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Hamilton A, Haghpanah F, Hasso-Agopsowicz M, Frost I, Lin G, Schueller E, Klein E, Laxminarayan R. Modeling of malaria vaccine effectiveness on disease burden and drug resistance in 42 African countries. COMMUNICATIONS MEDICINE 2023; 3:144. [PMID: 37833540 PMCID: PMC10576074 DOI: 10.1038/s43856-023-00373-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND The emergence of antimalarial drug resistance poses a major threat to effective malaria treatment and control. This study aims to inform policymakers and vaccine developers on the potential of an effective malaria vaccine in reducing drug-resistant infections. METHODS A compartmental model estimating cases, drug-resistant cases, and deaths averted from 2021 to 2030 with a vaccine against Plasmodium falciparum infection administered yearly to 1-year-olds in 42 African countries. Three vaccine efficacy (VE) scenarios and one scenario of rapidly increasing drug resistance are modeled. RESULTS When VE is constant at 40% for 4 years and then drops to 0%, 235.7 (Uncertainty Interval [UI] 187.8-305.9) cases per 1000 children, 0.6 (UI 0.4-1.0) resistant cases per 1000, and 0.6 (UI 0.5-0.9) deaths per 1000 are averted. When VE begins at 80% and drops 20 percentage points each year, 313.9 (UI 249.8-406.6) cases per 1000, 0.9 (UI 0.6-1.3) resistant cases per 1000, and 0.9 (UI 0.6-1.2) deaths per 1000 are averted. When VE remains 40% for 10 years, 384.7 (UI 311.7-496.5) cases per 1000, 1.0 (0.7-1.6) resistant cases per 1000, and 1.1 (UI 0.8-1.5) deaths per 1000 are averted. Assuming an effective vaccine and an increase in current levels of drug resistance to 80% by 2030, 10.4 (UI 7.3-15.8) resistant cases per 1000 children are averted. CONCLUSIONS Widespread deployment of a malaria vaccine could substantially reduce health burden in Africa. Maintaining VE longer may be more impactful than a higher initial VE that falls rapidly.
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Affiliation(s)
| | | | | | - Isabel Frost
- World Health Organization, Geneva, Switzerland
- Imperial College London, London, UK
| | - Gary Lin
- One Health Trust, Washington, D.C., USA
| | | | - Eili Klein
- One Health Trust, Washington, D.C., USA
- Johns Hopkins University, Department of Emergency Medicine, Baltimore, MD, USA
| | - Ramanan Laxminarayan
- One Health Trust, Washington, D.C., USA.
- One Health Trust, New Delhi, India.
- Princeton University, Princeton, NJ, USA.
- University of Washington, Seattle, WA, USA.
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2
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Mak J, Sriudomporn S, Moss WJ, Patenaude BN. An Estimate Of The Return On Investment Of A Malaria Vaccine In 20 Sub-Saharan African Countries, 2021-30. Health Aff (Millwood) 2023; 42:1091-1099. [PMID: 37549331 DOI: 10.1377/hlthaff.2022.01328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Malaria is a leading global health problem that was responsible for an estimated 619,000 deaths worldwide in 2021. We modeled the return on investment (ROI) for the introduction and continuation of a four-dose malaria vaccine, RTS,S/AS01, from 2021 to 2030 in twenty sub-Saharan African countries supported by Gavi, the Vaccine Alliance. We used the Decade of Vaccine Economics benefits and costing outputs to calculate an ROI using health impact data modeled by the Swiss Tropical and Public Health Institute (hereafter "Swiss") and Imperial College London (hereafter "Imperial"). The Swiss estimates with a base vaccine price of US$7.00 resulted in an ROI of 0.42, and the Imperial impact estimates with the same base vaccine price resulted in an ROI of 2.30. Inclusion of the fifth seasonal dose for ten countries exhibiting high seasonal disease burden increased the Swiss ROI by 143 percent, to 1.02, and the Imperial ROI by 23.5 percent, to 2.84. To improve ROI, decision makers should continue to improve delivery platforms, decrease vaccine delivery costs, deliver the malaria vaccine in fewer doses, and provide access to vaccine resources.
