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Billingsley PF, Richie TL, Abdulla S, Ondo'o Ayekaba M, Daubenberger CA, Garcia GA, Hoffman SL. A paradigm for Africa-centric vaccine development in Equatorial Guinea. Trends Parasitol 2024; 40:362-366. [PMID: 38582683 DOI: 10.1016/j.pt.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/26/2024] [Accepted: 03/12/2024] [Indexed: 04/08/2024]
Abstract
The Equatorial Guinea Malaria Vaccine Initiative (EGMVI) highlights how long-term African government and international energy industry investment, plus novel partnerships, can enable clinical development of vaccines in Africa, for Africa. We review achievements and challenges of this pioneering, award-winning, public-private partnership which offers a model for future Africa-centric clinical research and development (R&D).
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Affiliation(s)
| | - Thomas L Richie
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD 20850, USA
| | - Salim Abdulla
- Bagamoyo Research and Training Center, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Mitoha Ondo'o Ayekaba
- Ministry of Health and Social Welfare, Government of the Republic of Equatorial Guinea, Malabo, Bioko Norte, Equatorial Guinea
| | - Claudia A Daubenberger
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, 4123 Allschwil, Switzerland; University of Basel, Peterplatz 1, 4001 Basel, Switzerland
| | - Guíllermo A Garcia
- MCD Global Health, 8403 Colesville Rd, Suite 320, Silver Spring, MD 20910, USA
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2
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Jongo S, Church LP, Milando F, Qassim M, Schindler T, Rashid M, Tumbo A, Nyaulingo G, Bakari BM, Athuman Mbaga T, Mohamed L, Kassimu K, Simon BS, Mpina M, Zaidi I, Duffy PE, Swanson PA, Seder R, Herman JD, Mendu M, Zur Y, Alter G, KC N, Riyahi P, Abebe Y, Murshedkar T, James ER, Billingsley PF, Sim BKL, Richie TL, Daubenberger C, Abdulla S, Hoffman SL. Safety and protective efficacy of PfSPZ Vaccine administered to HIV-negative and -positive Tanzanian adults. J Clin Invest 2024; 134:e169060. [PMID: 38194272 PMCID: PMC10940097 DOI: 10.1172/jci169060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 12/20/2023] [Indexed: 01/10/2024] Open
Abstract
BACKGROUNDSanaria PfSPZ Vaccine, composed of attenuated Plasmodium falciparum (Pf) sporozoites (SPZ), protects against malaria. We conducted this clinical trial to assess the safety and efficacy of PfSPZ Vaccine in HIV-positive (HIV+) individuals, since the HIV-infection status of participants in mass vaccination programs may be unknown.METHODSThis randomized, double-blind, placebo-controlled trial enrolled 18- to 45-year-old HIV-negative (HIV-) and well-controlled HIV+ Tanzanians (HIV viral load <40 copies/mL, CD4 counts >500 cells/μL). Participants received 5 doses of PfSPZ Vaccine or normal saline (NS) over 28 days, followed by controlled human malaria infection (CHMI) 3 weeks later.RESULTSThere were no solicited adverse events in the 9 HIV- and 12 HIV+ participants. After CHMI, 6 of 6 NS controls, 1 of 5 HIV- vaccinees, and 4 of 4 HIV+ vaccinees were Pf positive by quantitative PCR (qPCR). After immunization, anti-Pf circumsporozoite protein (anti-PfCSP) (isotype and IgG subclass) and anti-PfSPZ antibodies, anti-PfSPZ CD4+ T cell responses, and Vδ2+ γδ CD3+ T cells were nonsignificantly higher in HIV- than in HIV+ vaccinees. Sera from HIV- vaccinees had significantly higher inhibition of PfSPZ invasion of hepatocytes in vitro and antibody-dependent complement deposition (ADCD) and Fcγ3B binding by anti-PfCSP and ADCD by anti-cell-traversal protein for ookinetes and SPZ (anti-PfCelTOS) antibodies.CONCLUSIONSPfSPZ Vaccine was safe and well tolerated in HIV+ vaccinees, but not protective. Vaccine efficacy was 80% in HIV- vaccinees (P = 0.012), whose sera had significantly higher inhibition of PfSPZ invasion of hepatocytes and enrichment of multifunctional PfCSP antibodies. A more potent PfSPZ vaccine or regimen is needed to protect those living with HIV against Pf infection in Africa.TRIAL REGISTRATIONClinicalTrials.gov NCT03420053.FUNDINGEquatorial Guinea Malaria Vaccine Initiative (EGMVI), made up of the Government of Equatorial Guinea Ministries of Mines and Hydrocarbons, and Health and Social Welfare, Marathon Equatorial Guinea Production Limited, Noble Energy, Atlantic Methanol Production Company, and EG LNG; Swiss government, through ESKAS scholarship grant no. 2016.0056; Intramural Research Program of the National Institute of Allergy and Infectious Diseases, NIH; NIH grant 1U01AI155354-01.
