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Schmit N, Topazian HM, Natama HM, Bellamy D, Traoré O, Somé MA, Rouamba T, Tahita MC, Bonko MDA, Sourabié A, Sorgho H, Stockdale L, Provstgaard-Morys S, Aboagye J, Woods D, Rapi K, Datoo MS, Lopez FR, Charles GD, McCain K, Ouedraogo JB, Hamaluba M, Olotu A, Dicko A, Tinto H, Hill AVS, Ewer KJ, Ghani AC, Winskill P. The public health impact and cost-effectiveness of the R21/Matrix-M malaria vaccine: a mathematical modelling study. THE LANCET. INFECTIOUS DISEASES 2024; 24:465-475. [PMID: 38342107 DOI: 10.1016/s1473-3099(23)00816-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 02/13/2024]
Abstract
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.
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Affiliation(s)
- Nora Schmit
- UK Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK.
| | - Hillary M Topazian
- UK Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
| | - H Magloire Natama
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Duncan Bellamy
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Ousmane Traoré
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - M Athanase Somé
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Toussaint Rouamba
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Marc Christian Tahita
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Massa Dit Achille Bonko
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Aboubakary Sourabié
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Hermann Sorgho
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Lisa Stockdale
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | | | - Jeremy Aboagye
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Danielle Woods
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Katerina Rapi
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Mehreen S Datoo
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | | | - Giovanni D Charles
- UK Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
| | - Kelly McCain
- UK Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
| | - Jean-Bosco Ouedraogo
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso; Institut des Sciences et Techniques-Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Mainga Hamaluba
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Ally Olotu
- Clinical Trials and Interventions Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Alassane Dicko
- The Malaria Research and Training Centre, University of Science, Technology, and Techniques of Bamako, Bamako, Mali
| | - Halidou Tinto
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso; Institut des Sciences et Techniques-Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Adrian V S Hill
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Katie J Ewer
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK; GSK Vaccines Institute for Global Health (Global Health Vaccines R&D), GSK, Siena, Italy
| | - Azra C Ghani
- UK Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
| | - Peter Winskill
- UK Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
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Abstract
RTS,S/AS01 (Mosquirix®) is a vaccine against malaria caused by Plasmodium falciparum. In a phase 3 trial, RTS,S/AS01 showed vaccine efficacy against clinical malaria, severe malaria and malaria hospitalization, with an acceptable safety and tolerability profile, in children aged 6 weeks to 17 months; the vaccine efficacy was greater in children than in infants and waned over time. In another phase 3 trial, RTS,S/AS01 was noninferior to seasonal malaria chemoprevention in children. WHO recommends a 4-dose schedule of RTS,S/AS01 for the prevention of P. falciparum malaria in children from 5 months of age living in regions with moderate to high malaria transmission, with an optional 5-dose schedule for areas with highly seasonal malaria transmission. First results from large pilot implementation in Africa show that RTS,S/AS01 has a favourable safety profile, increases equity in access to malaria prevention, is highly cost effective, can be delivered through routine national immunization programmes and substantially reduces severe malaria burden. Malaria is a life-threatening disease caused by Plasmodium parasites, which are spread to humans through bites of infected mosquitoes. RTS,S/AS01 (Mosquirix®) is a vaccine against malaria caused by P. falciparum. In phase 3 trials, RTS,S/AS01 showed vaccine efficacy against P. falciparum malaria and was at least as effective as seasonal malaria chemoprevention in children, with an acceptable safety and tolerability profile. Results of the first 2 years of a large scale pilot implementation of RTS,S/AS01 in Africa allowed WHO to recommend the vaccine for the prevention of P. falciparum malaria in children from 5 months of age living in regions with moderate to high malaria transmission, with an optional use for seasonal malaria.
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