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1.
Ann Med Surg (Lond) ; 79: 104011, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35757307

ABSTRACT

Recently, the World Health Organization (WHO) approved RTS, S/AS01 (RTS, S) as the world's first malaria vaccine for partial malaria protection in young children at risk. While this immunization drive begins during the unprecedented pandemic of the SARS-CoV-2 Virus, the WHO has also approved 7 Vaccines in 2021 for the vaccination of children at risk. This article explores the quandary that would occur to the officials in charge of carrying out large vaccination campaigns against these two deadly infectious illnesses in several regions including the continent of Africa. The article also outlines the priorities for resolving this dilemma, offers evidence-based solutions, and provides a summary of recent significant events and their consequences. While providing the latest data, a discussion on the causation of the dilemma with clear recommendations for possible solutions has been explored as well.

2.
Malar J ; 21(1): 132, 2022 Apr 25.
Article in English | MEDLINE | ID: mdl-35468801

ABSTRACT

BACKGROUND: Following a 30-year development process, RTS,S/AS01E (GSK, Belgium) is the first malaria vaccine to reach Phase IV assessments. The World Health Organization-commissioned Malaria Vaccine Implementation Programme (MVIP) is coordinating the delivery of RTS,S/AS01E through routine national immunization programmes in areas of 3 countries in sub-Saharan Africa. The first doses were given in the participating MVIP areas in Malawi on 23 April, Ghana on 30 April, and Kenya on 13 September 2019. The countries participating in the MVIP have little or no baseline incidence data on rare diseases, some of which may be associated with immunization, a deficit that could compromise the interpretation of possible adverse events reported following the introduction of a new vaccine in the paediatric population. Further, effects of vaccination on malaria transmission, existing malaria control strategies, and possible vaccine-mediated selective pressure on Plasmodium falciparum variants, could also impact long-term malaria control. To address this data gap and as part of its post-approval commitments, GSK has developed a post-approval plan comprising of 4 complementary Phase IV studies that will evaluate safety, effectiveness and impact of RTS,S/AS01E through active participant follow-up in the context of its real-life implementation. METHODS: EPI-MAL-002 (NCT02374450) is a pre-implementation safety surveillance study that is establishing the background incidence rates of protocol-defined adverse events of special interest. EPI-MAL-003 (NCT03855995) is an identically designed post-implementation safety and vaccine impact study. EPI-MAL-005 (NCT02251704) is a cross-sectional pre- and post-implementation study to measure malaria transmission intensity and monitor the use of other malaria control interventions in the study areas, and EPI-MAL-010 (EUPAS42948) will evaluate the P. falciparum genetic diversity in the periods before and after vaccine implementation. CONCLUSION: GSK's post-approval plan has been designed to address important knowledge gaps in RTS,S/AS01E vaccine safety, effectiveness and impact. The studies are currently being conducted in the MVIP areas. Their implementation has provided opportunities and posed challenges linked to conducting large studies in regions where healthcare infrastructure is limited. The results from these studies will support ongoing evaluation of RTS,S/AS01E's benefit-risk and inform decision-making for its potential wider implementation across sub-Saharan Africa.


Subject(s)
Malaria Vaccines , Malaria, Falciparum , Malaria , Child , Cross-Sectional Studies , Humans , Infant , Kenya , Malaria/epidemiology , Malaria/prevention & control , Malaria, Falciparum/epidemiology , Malaria, Falciparum/prevention & control , Plasmodium falciparum
4.
Cell ; 185(5): 750-754, 2022 03 03.
Article in English | MEDLINE | ID: mdl-35245476

ABSTRACT

Malaria is estimated by the World Health Organization (WHO) to have killed 627,000 individuals worldwide in 2020, with nearly 80% of deaths in African children younger than five. The recent WHO approval of the RTS,S/AS01 vaccine, which targets Plasmodium falciparum pre-erythrocytic stages, provides hope that its use combined with other interventions can help reverse the current malaria resurgence.


Subject(s)
Malaria Vaccines , Malaria, Falciparum , Malaria , Child , Humans , Infant , Malaria/prevention & control , Malaria, Falciparum/prevention & control , Plasmodium falciparum
5.
Trends Parasitol ; 38(1): 9-10, 2022 01.
Article in English | MEDLINE | ID: mdl-34857495

ABSTRACT

Last month, the World Health Organization (WHO) recommended widespread use of RTS,S/AS01 vaccine to prevent malaria in young African children, noting its 30% reduction in deadly severe malaria. In a recent report, Das et al. describe antibody effector functions that may contribute to RTS,S efficacy and thereby guide vaccine improvements.