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Affiliation(s)
- Said Jongo
- Ifakara Health Institute (IHI), Bagamoyo, Tanzania
| | | | | | | | - Tobias Schindler
- Swiss Tropical Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Anneth Tumbo
- Ifakara Health Institute (IHI), Bagamoyo, Tanzania
- Swiss Tropical Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | | | | | | | | | | | | | - Maxmillian Mpina
- Ifakara Health Institute (IHI), Bagamoyo, Tanzania
- Swiss Tropical Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Irfan Zaidi
- Laboratory of Malaria Immunology and Vaccinology and
| | | | | | - Robert Seder
- Vaccine Research Center, NIH, Bethesda, Maryland, USA
| | - Jonathan D. Herman
- Division of Infectious Disease, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, USA
| | - Maanasa Mendu
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, USA
| | - Yonatan Zur
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, USA
| | - Galit Alter
- The Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, USA
| | - Natasha KC
- Sanaria Inc., Rockville, Maryland, USA
- Protein Potential LLC, Rockville, Maryland, USA
| | | | | | | | | | | | - B. Kim Lee Sim
- Sanaria Inc., Rockville, Maryland, USA
- Protein Potential LLC, Rockville, Maryland, USA
| | | | - Claudia Daubenberger
- Swiss Tropical Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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Challenger JD, van Beek SW, ter Heine R, van der Boor SC, Charles GD, Smit MJ, Ockenhouse C, Aponte JJ, McCall MBB, Jore MM, Churcher TS, Bousema T. Modeling the Impact of a Highly Potent Plasmodium falciparum Transmission-Blocking Monoclonal Antibody in Areas of Seasonal Malaria Transmission. J Infect Dis 2023; 228:212-223. [PMID: 37042518 PMCID: PMC10345482 DOI: 10.1093/infdis/jiad101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 02/06/2023] [Accepted: 04/11/2023] [Indexed: 04/13/2023] Open
Abstract
Transmission-blocking interventions can play an important role in combating malaria worldwide. Recently, a highly potent Plasmodium falciparum transmission-blocking monoclonal antibody (TB31F) was demonstrated to be safe and efficacious in malaria-naive volunteers. Here we predict the potential public health impact of large-scale implementation of TB31F alongside existing interventions. We developed a pharmaco-epidemiological model, tailored to 2 settings of differing transmission intensity with already established insecticide-treated nets and seasonal malaria chemoprevention interventions. Community-wide annual administration (at 80% coverage) of TB31F over a 3-year period was predicted to reduce clinical incidence by 54% (381 cases averted per 1000 people per year) in a high-transmission seasonal setting, and 74% (157 cases averted per 1000 people per year) in a low-transmission seasonal setting. Targeting school-aged children gave the largest reduction in terms of cases averted per dose. An annual administration of the transmission-blocking monoclonal antibody TB31F may be an effective intervention against malaria in seasonal malaria settings.
