2024 |
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Journal Articles |
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Nora Schmit, Hillary M. Topazian, H. Magloire Natama, Duncan Bellamy, Ousmane Traoré, M. Athanase Somé, Toussaint Rouamba, Marc Christian Tahita, Massa Achille Bonko, Aboubakary Sourabié, Hermann Sorgho, Lisa Stockdale, Samuel Provstgaard-Morys, Jeremy Aboagye, Danielle Woods, Katerina Rapi, Mehreen S. Datoo, Fernando Ramos Lopez, Giovanni D. Charles, Kelly McCain, Jean Bosco Ouedraogo, Mainga Hamaluba, Ally Olotu, Alassane Dicko, Halidou Tinto, Adrian V. S. Hill, Katie J. Ewer, Azra C. Ghani, Peter Winskill The public health impact and cost-effectiveness of the R21/Matrix-M malaria vaccine: a mathematical modelling study Journal Article In: The Lancet. Infectious diseases, vol. 24, iss. 5, pp. 465-475, 2024, ISSN: 1474-4457. Abstract | BibTeX | Tags: Antibodies, Burkina Faso / epidemiology, Child, Cost-Benefit Analysis*, Falciparum* / economics, Falciparum* / epidemiology, Falciparum* / prevention & control, Female, Hillary M Topazian, Humans, Infant, Malaria, Malaria Vaccines* / administration & dosage, Malaria Vaccines* / economics, Malaria Vaccines* / immunology, Male, MEDLINE, Models, National Center for Biotechnology Information, National Institutes of Health, National Library of Medicine, NCBI, NIH, NLM, Non-U.S. Gov't, Nora Schmit, Peter Winskill, Plasmodium falciparum / immunology, pmid:38342107, Preschool, Protozoan / blood, Protozoan Proteins / immunology, Public Health* / economics, PubMed Abstract, Research Support, Theoretical*, Vaccine Efficacy | Links: @article{Schmit2024, Background: The R21/Matrix-M vaccine has demonstrated high efficacy against Plasmodium falciparum clinical malaria in children in sub-Saharan Africa. Using trial data, we aimed to estimate the public health impact and cost-effectiveness of vaccine introduction across sub-Saharan Africa. Methods: We fitted a semi-mechanistic model of the relationship between anti-circumsporozoite protein antibody titres and vaccine efficacy to data from 3 years of follow-up in the phase 2b trial of R21/Matrix-M in Nanoro, Burkina Faso. We validated the model by comparing predicted vaccine efficacy to that observed over 12–18 months in the phase 3 trial. Integrating this framework within a mathematical transmission model, we estimated the cases, malaria deaths, and disability-adjusted life-years (DALYs) averted and cost-effectiveness over a 15-year time horizon across a range of transmission settings in sub-Saharan Africa. Cost-effectiveness was estimated incorporating the cost of vaccine introduction (dose, consumables, and delivery) relative to existing interventions at baseline. We report estimates at a median of 20% parasite prevalence in children aged 2–10 years (PfPR2–10) and ranges from 3% to 65% PfPR2–10. Findings: Anti-circumsporozoite protein antibody titres were found to satisfy the criteria for a surrogate of protection for vaccine efficacy against clinical malaria. Age-based implementation of a four-dose regimen of R21/Matrix-M vaccine was estimated to avert 181 825 (range 38 815–333 491) clinical cases per 100 000 fully vaccinated children in perennial settings and 202 017 (29 868–405 702) clinical cases per 100 000 fully vaccinated children in seasonal settings. Similar estimates were obtained for seasonal or hybrid implementation. Under an assumed vaccine dose price of US$3, the incremental cost per clinical case averted was $7 (range 4–48) in perennial settings and $6 (3–63) in seasonal settings and the incremental cost per DALY averted was $34 (29–139) in perennial settings and $30 (22–172) in seasonal settings, with lower cost-effectiveness ratios in settings with higher PfPR2–10. Interpretation: Introduction of the R21/Matrix-M malaria vaccine could have a substantial public health benefit across sub-Saharan Africa. Funding: The Wellcome Trust, the Bill & Melinda Gates Foundation, the UK Medical Research Council, the European and Developing Countries Clinical Trials Partnership 2 and 3, the NIHR Oxford Biomedical Research Centre, and the Serum Institute of India, Open Philanthropy. | |||