Subject(s)
Malaria Vaccines , Malaria, Falciparum , Malaria , Child , Humans , Infant , Malaria/prevention & control , Plasmodium falciparum
10.
Science ; 374(6565): 245-246, 2021 Oct 15.
Article in English | MEDLINE | ID: mdl-34648307
11.
BMJ ; 375: n2455, 2021 Oct 07.
Article in English | MEDLINE | ID: mdl-34620612
12.
N Engl J Med ; 385(11): 1005-1017, 2021 09 09.
Article in English | MEDLINE | ID: mdl-34432975

ABSTRACT

BACKGROUND: Malaria control remains a challenge in many parts of the Sahel and sub-Sahel regions of Africa. METHODS: We conducted an individually randomized, controlled trial to assess whether seasonal vaccination with RTS,S/AS01E was noninferior to chemoprevention in preventing uncomplicated malaria and whether the two interventions combined were superior to either one alone in preventing uncomplicated malaria and severe malaria-related outcomes. RESULTS: We randomly assigned 6861 children 5 to 17 months of age to receive sulfadoxine-pyrimethamine and amodiaquine (2287 children [chemoprevention-alone group]), RTS,S/AS01E (2288 children [vaccine-alone group]), or chemoprevention and RTS,S/AS01E (2286 children [combination group]). Of these, 1965, 1988, and 1967 children in the three groups, respectively, received the first dose of the assigned intervention and were followed for 3 years. Febrile seizure developed in 5 children the day after receipt of the vaccine, but the children recovered and had no sequelae. There were 305 events of uncomplicated clinical malaria per 1000 person-years at risk in the chemoprevention-alone group, 278 events per 1000 person-years in the vaccine-alone group, and 113 events per 1000 person-years in the combination group. The hazard ratio for the protective efficacy of RTS,S/AS01E as compared with chemoprevention was 0.92 (95% confidence interval [CI], 0.84 to 1.01), which excluded the prespecified noninferiority margin of 1.20. The protective efficacy of the combination as compared with chemoprevention alone was 62.8% (95% CI, 58.4 to 66.8) against clinical malaria, 70.5% (95% CI, 41.9 to 85.0) against hospital admission with severe malaria according to the World Health Organization definition, and 72.9% (95% CI, 2.9 to 92.4) against death from malaria. The protective efficacy of the combination as compared with the vaccine alone against these outcomes was 59.6% (95% CI, 54.7 to 64.0), 70.6% (95% CI, 42.3 to 85.0), and 75.3% (95% CI, 12.5 to 93.0), respectively. CONCLUSIONS: Administration of RTS,S/AS01E was noninferior to chemoprevention in preventing uncomplicated malaria. The combination of these interventions resulted in a substantially lower incidence of uncomplicated malaria, severe malaria, and death from malaria than either intervention alone. (Funded by the Joint Global Health Trials and PATH; ClinicalTrials.gov number, NCT03143218.).


Subject(s)
Amodiaquine/therapeutic use , Antimalarials/therapeutic use , Malaria Vaccines , Malaria, Falciparum/prevention & control , Pyrimethamine/therapeutic use , Sulfadoxine/therapeutic use , Antimalarials/adverse effects , Burkina Faso/epidemiology , Chemoprevention , Combined Modality Therapy , Double-Blind Method , Drug Combinations , Drug Therapy, Combination , Female , Hospitalization/statistics & numerical data , Humans , Infant , Malaria Vaccines/administration & dosage , Malaria Vaccines/adverse effects , Malaria, Falciparum/epidemiology , Malaria, Falciparum/mortality , Male , Mali/epidemiology , Seasons , Seizures, Febrile/etiology
13.
Malar J ; 20(1): 325, 2021 Jul 27.
Article in English | MEDLINE | ID: mdl-34315489

