive natural selection in maintaining the genetic diversity at the Th2R/Th3R regions of CSP. Comparative analysis of the Th2R/Th3R sequences from this study to the global isolates (n = 1160) retrieved from the GenBank database revealed two important points. First, the majority of the sequences (∼61%, n = 179) from this study were identical to the Dd2/Indochina type, which is also the predominant Th2R/Th3R haplotype in Asia (∼59%, n = 974). Second, the Th2R/Th3R sequences in Asia, South America and Africa are geographically distinct with little allele sharing between continents. In conclusion, this study provides an insight on the existing polymorphisms in the CSP in a parasite population from India that could potentially influence the efficacy of RTS,S vaccine in this region.
Collapse
Affiliation(s)
- Mohammad Zeeshan
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Mohammad Tauqeer Alam
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Sumiti Vinayak
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Hema Bora
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Rupesh Kumar Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Mohd Shoeb Alam
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Vandana Choudhary
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Pooja Mittra
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Vanshika Lumb
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | | | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Neeru Singh
- Regional Medical Research Centre for Tribals, Jabalpur, Madhya Pradesh, India
| | - Vidhan Jain
- Regional Medical Research Centre for Tribals, Jabalpur, Madhya Pradesh, India
| | | | - Yagya Dutta Sharma
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
- * E-mail:
| |
Collapse
|
50
|
Navarro M, Castro W, Biot C. Bioorganometallic Compounds with Antimalarial Targets: Inhibiting Hemozoin Formation. Organometallics 2012. [DOI: 10.1021/om300296n] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Maribel Navarro
- School
of Chemical and Mathematical Sciences, Murdoch University, Western Australia 6150, Australia
| | - William Castro
- Lab. Quı́mica Bioinorgánica,
Centro de Quı́mica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas
1020-A, Venezuela
| | - Christophe Biot
- Unité
de Glycobiologie
Structurale et Fonctionnelle, UMR CNRS 8576, Université Lille 1, 59650 Villeneuve d’Ascq, France
| |
Collapse
|