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Affiliation(s)
- Joseph D Challenger
- Medical Research Council Centre for Global Infections Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | | | - Rob ter Heine
- Department of Pharmacy, Radboud Institute for Health Sciences
| | - Saskia C van der Boor
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Giovanni D Charles
- Medical Research Council Centre for Global Infections Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Merel J Smit
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris Ockenhouse
- PATH Center for Vaccine Innovation and Access, Washington, District of Columbia, USA
| | - John J Aponte
- PATH Center for Vaccine Innovation and Access, Geneva, Switzerland
| | - Matthew B B McCall
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Matthijs M Jore
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thomas S Churcher
- Medical Research Council Centre for Global Infections Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
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4
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Effects of Age, Gender and Soil-Transmitted Helminth Infection on Prevalence of Plasmodium Infection among Population Living in Bata District, Equatorial Guinea. Trop Med Infect Dis 2023; 8:tropicalmed8030149. [PMID: 36977150 PMCID: PMC10059851 DOI: 10.3390/tropicalmed8030149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
Introduction: Malaria and soil-transmitted helminth (STH) co-infection is an important parasitic infection affecting populations in co-endemic countries including Equatorial Guinea. To date, the health impact of STH and malaria co-infection is inconclusive. The current study aimed to report the malaria and STH infection epidemiology in the continental region of Equatorial Guinea. Methods: We performed a cross-sectional study between October 2020 and January 2021 in the Bata district of Equatorial Guinea. Participants aged 1–9 years, 10–17 years and above 18 were recruited. Fresh venous blood was collected for malaria testing via mRDTs and light microscopy. Stool specimens were collected, and the Kato–Katz technique was used to detect the presence of Ascaris lumbricoides, Trichuris trichiura, hookworm spp. and intestinal Schistosoma eggs. Results: A total of 402 participants were included in this study. An amount of 44.3% of them lived in urban areas, and only 51.9% of them reported having bed nets. Malaria infections were detected in 34.8% of the participants, while 50% of malaria infections were reported in children aged 10–17 years. Females had a lower prevalence of malaria (28.8%) compared with males (41.7%). Children of 1–9 years carried more gametocytes compared with other age groups. An amount of 49.3% of the participants infected with T. trichiura had malaria parasites compared with those infected with A. lumbricoides (39.6%) or both (46.8%). Conclusions: The overlapping problem of STH and malaria is neglected in Bata. The current study forces the government and other stakeholders involved in the fight against malaria and STH to consider a combined control program strategy for both parasitic infections in Equatorial Guinea.
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Mpina M, Stabler TC, Schindler T, Raso J, Deal A, Acuche Pupu L, Nyakarungu E, Del Carmen Ovono Davis M, Urbano V, Mtoro A, Hamad A, Lopez MSA, Pasialo B, Eyang MAO, Rivas MR, Falla CC, García GA, Momo JC, Chuquiyauri R, Saverino E, Preston Church LW, Kim Lee Sim B, Manguire B, Tanner M, Maas C, Abdulla S, Billingsley PF, Hoffman SL, Jongo S, Richie TL, Daubenberger CA. Diagnostic performance and comparison of ultrasensitive and conventional rapid diagnostic test, thick blood smear and quantitative PCR for detection of low-density Plasmodium falciparum infections during a controlled human malaria infection study in Equatorial Guinea. Malar J 2022; 21:99. [PMID: 35331251 PMCID: PMC8943516 DOI: 10.1186/s12936-022-04103-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/23/2022] [Indexed: 12/02/2022] Open
Abstract
Background Progress towards malaria elimination has stagnated, partly because infections persisting at low parasite densities comprise a large reservoir contributing to ongoing malaria transmission and are difficult to detect. This study compared the performance of an ultrasensitive rapid diagnostic test (uRDT) designed to detect low density infections to a conventional RDT (cRDT), expert microscopy using Giemsa-stained thick blood smears (TBS), and quantitative polymerase chain reaction (qPCR) during a controlled human malaria infection (CHMI) study conducted in malaria exposed adults (NCT03590340). Methods Blood samples were collected from healthy Equatoguineans aged 18–35 years beginning on day 8 after CHMI with 3.2 × 103 cryopreserved, infectious Plasmodium falciparum sporozoites (PfSPZ Challenge, strain NF54) administered by direct venous inoculation. qPCR (18s ribosomal DNA), uRDT (Alere™ Malaria Ag P.f.), cRDT [Carestart Malaria Pf/PAN (PfHRP2/pLDH)], and TBS were performed daily until the volunteer became TBS positive and treatment was administered. qPCR was the reference for the presence of Plasmodium falciparum parasites. Results 279 samples were collected from 24 participants; 123 were positive by qPCR. TBS detected 24/123 (19.5% sensitivity [95% CI 13.1–27.8%]), uRDT 21/123 (17.1% sensitivity [95% CI 11.1–25.1%]), cRDT 10/123 (8.1% sensitivity [95% CI 4.2–14.8%]); all were 100% specific and did not detect any positive samples not detected by qPCR. TBS and uRDT were more sensitive than cRDT (TBS vs. cRDT p = 0.015; uRDT vs. cRDT p = 0.053), detecting parasitaemias as low as 3.7 parasites/µL (p/µL) (TBS and uRDT) compared to 5.6 p/µL (cRDT) based on TBS density measurements. TBS, uRDT and cRDT did not detect any of the 70/123 samples positive by qPCR below 5.86 p/µL, the qPCR density corresponding to 3.7 p/µL by TBS. The median prepatent periods in days (ranges) were 14.5 (10–20), 18.0 (15–28), 18.0 (15–20) and 18.0 (16–24) for qPCR, TBS, uRDT and cRDT, respectively; qPCR detected parasitaemia significantly earlier (3.5 days) than the other tests. Conclusions TBS and uRDT had similar sensitivities, both were more sensitive than cRDT, and neither matched qPCR for detecting low density parasitaemia. uRDT could be considered an alternative to TBS in selected applications, such as CHMI or field diagnosis, where qualitative, dichotomous results for malaria infection might be sufficient. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04103-y.