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Affiliation(s)
- Joshua Mak
- Joshua Mak , Johns Hopkins University, Baltimore, Maryland
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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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Hutter JN, Robben PM, Lee C, Hamer M, Moon JE, Merino K, Zhu L, Galli H, Quinn X, Brown DR, Duncan E, Bolton J, Zou X, Angov E, Lanar DE, Rao M, Matyas GR, Beck Z, Bergmann-Leitner E, Soisson LA, Waters NC, Ngauy V, Regules J, Dutta S. First-in-human assessment of safety and immunogenicity of low and high doses of Plasmodium falciparum malaria protein 013 (FMP013) administered intramuscularly with ALFQ adjuvant in healthy malaria-naïve adults. Vaccine 2022; 40:5781-5790. [PMID: 36055874 DOI: 10.1016/j.vaccine.2022.08.048] [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: 04/17/2022] [Revised: 07/19/2022] [Accepted: 08/20/2022] [Indexed: 11/30/2022]
Abstract
The global burden of malaria remains substantial. Circumsporozoite protein (CSP) has been demonstrated to be an effective target antigen, however, improvements that offer more efficacious and more durable protection are still needed. In support of research and development of next-generation malaria vaccines, Walter Reed Army Institute of Research (WRAIR) has developed a CSP-based antigen (FMP013) and a novel adjuvant ALFQ (Army Liposome Formulation containing QS-21). We present a single center, open-label, dose-escalation Phase 1 clinical trial to evaluate the safety and immunogenicity of the FMP013/ALFQ malaria vaccine candidate. In this first-in-human evaluation of both the antigen and adjuvant, we enrolled ten subjects; five received 20 μg FMP013 / 0.5 mL ALFQ (Low dose group), and five received 40 μg FMP013 / 1.0 mL ALFQ (High dose group) on study days 1, 29, and 57. Adverse events and immune responses were assessed during the study period. The clinical safety profile was acceptable and there were no serious adverse events. Both groups exhibited robust humoral and cellular immunological responses, and compared favorably with historical responses reported for RTS,S/AS01. Based on a lower reactogenicity profile, the 20 μg FMP013 / 0.5 mL ALFQ (Low dose) was selected for follow-on efficacy testing by controlled human malaria infection (CHMI) with a separate cohort. Trial Registration:Clinicaltrials.gov Identifier NCT04268420 (Registered February 13, 2020).
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Affiliation(s)
- Jack N Hutter
- Walter Reed Army Institute of Research, Silver Spring, MD, United States.
| | - Paul M Robben
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Christine Lee
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Melinda Hamer
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - James E Moon
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Kristen Merino
- Walter Reed Army Institute of Research, Silver Spring, MD, United States; Current Affiliation: Division of Immunology, Tulane National Primate Research Center Covington, LA, United States
| | - Lei Zhu
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Heather Galli
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Xiaofei Quinn
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Dallas R Brown
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Elizabeth Duncan
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Jessica Bolton
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Xiaoyan Zou
- Navy Medical Research Center, Silver Spring, United States
| | - Evelina Angov
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - David E Lanar
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Mangala Rao
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Gary R Matyas
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Zoltan Beck
- Walter Reed Army Institute of Research, Silver Spring, MD, United States; Henry Jackson Foundation for Advancement of Military Medicine, Bethesda, MD. Present Address: Pfizer, Inc., 401 N Middletown Rd, Pearl River, New York 10965, United States
| | | | - Lorraine A Soisson
- United States Agency for International Development Malaria Vaccine Development Program, Washington DC, United States
| | - Norman C Waters
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Viseth Ngauy
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Jason Regules
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Sheetij Dutta
- Walter Reed Army Institute of Research, Silver Spring, MD, United States.
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Nguyen TT, Gryseels C, Tran DT, Smekens T, Gerrets R, Nguyen XX, Peeters Grietens K. Understanding Malaria Persistence: A Mixed-Methods Study on the Effectiveness of Malaria Elimination Strategies in South-Central Vietnam. Front Public Health 2021; 9:742378. [PMID: 34950624 PMCID: PMC8688690 DOI: 10.3389/fpubh.2021.742378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/02/2021] [Indexed: 11/17/2022] Open
Abstract
Despite the scale-up of vector control, diagnosis and treatment, and health information campaigns, malaria persists in the forested areas of South-Central Vietnam, home to ethnic minority populations. A mixed-methods study using an exploratory sequential design was conducted in 10 Ra-glai villages in Bac Ai district of Ninh Thuan province to examine which social factors limited the effectiveness of the national malaria elimination strategy in the local setting. Territorial arrangements and mobility were found to directly limit the effectiveness of indoor residual spraying and long-lasting insectidical treated nets (LLINs). Households (n=410) were resettled in the “new villages” by the government, where they received brick houses (87.1%) and sufficient LLINs (97.3%). However, 97.6% of households went back to their “old villages” to continue slash-and-burn agriculture. In the old village, 48.5% of households lived in open-structured plot huts and only 5.7% of them had sufficient LLIN coverage. Household representatives believed malaria could be cured with antimalarials (57.8%), but also perceived non-malarial medicines, rituals, and vitamin supplements to be effective against malaria. Household members (n = 1,957) used public health services for their most recent illness (62.9%), but also reported to buy low-cost medicines from the private sector to treat fevers and discomfort as these were perceived to be the most cost-effective treatment option for slash-and-burn farmers. The study shows the relevance of understanding social factors to improve the uptake of public health interventions and calls for contextually adapted strategies for malaria elimination in ethnic minority populations in Vietnam and similar settings.
