New interventions are needed to reduce morbidity and mortality associated with malaria, as well as to accelerate elimination and eventual eradication. Interventions that can break the cycle of parasite transmission, and prevent its reintroduction, will be of particular importance in achieving the eradication goal. In this regard, vaccines that interrupt malaria transmission (VIMT) have been highlighted as an important intervention, including transmission-blocking vaccines that prevent human-to-mosquito transmission by targeting the sexual, sporogonic, or mosquito stages of the parasite (SSM-VIMT).
View Article and Find Full Text PDFBackground: Efforts to develop malaria vaccines show promise. Mathematical model-based estimates of the potential demand, public health impact, and cost and financing requirements can be used to inform investment and adoption decisions by vaccine developers and policymakers on the use of malaria vaccines as complements to existing interventions. However, the complexity of such models may make their outputs inaccessible to non-modeling specialists.
View Article and Find Full Text PDFWith the advent of new vaccines targeted to highly endemic diseases in low- and middle-income countries (LMIC) and with the expansion of vaccine manufacturing globally, there is an urgent need to establish an infrastructure to evaluate the benefit-risk profiles of vaccines in LMIC. Fortunately the usual decade(s)-long time gap between introduction of new vaccines in high and low income countries is being significantly reduced or eliminated due to initiatives such as the Global Alliance for Vaccines and Immunizations (GAVI) and the Decade of Vaccines for the implementation of the Global Vaccine Action Plan. While hoping for more rapid disease control, this time shift may potentially add risk, unless appropriate capacity for reliable and timely evaluation of vaccine benefit-risk profiles in some LMIC's are developed with external assistance from regional or global level.
View Article and Find Full Text PDFWhile recent progress has been made in reducing malaria mortality with other interventions, vaccines are still urgently needed to further reduce the incidence of clinical disease, including during pregnancy, and to provide "herd protection" by blocking parasite transmission. The most clinically advanced candidate, RTS,S, is presently undergoing Phase 3 evaluation in young African children across 13 clinical sites in eight African countries. In the 12-month period following vaccination, RTS,S conferred approximately 50% protection from clinical Plasmodium falciparum disease in children aged 5-17 months, and approximately 30% protection in children aged 6-12 weeks when administered in conjunction with Expanded Program for Immunization (EPI) vaccines.
View Article and Find Full Text PDFVaccines are considered as one of the major contributions of the 20th century and one of the most cost effective public health interventions. The International Vaccine Institute has as a mission to discover, develop and deliver new and improved vaccines against infectious diseases that affects developing nations. If Louis Pasteur is known across the globe, vaccinologists like Maurice Hilleman, Jonas Salk and Charles Mérieux are known among experts only despite their contribution to global health.
View Article and Find Full Text PDFBackground: The candidate malaria vaccine RTS,S/AS01 reduced episodes of both clinical and severe malaria in children 5 to 17 months of age by approximately 50% in an ongoing phase 3 trial. We studied infants 6 to 12 weeks of age recruited for the same trial.
Methods: We administered RTS,S/AS01 or a comparator vaccine to 6537 infants who were 6 to 12 weeks of age at the time of the first vaccination in conjunction with Expanded Program on Immunization (EPI) vaccines in a three-dose monthly schedule.
Many new interventions are being created to address health problems of the developing world. However, many developing countries have fragile health systems and find it difficult to accommodate change. Consequently, it is essential that new interventions are well aligned with health systems and their users.
View Article and Find Full Text PDFN Engl J Med
November 2011
Background: An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries.
Methods: From March 2009 through January 2011, we enrolled 15,460 children in two age categories--6 to 12 weeks of age and 5 to 17 months of age--for vaccination with either RTS,S/AS01 or a non-malaria comparator vaccine. The primary end point of the analysis was vaccine efficacy against clinical malaria during the 12 months after vaccination in the first 6000 children 5 to 17 months of age at enrollment who received all three doses of vaccine according to protocol.
Background: GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative are working in partnership to develop a malaria vaccine to protect infants and children living in malaria endemic regions of sub-Saharan Africa, which can be delivered through the Expanded Programme on Immunization. The RTS,S/AS candidate vaccine has been evaluated in multiple phase I/II studies and shown to have a favourable safety profile and to be well-tolerated in both adults and children. This paper details the design of the phase III multicentre efficacy trial of the RTS,S/AS01 malaria vaccine candidate, which is pivotal for licensure and policy decision-making.
View Article and Find Full Text PDFHealth Aff (Millwood)
June 2011
With approximately 225 million new cases and 800,000 deaths annually, malaria exacts a tremendous toll--mostly on African children under the age of five. Late-stage trials of an advanced malaria vaccine candidate--which, if approved, would become the world's first malaria vaccine--are under way, and it may be ready for use by 2015. This article recounts the pivotal roles in that achievement played by collaborations of nonprofit organizations, pharmaceutical companies, private and public donors, and countries whose citizens would benefit most directly from a vaccine.
View Article and Find Full Text PDFPrevious studies with the malaria vaccine RTS,S/AS02(A) in young children in a malaria endemic area of Mozambique have shown it to have a promising safety profile and to reduce the risk of Plasmodium falciparum infection and disease. In this study, we assessed the antibody responses to the P. falciparum and hepatitis B components of the RTS,S/AS02(A) vaccine over a 45 months surveillance period in a large phase IIb trial which included 2022 children aged 1-4 years at recruitment.
View Article and Find Full Text PDFBackground: The RTS,S/AS02(D) vaccine has been shown to have a promising safety profile, to be immunogenic and to confer protection against malaria in children and infants.
Methods And Findings: We did a randomized, controlled, phase I/IIb trial of RTS,S/AS02(D) given at 10, 14 and 18 weeks of age staggered with routine immunization vaccines in 214 Mozambican infants. The study was double-blind until the young child completed 6 months of follow-up over which period vaccine efficacy against new Plasmodium falciparum infections was estimated at 65.
Background: The pre-erythrocytic malaria vaccine RTS,S/AS02A has shown to confer protection against clinical malaria for at least 21 months in a trial in Mozambican children. Efficacy varied between different endpoints, such as parasitaemia or clinical malaria; however the underlying mechanisms that determine efficacy and its duration remain unknown. We performed a new, exploratory analysis to explore differences in the duration of protection among participants to better understand the protection afforded by RTS,S.
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