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Affiliation(s)
- Maxmillian Mpina
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Ifakara Health Institute, Ifakara, Tanzania.
| | - Thomas C Stabler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Tobias Schindler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Jose Raso
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Anna Deal
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Elizabeth Nyakarungu
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | | | - Vicente Urbano
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Ali Mtoro
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Ali Hamad
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Maria Silvia A Lopez
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Beltran Pasialo
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Marta Alene Owono Eyang
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Matilde Riloha Rivas
- Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | | | | | - Juan Carlos Momo
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Raul Chuquiyauri
- Medical Care Development International, Malabo, Equatorial Guinea.,Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | | | | | - B Kim Lee Sim
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | | | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Carl Maas
- Marathon EG production Ltd., Houston, USA
| | | | | | | | - Said Jongo
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Thomas L Richie
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Claudia A Daubenberger
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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6
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Yoboue CA, Hosch S, Donfack OT, Guirou EA, Nlavo BM, Ayekaba MO, Guerra C, Phiri WP, Garcia GA, Schindler T, Daubenberger CA. Characterising co-infections with Plasmodium spp., Mansonella perstans or Loa loa in asymptomatic children, adults and elderly people living on Bioko Island using nucleic acids extracted from malaria rapid diagnostic tests. PLoS Negl Trop Dis 2022; 16:e0009798. [PMID: 35100277 PMCID: PMC8830708 DOI: 10.1371/journal.pntd.0009798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 02/10/2022] [Accepted: 01/10/2022] [Indexed: 11/18/2022] Open
Abstract
Background Regular and comprehensive epidemiological surveys of the filarial nematodes Mansonella perstans and Loa loa in children, adolescents and adults living across Bioko Island, Equatorial Guinea are lacking. We aimed to demonstrate that blood retained on malaria rapid diagnostic tests, commonly deployed for malaria surveys, could be used as a source of nucleic acids for molecular based detection of M. perstans and L. loa. We wanted to determine the positivity rate and distribution of filarial nematodes across different age groups and geographical areas as well as to understand level of co-infections with malaria in an asymptomatic population. Methodology M. perstans, L. loa and Plasmodium spp. parasites were monitored by qPCR in a cross-sectional study using DNA extracted from a subset malaria rapid diagnostic tests (mRDTs) collected during the annual malaria indicator survey conducted on Bioko Island in 2018. Principal findings We identified DNA specific for the two filarial nematodes investigated among 8.2% (263) of the 3214 RDTs screened. Positivity rates of M. perstans and L. loa were 6.6% and 1.5%, respectively. M. perstans infection were more prominent in male (10.5%) compared to female (3.9%) survey participants. M. perstans parasite density and positivity rate was higher among older people and the population living in rural areas. The socio-economic status of participants strongly influenced the infection rate with people belonging to the lowest socio-economic quintile more than 3 and 5 times more likely to be L. loa and M. perstans infected, respectively. No increased risk of being co-infected with Plasmodium spp. parasites was observed among the different age groups. Conclusions/Significance We found otherwise asymptomatic individuals were infected with M. perstans and L. loa. Our study demonstrates that employing mRDTs probed with blood for malaria testing represents a promising, future tool to preserve and ship NAs at room temperature to laboratories for molecular, high-throughput diagnosis and genotyping of blood-dwelling nematode filarial infections. Using this approach, asymptomatic populations can be reached and surveyed for infectious diseases beyond malaria. Mansonella perstans and Loa loa are filarial nematodes that infect millions of people living in less developed areas, predominantly in sub-Saharan Africa. Both parasites are neglected among other filarial nematodes because both are regarded as causing mainly asymptomatic infections. The aim of this study was to explore the feasibility of using malaria rapid diagnostic tests (mRDTs) deployed during malaria surveys as a convenient sampling strategy for molecular surveillance of blood-dwelling filarial nematode infections. Our findings demonstrate the potential of mRDTs as a source of parasite DNA beyond malaria, providing an opportunity to expand current knowledge on the distribution and populations mostly affected by M. perstans and L. loa infections to Equatorial Guinea, located in Central-West Africa.