ABSTRACT

BACKGROUND: Malaria continues to be a major disease of public health concern affecting several million people worldwide. The World Health Organization (WHO) started a pilot study on a malaria vaccine (RTS,S) in Ghana and two other countries in 2019. This study aimed at assessing the factors associated with uptake of the vaccine in the Sunyani Municipality of Ghana. METHODS: The study was a cross-sectional study employing a quantitative approach. Stratified sampling technique was used to select respondents. A structured questionnaire was administered to parents/caregivers with children eligible to have taken the first three doses of the malaria vaccine by December 2019. The Child Welfare Clinic (CWC) cards of the eligible children were also inspected. Ordinal logistic regression analysis was done to determine the association between the independent variables and full vaccine uptake. RESULTS: Uptake of RTS,S 1 was 94.1%. However, this figure reduced to 90.6% for RTS,S 2, and 78.1% for RTS,S 3. Children with a parent who had been educated up to the tertiary level had 4.72 (AOR: 4.72, 95% CI 1.27-17.55) increased odds of full uptake as compared to those who completed secondary education. Parents whose children had experienced fever as an adverse reaction were more likely to send their children for the malaria vaccine as compared to those whose children had ever suffered abscess as an adverse reaction (AOR: 2.27, 95% CI 1.13-5.10). Children with parents who thought vaccines were becoming too many for children had 71% (AOR: 0.29, 95% CI 0.14-0.61) reduced odds of full uptake as compared to those who thought otherwise. CONCLUSION: Uptake of RTS,S 1 and RTS,S 2 in Sunyani Municipality meets the WHO's target coverage for vaccines, however, RTS,S 3 uptake does not. Furthermore, there is a growing perception amongst parents/caregivers that vaccines are becoming too many for children which negatively affects uptake.


Subject(s)
Health Knowledge, Attitudes, Practice , Malaria Vaccines/therapeutic use , Vaccination Coverage/statistics & numerical data , Adolescent , Adult , Female , Ghana , Humans , Infant , Male , Middle Aged , Young Adult
14.
Vaccine ; 39(22): 2907-2916, 2021 05 21.
Article in English | MEDLINE | ID: mdl-33931251

ABSTRACT

Considerable progress has been made in malaria control in the last two decades, but progress has stalled in the last few years. New tools are needed to achieve public health goals in malaria control and elimination. A first generation vaccine, RTS,S/AS01, is currently being evaluated as it undergoes pilot implementation through routine health systems in parts of three African countries. The development of this vaccine took over 30 years and has been full of uncertainties. Even now, important unknowns remain as to its future role in public health. Lessons need to be learnt for second generation and future vaccines, including how to facilitate early planning of investments, streamlining of development, regulatory and policy pathways. A number of candidate vaccines populate the current development pipeline, some of which have the potential to contribute to burden reduction if efficacy is confirmed in conditions of natural exposure, and if they are amenable to affordable supply and programmatic implementation. New, innovative technologies will be needed if future malaria vaccines are to overcome important scientific hurdles and induce durable, high level protection. WHO convened a stakeholder consultation on the status of malaria vaccine research and development to inform the recently reconstituted Malaria Vaccine Advisory Committee (MALVAC) which will assist WHO in updating its current guidance and recommendations about priorities and product preferences for malaria vaccines.


Subject(s)
Malaria Vaccines , Malaria, Falciparum , Malaria , Africa , Humans , Malaria/prevention & control , Referral and Consultation , World Health Organization
16.
Risk Manag Healthc Policy ; 14: 1033-1039, 2021.
Article in English | MEDLINE | ID: mdl-33737844

ABSTRACT

BACKGROUND: Recent advances in mosquito eradication and antimalarial treatments have reduced the malaria burden only modestly. An effective malaria vaccine remains a high priority, but its development has several challenges. Among many potential candidates, the RTS,S/AS01 vaccine (MosquirixTM) remains the leading candidate. OBJECTIVE AND METHOD: This review aims to understand the advances in the RTS,S/AS01 vaccine, and future comments regarding the vaccine's effectiveness in malaria eradication. Literature review for the past five decades was performed searching PubMed, EMBASE Ovid, and Cochrane Library, with using the following search items: ("malaria" OR "WHO's malaria" OR "Plasmodium falciparum" OR "RTS,S" OR "RTS,S/AS01" OR "RTS,S/AS02" OR "pre-erythrocytic malaria" OR "circumsporozoite" OR "Mosquirix") AND ("vaccine" OR "vaccination"). RESULTS: RTS,S/AS01, a recombinant pre-erythrocytic vaccine containing Plasmodium falciparum surface-protein (circumsporozoite) antigen, is safe, well-tolerated, and immunogenic in children. Three doses, along with a booster, have a modest efficacy of about 36% in children (age 5-17 months) and about 26% in infants (age 6-12 weeks) against clinical malaria during a 48-month follow-up. However, the efficacy varies among population subgroups and with the parasite strain, it reduces without a booster and offers protection for a limited duration. Because of its potential cost-effectiveness and positive public health effect, the vaccine is being investigated in a pilot program for mortality benefits and broader deployment. CONCLUSION: The RTS,S/AS01 vaccine prevents malaria; however, it should be considered another addition to the malaria-control program and not as an eradication tool because of its relatively low to modest efficacy.