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Affiliation(s)
- Thuan Thi Nguyen
- Department of Malaria Epidemiology, National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.,Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium.,Faculty of Social and Behavioural Sciences, Amsterdam Institute for Social Science Research (AISSR), University of Amsterdam, Amsterdam, Netherlands
| | - Charlotte Gryseels
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Duong Thanh Tran
- Department of Malaria Epidemiology, National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Tom Smekens
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - René Gerrets
- Faculty of Social and Behavioural Sciences, Amsterdam Institute for Social Science Research (AISSR), University of Amsterdam, Amsterdam, Netherlands.,Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, Netherlands
| | - Xa Xuan Nguyen
- Department of Malaria Epidemiology, National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam
| | - Koen Peeters Grietens
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium.,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
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Galactionova K, Smith TA, Penny MA. Insights from modelling malaria vaccines for policy decisions: the focus on RTS,S. Malar J 2021; 20:439. [PMID: 34794430 PMCID: PMC8600337 DOI: 10.1186/s12936-021-03973-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 11/04/2021] [Indexed: 11/17/2022] Open
Abstract
Mathematical models are increasingly used to inform decisions throughout product development pathways from pre-clinical studies to country implementation of novel health interventions. This review illustrates the utility of simulation approaches by reviewing the literature on malaria vaccine modelling, with a focus on its link to the development of policy guidance for the first licensed product, RTS,S/AS01. The main contributions of modelling studies have been in inferring the mechanism of action and efficacy profile of RTS,S; to predicting the public health impact; and economic modelling mainly comprising cost-effectiveness analysis. The value of both product-specific and generic modelling of vaccines is highlighted.
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Affiliation(s)
- Katya Galactionova
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland.,University of Basel, 4001, Basel, Switzerland.,European Center of Pharmaceutical Medicine, Brombacherstrasse 5, 4057, Basel, Switzerland
| | - Thomas A Smith
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland. .,University of Basel, 4001, Basel, Switzerland.
| | - Melissa A Penny
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland.,University of Basel, 4001, Basel, Switzerland
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Yerushalmi E, Hunt P, Hoorens S, Sauboin C, Smith R. Exploring the Use of a General Equilibrium Method to Assess the Value of a Malaria Vaccine: An Application to Ghana. MDM Policy Pract 2019; 4:2381468319894345. [PMID: 31903422 PMCID: PMC6923699 DOI: 10.1177/2381468319894345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 11/05/2019] [Indexed: 01/16/2023] Open
Abstract
Background. Malaria is an important health and economic burden in
sub-Saharan Africa. Conventional economic evaluations typically consider only
direct costs to the health care system and government budgets. This paper
quantifies the potential impact of malaria vaccination on the wider economy,
using Ghana as an example. Methods. We used a computable general
equilibrium model of the Ghanaian economy to estimate the macroeconomic impact
of malaria vaccination in children under the age of 5, with a vaccine efficacy
of 50% against clinical malaria and 20% against malaria mortality. The model
considered changes in demography and labor productivity, and projected gross
domestic product (GDP) over a time frame of 30 years. Vaccine coverage ranging
from 20% to 100% was compared with a baseline with no vaccination.
Results. Malaria vaccination with 100% coverage was projected
to increase the GDP of Ghana over 30 years by US$6.93 billion (in 2015 prices)
above the baseline without vaccination, equivalent to an increase in annual GDP
growth of 0.5%. Projected GDP per capita would increase in the first year due to
immediate reductions in time lost from work by adults caring for children with
malaria, then decrease for several years as reductions in child mortality
increase the number of dependent children, then show a sustained increase after
Year 11 due to long-term productivity improvements in adults resulting from
fewer malaria episodes in childhood. Conclusion. Investing in
improving childhood health by vaccinating against malaria could result in
substantial long-term macroeconomic benefits when these children enter the
workforce as adults. These macroeconomic benefits are not captured by
conventional economic evaluations and constitute an important potential benefit
of vaccination.
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Affiliation(s)
- Erez Yerushalmi
- Birmingham City Business School, Birmingham City University, Birmingham, UK
| | | | | | | | - Richard Smith
- College of Medicine and Health, University of Exeter, Exeter, UK
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