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Affiliation(s)
- Charlene Aya Yoboue
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Salome Hosch
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Etienne A. Guirou
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | | | | | - Carlos Guerra
- Medical Care Development International, Malabo, Equatorial Guinea
| | - Wonder P. Phiri
- Medical Care Development International, Malabo, Equatorial Guinea
| | | | - Tobias Schindler
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail: (TS); (CAD)
| | - Claudia A. Daubenberger
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail: (TS); (CAD)
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Greenwood B, Cairns M, Chaponda M, Chico RM, Dicko A, Ouedraogo JB, Phiri KS, Ter Kuile FO, Chandramohan D. Combining malaria vaccination with chemoprevention: a promising new approach to malaria control. Malar J 2021; 20:361. [PMID: 34488784 PMCID: PMC8419817 DOI: 10.1186/s12936-021-03888-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 08/20/2021] [Indexed: 11/13/2022] Open
Abstract
Malaria control has stalled in a number of African countries and novel approaches to malaria control are needed for these areas. The encouraging results of a recent trial conducted in young children in Burkina Faso and Mali in which a combination of the RTS,S/AS01E malaria vaccine and seasonal malaria chemoprevention led to a substantial reduction in clinical cases of malaria, severe malaria, and malaria deaths compared with the administration of either intervention given alone suggests that there may be other epidemiological/clinical situations in which a combination of malaria vaccination and chemoprevention could be beneficial. Some of these potential opportunities are considered in this paper. These include combining vaccination with intermittent preventive treatment of malaria in infants, with intermittent preventive treatment of malaria in pregnancy (through vaccination of women of child-bearing age before or during pregnancy), or with post-discharge malaria chemoprevention in the management of children recently admitted to hospital with severe anaemia. Other potential uses of the combination are prevention of malaria in children at particular risk from the adverse effects of clinical malaria, such as those with sickle cell disease, and during the final stages of a malaria elimination programme when vaccination could be combined with repeated rounds of mass drug administration. The combination of a pre-erythrocytic stage malaria vaccine with an effective chemopreventive regimen could make a valuable contribution to malaria control and elimination in a variety of clinical or epidemiological situations, and the potential of this approach to malaria control needs to be explored.
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Affiliation(s)
| | - Matthew Cairns
- London School of Hygiene and Tropical Medicine, London, UK
| | | | | | - Alassane Dicko
- Malaria Research and Training Centre, University of Science, Techniques and Technology of Bamako, Bamako, Mali
| | | | - Kamija S Phiri
- School of Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
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Citron DT, Guerra CA, García GA, Wu SL, Battle KE, Gibson HS, Smith DL. Quantifying malaria acquired during travel and its role in malaria elimination on Bioko Island. Malar J 2021; 20:359. [PMID: 34461902 PMCID: PMC8404405 DOI: 10.1186/s12936-021-03893-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/22/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria elimination is the goal for Bioko Island, Equatorial Guinea. Intensive interventions implemented since 2004 have reduced prevalence, but progress has stalled in recent years. A challenge for elimination has been malaria infections in residents acquired during travel to mainland Equatorial Guinea. The present article quantifies how off-island contributes to remaining malaria prevalence on Bioko Island, and investigates the potential role of a pre-erythrocytic vaccine in making further progress towards elimination. METHODS Malaria transmission on Bioko Island was simulated using a model calibrated based on data from the Malaria Indicator Surveys (MIS) from 2015 to 2018, including detailed travel histories and malaria positivity by rapid-diagnostic tests (RDTs), as well as geospatial estimates of malaria prevalence. Mosquito population density was adjusted to fit local transmission, conditional on importation rates under current levels of control and within-island mobility. The simulations were then used to evaluate the impact of two pre-erythrocytic vaccine distribution strategies: mass treat and vaccinate, and prophylactic vaccination for off-island travellers. Lastly, a sensitivity analysis was performed through an ensemble of simulations fit to the Bayesian joint posterior probability distribution of the geospatial prevalence estimates. RESULTS The simulations suggest that in Malabo, an urban city containing 80% of the population, there are some pockets of residual transmission, but a large proportion of infections are acquired off-island by travellers to the mainland. Outside of Malabo, prevalence was mainly attributable to local transmission. The uncertainty in the local transmission vs. importation is lowest within Malabo and highest outside. Using a pre-erythrocytic vaccine to protect travellers would have larger benefits than using the vaccine to protect residents of Bioko Island from local transmission. In simulations, mass treatment and vaccination had short-lived benefits, as malaria prevalence returned to current levels as the vaccine's efficacy waned. Prophylactic vaccination of travellers resulted in longer-lasting reductions in prevalence. These projections were robust to underlying uncertainty in prevalence estimates. CONCLUSIONS The modelled outcomes suggest that the volume of malaria cases imported from the mainland is a partial driver of continued endemic malaria on Bioko Island, and that continued elimination efforts on must account for human travel activity.
