Publications by authors named "Alfred B Tiono"

Background: In malaria vaccine clinical trials, immune responses after vaccination may be compromised due to immunosuppression caused by concurrent Plasmodium falciparum infection. This has a direct effect on the protective efficacy of the vaccine being evaluated. Therefore, parasite clearance prior to vaccination is being considered.

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Introduction: ProC6C is a multi-stage malaria vaccine which includes Circumsporozoite Protein (PfCSP), Pfs48/45 and Pfs230 sequences, designed to elicit functional antibodies that prevent sporozoite invasion of human hepatocytes (PfCSP) and parasite development in mosquitoes (Pfs48/45 and Pfs230). ProC6C formulated on Alhydrogel was evaluated in combination with Matrix-M in a Phase 1 trial in Burkina Faso. The PfCSP antibody responses were assessed for magnitude, specificity, avidity and functionality.

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The aim of this study was to explore molecular measures of malaria burden (FOI and MOI) in the context of seasonal malaria chemoprevention. We analyzed malaria cases collected as part of a longitudinal cohort study. The cohort included -negative children aged 1.

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Background: The majority of Plasmodium spp infections in endemic countries are asymptomatic and a source of onward transmission to mosquitoes. We aimed to examine whether Plasmodium falciparum transmission and malaria burden could be reduced by improving early detection and treatment of infections with active screening approaches.

Methods: In this 18-month cluster randomised study in Sapone, Burkina Faso, households were enrolled and randomly assigned (1:1:1) to one of three groups: group 1 (control) received standard of care only, group 2 received active weekly, at home, fever screening by a community health worker regardless of symptoms, participants with a fever received a rapid diagnostic test (RDT) and treatment if RDT positive, and group 3 received active weekly fever screening (as in group 2) plus a monthly RDT regardless of symptoms, and treatment if RDT positive.

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It is currently unknown whether all -infected mosquitoes are equally infectious. We assessed sporogonic development using cultured gametocytes in the Netherlands and naturally circulating strains in Burkina Faso. We quantified the number of sporozoites expelled into artificial skin in relation to intact oocysts, ruptured oocysts, and residual salivary gland sporozoites.

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Introduction: Seasonal malaria chemoprevention (SMC) involves repeated administrations of sulfadoxine-pyrimethamine plus amodiaquine to children below the age of 5 years during the peak transmission season in areas of seasonal malaria transmission. While highly impactful in reducing malaria burden in controlled research settings, the impact of SMC on infection prevalence is moderate in real-life settings. It remains unclear what drives this efficacy decay.

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Information on the dynamics and decline/persistence of antibody titres is important in vaccine development. A recent vaccine trial in malaria-exposed, healthy African adults and children living in a malaria hyperendemic and seasonal area (Ouagadougou, Burkina Faso) was the first study in which BK-SE36/CpG was administered to different age groups. In 5- to 10-year-old children, the risk of malaria infection was markedly lower in the BK-SE36/CpG arm compared to the control arm.

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BACKGROUNDMalaria transmission-blocking vaccines aim to interrupt the transmission of malaria from one person to another.METHODSThe candidates R0.6C and ProC6C share the 6C domain of the Plasmodium falciparum sexual-stage antigen Pfs48/45.

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The estimates of enterotoxigenic (ETEC) and burden in developing countries are limited by the lack of rapid, accessible, and sensitive diagnostics and surveillance tools. We used a "Rapid LAMP based Diagnostic Test (RLDT)" to detect ETEC and in diarrheal and non-diarrheal stool samples from a 12-month longitudinal cohort of children under five years of age in a peri-urban area of Ouagadougou in Burkina Faso (West Africa). To allow comparison with the RLDT- results, conventional culture methods were used to identify strains in the stool samples.

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Article Synopsis
  • BK-SE36/CpG is a malaria vaccine candidate that was tested for safety and immune response in healthy, malaria-exposed participants in Burkina Faso.
  • In a clinical trial involving 135 participants across different age groups, the vaccine was well tolerated with no severe adverse events linked to it, although mild to moderate side effects like pain and fever were noted.
  • The vaccine elicited stronger immune responses in younger age groups, with participants showing higher antibody levels after the final dose compared to earlier doses.
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Continuous monitoring of malaria epidemiology is needed in malaria-endemic settings to inform malaria control and elimination strategies. This study aimed to compare the malariometric indices between the under-fives and school-age children. We surveyed children aged 1.

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We assessed anti-Vi IgG/IgA responses to typhoid conjugate vaccine (TCV) in children enrolled in a double-blind randomized controlled, phase 2 trial in Burkina Faso. Anti-Vi IgG seroconversion and anti-Vi IgA titers were higher in TCV than control recipients at 30-35 months post-vaccination. TCV induces durable immunity in Burkinabe children vaccinated at 15 months.