Irene Molina–de Fuente, Marc Christian Tahita, Kabore Bérenger, Thuy Huong Ta Tang, Luz García, Vicenta González, Agustín Benito, Judith M. Hübschen, Halidou Tinto, Pedro Berzosa Malaria diagnosis challenges and pfhrp2 and pfhrp3 gene deletions using pregnant women as sentinel population in Nanoro region, Burkina Faso Journal Article In: Pathogens and global health, vol. 118, iss. 6, 2024, ISSN: 2047-7732. Abstract | BibTeX | Tags: Adolescent, Adult, Antigens, Burkina Faso / epidemiology, Diagnostic Tests, doi:10.1080/20477724.2024.2388489, Falciparum* / diagnosis, Falciparum* / epidemiology, Falciparum* / parasitology, Female, Gene Deletion*, Humans, Irene Molina-de la Fuente, Malaria, Marc Christian Tahita, MEDLINE, Microscopy, National Center for Biotechnology Information, National Institutes of Health, National Library of Medicine, NCBI, NIH, NLM, Non-U.S. Gov't, Parasitic / diagnosis, Parasitic / epidemiology, Pedro Berzosa, Plasmodium falciparum* / genetics, Plasmodium falciparum* / isolation & purification, PMC11441055, pmid:39140699, Pregnancy, Pregnancy Complications, Protozoan Proteins* / genetics, Protozoan* / genetics, PubMed Abstract, Research Support, Routine* / methods, Sensitivity and Specificity*, Young Adult | Links: @article{nokey, Malaria in pregnancy causes adverse consequences and prompt and accurate diagnosis is essential for case management. In malaria endemic countries, diagnosis is mainly based on rapid diagnostic tests (RDT) and microscopy. However, increasing reports of false negatives caused by low parasitemia and pfhrp2/3 deletions raise concerns about HRP2-based RDT usefulness. This study aimed to assess RDT and microscopy performance and to describe pfhrp2/3 deletions in a cohort of 418 pregnant women in Burkina Faso. Malaria was diagnosed using RDT and microscopy and blood samples were collected during antenatal care visits. Diagnostic results were compared to PCR as gold standard. Pfhrp2 and pfhrp3 deletions were characterized for patients with confirmed P. falciparum infection. RDT had better sensitivity (76%) but lower specificity (83%) than microscopy (sensitivity = 57%; specificity = 98%). Low parasitemia (<150 parasites/µL), especially in multigravidae, was the principal factor causing false negatives by both methods. Moreover, pfhrp2 deletion frequency among overall false negatives by RDT was 21.43%. Higher frequency of deletions was found among all samples, independently of RDT result, for example around 2% of samples had double deletions meaning that the majority of deletions had no effect on RDT testing. Finally, it was found higher pfhrp2 deletion in women with lower uterine height during the first trimester. Wider and National surveillance study of deletions is recommended among pregnant women and in Burkina Faso. | |||
2023 |
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Journal Articles |