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Affiliation(s)
- Daniel T Citron
- Institute for Health Metrics and Evaluation, University of Washington, Population Health Building/Hans Rosling Center, 3980 15th Ave NE, Seattle, WA, 98195, USA.
| | - Carlos A Guerra
- Medical Care Development International, 8401 Colesville Road Suite 425, Silver Spring, MD, 20910, USA
| | - Guillermo A García
- Medical Care Development International, 8401 Colesville Road Suite 425, Silver Spring, MD, 20910, USA
| | - Sean L Wu
- Division of Epidemiology and Biostatistics, University of California, 2121 Berkeley Way, Berkeley, CA, 94720, USA
| | - Katherine E Battle
- Malaria Atlas Project, Telethon Kids Institute, Perth Children's Hospital, 15 Hospital Avenue, WA, 6009, Nedlands, Australia
- Institute for Disease Modeling, 500 5th Ave N, Seattle, WA, 98109, USA
| | - Harry S Gibson
- Malaria Atlas Project, Telethon Kids Institute, Perth Children's Hospital, 15 Hospital Avenue, WA, 6009, Nedlands, Australia
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Population Health Building/Hans Rosling Center, 3980 15th Ave NE, Seattle, WA, 98195, USA
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Nchama VUNN, Said AH, Mtoro A, Bidjimi GO, Owono MA, Maye ERM, Mangue MEO, Okomo GNN, Pasialo BEN, Ondo DM, Lopez MSA, Mochomuemue FL, Obono MO, Besaha JCM, Chuquiyauri R, Jongo SA, Kamaka K, Kibondo UA, Athuman T, Falla CC, Eyono JNM, Smith JM, García GA, Raso J, Nyakarungu E, Mpina M, Schindler T, Daubenberger C, Lemiale L, Billingsley PF, Sim BKL, Richie TL, Church LWP, Olotu A, Tanner M, Hoffman SL, Abdulla S. Incidence of Plasmodium falciparum malaria infection in 6-month to 45-year-olds on selected areas of Bioko Island, Equatorial Guinea. Malar J 2021; 20:322. [PMID: 34284778 PMCID: PMC8290541 DOI: 10.1186/s12936-021-03850-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/11/2021] [Indexed: 11/10/2022] Open
Abstract
Background Extensive malaria control measures have been implemented on Bioko Island, Equatorial Guinea over the past 16 years, reducing parasite prevalence and malaria-related morbidity and mortality, but without achieving elimination. Malaria vaccines offer hope for reducing the burden to zero. Three phase 1/2 studies have been conducted successfully on Bioko Island to evaluate the safety and efficacy of whole Plasmodium falciparum (Pf) sporozoite (SPZ) malaria vaccines. A large, pivotal trial of the safety and efficacy of the radiation-attenuated Sanaria® PfSPZ Vaccine against P. falciparum is planned for 2022. This study assessed the incidence of malaria at the phase 3 study site and characterized the influence of socio-demographic factors on the burden of malaria to guide trial design. Methods A cohort of 240 randomly selected individuals aged 6 months to 45 years from selected areas of North Bioko Province, Bioko Island, was followed for 24 weeks after clearance of parasitaemia. Assessment of clinical presentation consistent with malaria and thick blood smears were performed every 2 weeks. Incidence of first and multiple malaria infections per person-time of follow-up was estimated, compared between age groups, and examined for associated socio-demographic risk factors. Results There were 58 malaria infection episodes observed during the follow up period, including 47 first and 11 repeat infections. The incidence of malaria was 0.25 [95% CI (0.19, 0.32)] and of first malaria was 0.23 [95% CI (0.17, 0.30)] per person per 24 weeks (0.22 in 6–59-month-olds, 0.26 in 5–17-year-olds, 0.20 in 18–45-year-olds). Incidence of first malaria with symptoms was 0.13 [95% CI (0.09, 0.19)] per person per 24 weeks (0.16 in 6–59-month-olds, 0.10 in 5–17-year-olds, 0.11 in 18–45-year-olds). Multivariate assessment showed that study area, gender, malaria positivity at screening, and household socioeconomic status independently predicted the observed incidence of malaria. Conclusion Despite intensive malaria control efforts on Bioko Island, local transmission remains and is spread evenly throughout age groups. These incidence rates indicate moderate malaria transmission which may be sufficient to support future larger trials of PfSPZ Vaccine. The long-term goal is to conduct mass vaccination programmes to halt transmission and eliminate P. falciparum malaria.