17.
Article in English | MEDLINE | ID: mdl-33533814

ABSTRACT

Malaria represents a serious public health problem, presenting with high rates of incidence, morbidity and mortality in tropical and subtropical regions of the world. According to the World Health Organization, in 2018 there were 228 million cases and 405 thousand deaths caused by this disease in the world, affecting mainly children and pregnant women in Africa. Despite the programs carried out to control this disease, drug resistance and invertebrate vector resistance to insecticides have generated difficulties. An efficient vaccine against malaria would be a strategy with a high impact on the eradication and control of this disease. Researches aimed at developing vaccines have focused on antigens of high importance for the survival of the parasite such as the Circumsporozoite Surface Protein, involved in the pre-erythrocytic cycle during parasites invasion in hepatocytes. Currently, RTS'S is the most promising vaccine for malaria and was constructed using CSP; its performance was evaluated using two types of adjuvants: AS01 and AS02. The purpose of this review was to provide a bibliographic survey of historical researches that led to the development of RTS'S and its performance analysis over the decade. The search for new adjuvants to be associated with this antigen seems to be a way to obtain higher percentages of protection for a future malaria vaccine.


Subject(s)
Malaria Vaccines/therapeutic use , Malaria/prevention & control , Plasmodium falciparum/genetics , Plasmodium falciparum/metabolism , Protozoan Proteins , Humans , Malaria/parasitology , Malaria Vaccines/administration & dosage , Membrane Proteins
18.
PLoS One ; 16(1): e0244995, 2021.
Article in English | MEDLINE | ID: mdl-33428635

ABSTRACT

BACKGROUND: The RTS,S/ASO1E malaria vaccine is being piloted in three countries-Ghana, Kenya, and Malawi-as part of a coordinated evaluation led by the World Health Organization, with support from global partners. This study estimates the costs of continuing malaria vaccination upon completion of the pilot evaluation to inform decision-making and planning around potential further use of the vaccine in pilot areas. METHODS: We used an activity-based costing approach to estimate the incremental costs of continuing to deliver four doses of RTS,S/ASO1E through the existing Expanded Program on Immunization platform, from each government's perspective. The RTS,S/ASO1E pilot introduction plans were reviewed and adapted to identify activities for costing. Key informant interviews with representatives from Ministries of Health (MOH) were conducted to inform the activities, resource requirements, and assumptions that, in turn, inform the analysis. Both financial and economic costs per dose, cost of delivery per dose, and cost per fully vaccinated child (FVC) are estimated and reported in 2017 USD units. RESULTS: At a vaccine price of $5 per dose and assuming the vaccine is donor-funded, our estimated incremental financial costs range from $1.70 (Kenya) to $2.44 (Malawi) per dose, $0.23 (Malawi) to $0.71 (Kenya) per dose delivered (excluding procurement add-on costs), and $11.50 (Ghana) to $13.69 (Malawi) per FVC. Estimates of economic costs per dose are between three and five times higher than financial costs. Variations in activities used for costing, procurement add-on costs, unit costs of per diems, and allowances contributed to differences in cost estimates across countries. CONCLUSION: Cost estimates in this analysis are meant to inform country decision-makers as they face the question of whether to continue malaria vaccination, should the intervention receive a positive recommendation for broader use. Additionally, important cost drivers for vaccine delivery are highlighted, some of which might be influenced by global and country-specific financing and existing procurement mechanisms. This analysis also adds to the evidence available on vaccine delivery costs for products delivered outside the standard immunization schedule.


Subject(s)
Health Care Costs , Immunization Programs/economics , Malaria Vaccines/economics , Malaria/prevention & control , Vaccination/economics , Cost-Benefit Analysis , Ghana , Humans , Kenya , Malawi , World Health Organization
19.
Explor Res Clin Soc Pharm ; 3: 100063, 2021 Sep.
Article in English | MEDLINE | ID: mdl-35480603

ABSTRACT

Background: In Rwanda, malaria affects one in six children under five years old. Despite being preventable and treatable, malaria causes substantial morbidity, mortality, and economic burden on the Rwandan government and healthcare donors. Recently, the World Health Organization (WHO) agreed to consider the new malaria vaccine (RTS, S) as an additional prevention strategy. The Global Fund, a healthcare donor, is committed to donating more than fifty million US dollars over four years (2018-2021) to fight malaria in Rwanda. We estimated the potential budget impact of the adoption of RTS, S, into the Global Fund budget (as a case study) for malaria prevention in Rwanda. Methods: We developed a static budget impact model based on clinical, epidemiological, and cost (in US dollars) data from the literature, to assess the financial consequences of adding RTS, S to existing prevention strategies. Cost of treatment and prevention for the first year (without vaccine) was estimated and compared to the total cost after the fifth year (with vaccine). A one-way sensitivity analysis evaluated the robustness of the model. Results: For the 283,931children under 5 years at risk of malaria in Rwanda every year, the expected budget for first year (without vaccine) was $1,328,377.71 and for the fifth year (with vaccine) was $3,837,804, yielding a potential budget impact of $2,509,427. The cost of treating un-prevented malaria for the first year was $736,959 and for the fifth year was $61,413. The annual number of malaria treatments avoided increased from 10,095 children in the first year after introduction of vaccine to 36,701 children at the fifth year. Conclusion: With a potential budget impact of $2,509,427, the introduction of malaria vaccine for children under 5 years by Global Fund in Rwanda may be affordable when compared to the amount spent on treating children with malaria. Given that Malaria causes more harm than most parasitic diseases and disproportionally affects low-income populations, it is ethical to deploy all measures to control or eliminate Malaria, including vaccination.