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Article Synopsis
  • * The study developed a testing pipeline using direct membrane feeding assays (DMFA) to assess the effectiveness of various marketed and experimental drugs against gametocytes from field isolates, focusing on their transmission-blocking capabilities.
  • * Results showed that several compounds, particularly methylene-blue, MMV693183, DDD107498, atovaquone, and P218, demonstrated strong transmission-blocking activity, establishing a robust method for future evaluations of antimalarial drug effectiveness in blocking transmission.
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Disease control programs are needed to identify the breeding sites of mosquitoes, which transmit malaria and other diseases, in order to target interventions and identify environmental risk factors. The increasing availability of very-high-resolution drone data provides new opportunities to find and characterize these vector breeding sites. Within this study, drone images from two malaria-endemic regions in Burkina Faso and Côte d'Ivoire were assembled and labeled using open-source tools.

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(1) Background: Effective malaria case management relies on World Health Organization (WHO) recommended artemisinin-based combination therapies (ACTs), but partial resistance to artemisinin has emerged and is spreading, threatening malaria control and elimination efforts. The strategy of deploying multiple first-line therapies (MFT) may help mitigate this threat and extend the therapeutic life of current ACTs. (2) Methods: A district-wide pilot quasi-experimental study was conducted, deploying three different ACTs at the public health facility (PHF) level for uncomplicated malaria treatment from December 2019 to December 2020 in the health district (HD) of Kaya, Burkina Faso.

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Background: A vaccine targeting the erythrocyte stages of could play a role in preventing clinical disease. BK-SE36 is a promising malaria vaccine candidate that has shown a good safety profile and immunological responses during field evaluations. It was observed that repeated natural infections could result in immune tolerance against SE36 molecule.

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Background: In the current context of tailoring interventions to maximize impact, it is important that current data of clinical epidemiology guide public health programmes and health workers in the management of severe disease. This study aimed at describing the burden of severe malaria at hospital level in two areas with distinct malaria transmission intensity.

Methods: A hospital-based surveillance was established in two regional hospitals located in two areas exposed to different malaria transmission.

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BK-SE36, based on serine repeat antigen 5 (SERA5), is a blood-stage malaria vaccine candidate currently being evaluated in clinical trials. Phase 1 trials in Uganda and Burkina Faso have demonstrated promising safety and immunogenicity profiles. However, the genetic diversity of in Africa and the role of allele/variant-specific immunity remain a major concern.

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Unlabelled: The experimental malaria vaccine ChAd63 MVA ME-TRAP previously showed protective efficacy against infection in Phase IIa sporozoite challenge studies in adults in the United Kingdom and in a Phase IIb field efficacy trial in Kenyan adults. However, it failed to demonstrate efficacy in a phase IIb trial in 5-17 month-old children in an area of high malaria transmission in Burkina Faso. This secondary analysis investigated whether exposure to malaria or nutritional status might be associated with reduced responses to vaccination in this cohort.

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A highly effective malaria vaccine remains elusive despite decades of research. sporozoite vaccine (PfSPZ Vaccine), a metabolically active, nonreplicating, whole parasite vaccine demonstrated safety and vaccine efficacy (VE) against endemic for 6 months in Malian adults receiving a five-dose regimen. Safety, immunogenicity, and VE of a three-dose regimen were assessed in adults in Balonghin, Burkina Faso in a two-component study: an open-label dose escalation trial with 32 participants followed by a double-blind, randomized, placebo-controlled trial (RCT) with 80 participants randomized to receive three doses of 2.

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Background: A blood-stage vaccine targeting the erythrocytic-stages of the malaria parasite could play a role to protect against clinical disease. Antibodies against the serine repeat antigen 5 (SE47 and SE36 domains) correlate well with the absence of clinical symptoms in sero-epidemiological studies. A previous phase Ib trial of the recombinant SE36 antigen formulated with aluminum hydroxyl gel (BK-SE36) was promising.

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Article Synopsis
  • * A systematic review and meta-analysis of 20 studies involving over 6,400 participants assessed the impact of primaquine on hemoglobin levels and adverse effects, focusing on those with and without G6PD deficiency.
  • * Results showed no significant hemoglobin reduction in G6PD-normal individuals, but a notable drop in G6PD-deficient patients; serious adverse events were rare, with only one report of a blood transfusion and no deaths linked to primaquine.
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Article Synopsis
  • Seasonal Malaria Chemoprevention (SMC), which uses a combination of amodiaquine and sulfadoxine-pyrimethamine, is endorsed by the WHO as a method to reduce malaria cases in areas with intense seasonal transmission, especially among children under 5.
  • Despite its potential benefits, there are ongoing debates around its effectiveness due to issues like developing malaria-specific immunity, growing resistance to antimalarial drugs, and limited delivery to children.
  • The review highlights the need to evaluate the SMC's impact on malaria morbidity and resistance, and aims to identify factors affecting the success of the strategy to enhance malaria control in affected regions.
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