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Affiliation(s)
- Vicente Urbano Nsue Ndong Nchama
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Ali Hamad Said
- Medical Care Development International (MCDI), Silver Spring, USA. .,Ifakara Health Institute, Dar es Salaam, Tanzania.
| | - Ali Mtoro
- Medical Care Development International (MCDI), Silver Spring, USA.,Ifakara Health Institute, Dar es Salaam, Tanzania
| | - Gertrudis Owono Bidjimi
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Marta Alene Owono
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Escolastica Raquel Mansogo Maye
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Martin Eka Ondo Mangue
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Genaro Nsue Nguema Okomo
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Beltran Ekua Ntutumu Pasialo
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Dolores Mbang Ondo
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Maria-Silvia Angue Lopez
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Fortunata Lobede Mochomuemue
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Mariano Obiang Obono
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Juan Carlos Momo Besaha
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Raul Chuquiyauri
- Medical Care Development International (MCDI), Silver Spring, USA.,Sanaria Inc., Rockville, USA
| | | | - Kassim Kamaka
- Medical Care Development International (MCDI), Silver Spring, USA.,Ifakara Health Institute, Dar es Salaam, Tanzania
| | | | | | | | | | | | | | - José Raso
- Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW), Malabo, Equatorial Guinea.,Medical Care Development International (MCDI), Silver Spring, USA
| | - Elizabeth Nyakarungu
- Medical Care Development International (MCDI), Silver Spring, USA.,Ifakara Health Institute, Dar es Salaam, Tanzania
| | - Maxmillian Mpina
- Ifakara Health Institute, Dar es Salaam, Tanzania.,Swiss Tropical and Public Health Institute (Swiss TPH), Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Tobias Schindler
- Swiss Tropical and Public Health Institute (Swiss TPH), Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Claudia Daubenberger
- Swiss Tropical and Public Health Institute (Swiss TPH), Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | | | | | | | | | - Ally Olotu
- Medical Care Development International (MCDI), Silver Spring, USA.,Ifakara Health Institute, Dar es Salaam, Tanzania
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute (Swiss TPH), Basel, Switzerland.,University of Basel, Basel, Switzerland
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Clustering of subpatent infections in households with asymptomatic rapid diagnostic test-positive cases in Bioko Island, Equatorial Guinea independent of travel to regions of higher malaria endemicity: a cross-sectional study. Malar J 2021; 20:313. [PMID: 34247643 PMCID: PMC8274032 DOI: 10.1186/s12936-021-03844-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 07/03/2021] [Indexed: 11/27/2022] Open
Abstract
Background Prevalence of falciparum malaria on Bioko Island remains high despite sustained, intensive control. Progress may be hindered by high proportions of subpatent infections that are not detected by rapid diagnostic tests (RDT) but contribute to onward transmission, and by imported infections. Better understanding of the relationship between subpatent infections and RDT-detected infections, and whether this relationship is different from imported versus locally acquired infections, is imperative to better understand the sources of infection and mechanisms of transmission to tailor more effective interventions. Methods Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was performed on a sub-set of samples from the 2015 Malaria Indicator Survey to identify subpatent infections. Households with RDT(+) individuals were matched 1:4 with households with no RDT(+) individuals. The association between living in a household with an RDT(+) individual and having a subpatent infection was evaluated using multivariate hierarchical logistic regression models with inverse probability weights for selection. To evaluate possible modification of the association by potential importation of the RDT(+) case, the analysis was repeated among strata of matched sets based on the reported eight-week travel history of the RDT(+) individual(s). Results There were 142 subpatent infections detected in 1,400 individuals (10.0%). The prevalence of subpatent infections was higher in households with versus without an RDT(+) individual (15.0 vs 9.1%). The adjusted prevalence odds of subpatent infection were 2.59-fold greater (95% CI: 1.31, 5.09) for those in a household with an RDT(+) individual compared to individuals in a household without RDT(+) individuals. When stratifying by travel history of the RDT(+) individual, the association between subpatent infections and RDT(+) infections was stronger in the strata in which the RDT(+) individual(s) had not recently travelled (adjusted prevalence odds ratio (aPOR) 2.95; 95% CI:1.17, 7.41), and attenuated in the strata in which recent travel was reported (aPOR 1.76; 95% CI: 0.54, 5.67). Conclusions There is clustering of subpatent infections around RDT(+) individual(s) when both imported and local infection are suspected. Future control strategies that aim to treat whole households in which an RDT(+) individual is found may target a substantial portion of infections that would otherwise not be detected. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03844-6.