20.
PLoS Med ; 17(11): e1003377, 2020 11.
Article in English | MEDLINE | ID: mdl-33253211

ABSTRACT

BACKGROUND: The RTS,S/AS01 vaccine against Plasmodium falciparum malaria infection completed phase III trials in 2014 and demonstrated efficacy against clinical malaria of approximately 36% over 4 years for a 4-dose schedule in children aged 5-17 months. Pilot vaccine implementation has recently begun in 3 African countries. If the pilots demonstrate both a positive health impact and resolve remaining safety concerns, wider roll-out could be recommended from 2021 onwards. Vaccine demand may, however, outstrip initial supply. We sought to identify where vaccine introduction should be prioritised to maximise public health impact under a range of supply constraints using mathematical modelling. METHODS AND FINDINGS: Using a mathematical model of P. falciparum malaria transmission and RTS,S vaccine impact, we estimated the clinical cases and deaths averted in children aged 0-5 years in sub-Saharan Africa under 2 scenarios for vaccine coverage (100% and realistic) and 2 scenarios for other interventions (current coverage and World Health Organization [WHO] Global Technical Strategy targets). We used a prioritisation algorithm to identify potential allocative efficiency gains from prioritising vaccine allocation among countries or administrative units to maximise cases or deaths averted. If malaria burden at introduction is similar to current levels-assuming realistic vaccine coverage and country-level prioritisation in areas with parasite prevalence >10%-we estimate that 4.3 million malaria cases (95% credible interval [CrI] 2.8-6.8 million) and 22,000 deaths (95% CrI 11,000-35,000) in children younger than 5 years could be averted annually at a dose constraint of 30 million. This decreases to 3.0 million cases (95% CrI 2.0-4.7 million) and 14,000 deaths (95% CrI 7,000-23,000) at a dose constraint of 20 million, and increases to 6.6 million cases (95% CrI 4.2-10.8 million) and 38,000 deaths (95% CrI 18,000-61,000) at a dose constraint of 60 million. At 100% vaccine coverage, these impact estimates increase to 5.2 million cases (95% CrI 3.5-8.2 million) and 27,000 deaths (95% CrI 14,000-43,000), 3.9 million cases (95% CrI 2.7-6.0 million) and 19,000 deaths (95% CrI 10,000-30,000), and 10.0 million cases (95% CrI 6.7-15.7 million) and 51,000 deaths (95% CrI 25,000-82,000), respectively. Under realistic vaccine coverage, if the vaccine is prioritised sub-nationally, 5.3 million cases (95% CrI 3.5-8.2 million) and 24,000 deaths (95% CrI 12,000-38,000) could be averted at a dose constraint of 30 million. Furthermore, sub-national prioritisation would allow introduction in almost double the number of countries compared to national prioritisation (21 versus 11). If vaccine introduction is prioritised in the 3 pilot countries (Ghana, Kenya, and Malawi), health impact would be reduced, but this effect becomes less substantial (change of <5%) if 50 million or more doses are available. We did not account for within-country variation in vaccine coverage, and the optimisation was based on a single outcome measure, therefore this study should be used to understand overall trends rather than guide country-specific allocation. CONCLUSIONS: These results suggest that the impact of constraints in vaccine supply on the public health impact of the RTS,S malaria vaccine could be reduced by introducing the vaccine at the sub-national level and prioritising countries with the highest malaria incidence.


Subject(s)
Malaria Vaccines , Malaria, Falciparum/prevention & control , Malaria/prevention & control , Models, Theoretical , Child , Child, Preschool , Female , Ghana , Humans , Incidence , Infant , Infant, Newborn , Kenya , Malaria/epidemiology , Malaria Vaccines/administration & dosage , Malaria Vaccines/pharmacology , Malaria, Falciparum/epidemiology , Malawi , Male , Public Health/statistics & numerical data
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