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Holger W. Unger, Anastasia Jessica Hadiprodjo, Julie R. Gutman, Valerie Briand, Nadine Fievet, Innocent Valea, Halidou Tinto, Umberto D’Alessandro, Sarah H. Landis, Feiko Ter Kuile, Peter Ouma, Martina Oneko, Victor Mwapasa, Laurence Slutsker, Dianne J. Terlouw, Simon Kariuki, John Ayisi, Bernard Nahlen, Meghna Desai, Mwayi Madanitsa, Linda Kalilani-Phiri, Per Ashorn, Kenneth Maleta, Antoinette Tshefu-Kitoto, Ivo Mueller, Danielle Stanisic, Jordan Cates, Anna Maria Van Eijk, Maria Ome-Kaius, Elizabeth H. Aitken, Stephen J. Rogerson Fetal sex and risk of pregnancy-associated malaria in Plasmodium falciparum-endemic regions: a meta-analysis Journal Article In: Scientific reports, vol. 13, iss. 1, 2023, ISSN: 2045-2322. Abstract | BibTeX | Tags: Anastasia Jessica Hadiprodjo, doi:10.1038/s41598-023-37431-3, Extramural, Falciparum* / complications, Falciparum* / epidemiology, Female, Holger W Unger, Humans, Infant, Low Birth Weight, Malaria, Malaria* / complications, Malaria* / epidemiology, MEDLINE, Meta-Analysis, N.I.H., National Center for Biotechnology Information, National Institutes of Health, National Library of Medicine, NCBI, Newborn, NIH, NLM, Non-U.S. Gov't, placenta, Plasmodium falciparum, PMC10293221, pmid:37365258, Pregnancy, PubMed Abstract, Research Support, Stephen J Rogerson, Stillbirth | Links: @article{Unger2023, In areas of moderate to intense Plasmodium falciparum transmission, malaria in pregnancy remains a significant cause of low birth weight, stillbirth, and severe anaemia. Previously, fetal sex has been identified to modify the risks of maternal asthma, pre-eclampsia, and gestational diabetes. One study demonstrated increased risk of placental malaria in women carrying a female fetus. We investigated the association between fetal sex and malaria in pregnancy in 11 pregnancy studies conducted in sub-Saharan African countries and Papua New Guinea through meta-analysis using log binomial regression fitted to a random-effects model. Malaria infection during pregnancy and delivery was assessed using light microscopy, polymerase chain reaction, and histology. Five studies were observational studies and six were randomised controlled trials. Studies varied in terms of gravidity, gestational age at antenatal enrolment and bed net use. Presence of a female fetus was associated with malaria infection at enrolment by light microscopy (risk ratio 1.14 [95% confidence interval 1.04, 1.24]; P = 0.003; n = 11,729). Fetal sex did not associate with malaria infection when other time points or diagnostic methods were used. There is limited evidence that fetal sex influences the risk of malaria infection in pregnancy. | |||
Peter J. Neyer, Bérenger Kaboré, Christos T. Nakas, Britta Hartmann, Annelies Post, Salou Diallo, Halidou Tinto, Angelika Hammerer-Lercher, Carlo R. Largiadèr, Andre J. Ven, Andreas R. Huber Exploring the host factors affecting asymptomatic Plasmodium falciparum infection: insights from a rural Burkina Faso study Journal Article In: Malaria journal, vol. 22, iss. 1, 2023, ISSN: 1475-2875. Abstract | BibTeX | Tags: Adolescent, Andreas R Huber, Asymptomatic Infections / epidemiology, Bérenger Kaboré, Burkina Faso / epidemiology, Child, doi:10.1186/s12936-023-04686-0, Falciparum* / epidemiology, hemoglobin, Hepcidins*, Humans, Malaria, MEDLINE, National Center for Biotechnology Information, National Institutes of Health, National Library of Medicine, NCBI, NIH, NLM, Peter J Neyer, Plasmodium falciparum / genetics, PMC10474782, pmid:37658365, PubMed Abstract, Sickle | Links: @article{Neyer2023, Background: Asymptomatic Plasmodium falciparum parasitaemia forms a reservoir for the transmission of malaria disease in West Africa. Certain haemoglobin variants are known to protect against severe malaria infection. However, data on the potential roles of haemoglobin variants and nongenetic factors in asymptomatic malaria infection is scarce and controversial. Therefore, this study investigated the associations of iron homeostasis, inflammation, nutrition, and haemoglobin mutations with parasitaemia in an asymptomatic cohort from a P. falciparum-endemic region during the high transmission season. Methods: A sub-study population of 688 asymptomatic individuals (predominantly children and adolescents under 15 years | |||