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Billingsley PF, George KI, Eappen AG, Harrell RA, Alford R, Li T, Chakravarty S, Sim BKL, Hoffman SL, O'Brochta DA. Transient knockdown of Anopheles stephensi LRIM1 using RNAi increases Plasmodium falciparum sporozoite salivary gland infections. Malar J 2021; 20:284. [PMID: 34174879 PMCID: PMC8235909 DOI: 10.1186/s12936-021-03818-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/15/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum (Pf) sporozoites (PfSPZ) can be administered as a highly protective vaccine conferring the highest protection seen to date. Sanaria® PfSPZ vaccines are produced using aseptically reared Anopheles stephensi mosquitoes. The bionomics of sporogonic development of P. falciparum in A. stephensi to fully mature salivary gland PfSPZ is thought to be modulated by several components of the mosquito innate immune system. In order to increase salivary gland PfSPZ infections in A. stephensi and thereby increase vaccine production efficiency, a gene knock down approach was used to investigate the activity of the immune deficiency (IMD) signaling pathway downstream effector leucine-rich repeat immune molecule 1 (LRIM1), an antagonist to Plasmodium development. METHODS Expression of LRIM1 in A. stephensi was reduced following injection of double stranded (ds) RNA into mosquitoes. By combining the Gal4/UAS bipartite system with in vivo expression of short hairpin (sh) RNA coding for LRIM1 reduced expression of LRIM1 was targeted in the midgut, fat body, and salivary glands. RT-qPCR was used to demonstrate fold-changes in gene expression in three transgenic crosses and the effects on P. falciparum infections determined in mosquitoes showing the greatest reduction in LRIM1 expression. RESULTS LRIM1 expression could be reduced, but not completely silenced, by expression of LRIM1 dsRNA. Infections of P. falciparum oocysts and PfSPZ were consistently and significantly higher in transgenic mosquitoes than wild type controls, with increases in PfSPZ ranging from 2.5- to tenfold. CONCLUSIONS Plasmodium falciparum infections in A. stephensi can be increased following reduced expression of LRIM1. These data provide the springboard for more precise knockout of LRIM1 for the eventual incorporation of immune-compromised A. stephensi into manufacturing of Sanaria's PfSPZ products.
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Affiliation(s)
- Peter F Billingsley
- Sanaria Inc, Suite A209, 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Kasim I George
- Institute for Bioscience and Biotechnology Research and Department of Entomology, University of Maryland, Gudelsky Drive, Rockville, MD, 20850, USA
- Qiagen Inc, 19300 Germantown Road, Germantown, MD, 20874, USA
| | - Abraham G Eappen
- Sanaria Inc, Suite A209, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Robert A Harrell
- Institute for Bioscience and Biotechnology Research and Department of Entomology, University of Maryland, Gudelsky Drive, Rockville, MD, 20850, USA
- Insect Transformation Facility, Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - Robert Alford
- Institute for Bioscience and Biotechnology Research and Department of Entomology, University of Maryland, Gudelsky Drive, Rockville, MD, 20850, USA
- Insect Transformation Facility, Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - Tao Li
- Sanaria Inc, Suite A209, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Sumana Chakravarty
- Sanaria Inc, Suite A209, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - B Kim Lee Sim
- Sanaria Inc, Suite A209, 9800 Medical Center Drive, Rockville, MD, 20850, USA
- Protein Potential, Suite A209, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Stephen L Hoffman
- Sanaria Inc, Suite A209, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - David A O'Brochta
- Institute for Bioscience and Biotechnology Research and Department of Entomology, University of Maryland, Gudelsky Drive, Rockville, MD, 20850, USA
- Foundation for the National Institutes of Health, 11400 Rockville Pike, Suite 600, North Bethesda, MD, 20852, USA
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