Japhet Kabalu Tshiongo, Flory Luzolo, Melissa Kabena, Lise Kuseke, Moussa Djimde, Patrick Mitashi, Crispin Lumbala, Kassoum Kayentao, Sandra Menting, Petra F. Mens, Henk D. F. H. Schallig, Pascal Lutumba, Halidou Tinto, Hypolite Muhindo Mavoko, Vivi Maketa Performance of ultra-sensitive malaria rapid diagnostic test to detect Plasmodium falciparum infection in pregnant women in Kinshasa, the Democratic Republic of the Congo Journal Article In: Malaria journal, vol. 22, iss. 1, 2023, ISSN: 1475-2875. Abstract | BibTeX | Tags: Antigens, Democratic Republic of the Congo, Diagnostic Tests, doi:10.1186/s12936-023-04749-2, Falciparum* / epidemiology, Female, Flory Luzolo, Humans, Japhet Kabalu Tshiongo, Malaria, Malaria*, MEDLINE, National Center for Biotechnology Information, National Institutes of Health, National Library of Medicine, NCBI, NIH, NLM, Plasmodium falciparum, PMC10594769, pmid:37872634, Pregnancy, Pregnant Women, Protozoan, PubMed Abstract, Rapid diagnostic tests, Routine / methods, Sensitivity and Specificity, Vivi Maketa | Links: @article{nokey, Background: Low peripheral parasitaemia caused by sequestration of Plasmodium falciparum in the placenta hampers the diagnosis of malaria in pregnant women, leading to microscopy or conventional rapid diagnostic tests (RDTs) false-negative results. Although mainly asymptomatic, maternal malaria remains harmful to pregnant women and their offspring in endemic settings and must be adequately diagnosed. Ultra-sensitive RDTs (uRDTs) are thought to be more sensitive than RDTs, and their diagnostic performance was assessed in the current study in pregnant women living in Kinshasa, a stable malaria transmission area in the Democratic Republic of the Congo. Methods: To assess and compare the diagnostic performances of both RDTs and uRDTs, 497 peripheral blood samples were tested using microscopy and quantitative polymerase chain reaction (qPCR) as the index and the reference tests, respectively. The agreement between the different diagnostic tests assessed was estimated by Cohen's Kappa test. Results: The median parasite density by qPCR was 292 p/μL of blood [IQR (49.7–1137)]. Using qPCR as the reference diagnostic test, the sensitivities of microscopy, RDT and uRDT were respectively [55.7% (95% CI 47.6–63.6)], [81.7% (95%CI 74.7–87.3)] and [88% (95% CI 81.9–92.6)]. The specificities of the tests were calculated at 98.5% (95% CI 96.6–99.5), 95.2% (95% CI 92.5–97.2) and 94.4% (95% CI 91.4–96.6) for microscopy, RDT and uRDT, respectively. The agreement between qPCR and uRDT was almost perfect (Kappa = 0.82). For parasite density (qPCR) below 100 p/µL, the sensitivity of RDT was 62% (95% CI 47.1–75.3) compared to 68% (95% CI 53.3–80.4) for uRDT. Between 100 and 200 p/µL, the sensitivity of RDT was higher, but still lower compared to uRDT: 89.4% (95% CI 66.8–98.7) for RDT versus 100% (95% CI 82.3–100) for uRDT. In both cases, microscopy was lower, with 20% (95% CI 10–33.7) and 47.3% (95% CI 24.4–71.1) respectively. Conclusions: uRDT has the potential to improve malaria management in pregnant women as it has been found to be slightly more sensitive than RDT in the detection of malaria in pregnant women but the difference was not significant. Microscopy has a more limited value for the diagnosis of malaria during the pregnancy, because of its lower sensitivity. |
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