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1.
Vaccine ; 32(43): 5531-9, 2014 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-25077422

RESUMO

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). While the significant potential of this vaccine approach has been appreciated for decades, the development and licensure pathways for vaccines that target transmission and the incidence of infection, as opposed to prevention of clinical malaria disease, remain ill-defined. This article describes the progress made in critical areas since 2010, highlights key challenges that remain, and outlines important next steps to maximize the potential for SSM-VIMTs to contribute to the broader malaria elimination and eradication objectives.


Assuntos
Pesquisa Biomédica/tendências , Vacinas Antimaláricas , Malária/prevenção & controle , Animais , Culicidae/parasitologia , Humanos , Insetos Vetores/parasitologia , Malária/transmissão
2.
BMC Infect Dis ; 13: 295, 2013 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-23815273

RESUMO

BACKGROUND: 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. This paper describes a Malaria Vaccine Model (MVM) developed to address the specific needs of developers and policymakers, who need to access sophisticated modeling results and to test various scenarios in a user-friendly interface. The model's functionality is demonstrated through a hypothetical vaccine. METHODS: The MVM has three modules: supply and demand forecast; public health impact; and implementation cost and financing requirements. These modules include pre-entered reference data and also allow for user-defined inputs. The model includes an integrated sensitivity analysis function. Model functionality was demonstrated by estimating the public health impact of a hypothetical pre-erythrocytic malaria vaccine with 85% efficacy against uncomplicated disease and a vaccine efficacy decay rate of four years, based on internationally-established targets. Demand for this hypothetical vaccine was estimated based on historical vaccine implementation rates for routine infant immunization in 40 African countries over a 10-year period. Assumed purchase price was $5 per dose and injection equipment and delivery costs were $0.40 per dose. RESULTS: The model projects the number of doses needed, uncomplicated and severe cases averted, deaths and disability-adjusted life years (DALYs) averted, and cost to avert each. In the demonstration scenario, based on a projected demand of 532 million doses, the MVM estimated that 150 million uncomplicated cases of malaria and 1.1 million deaths would be averted over 10 years. This is equivalent to 943 uncomplicated cases and 7 deaths averted per 1,000 vaccinees. In discounted 2011 US dollars, this represents $11 per uncomplicated case averted and $1,482 per death averted. If vaccine efficacy were reduced to 75%, the estimated uncomplicated cases and deaths averted over 10 years would decrease by 14% and 19%, respectively. CONCLUSIONS: The MVM can provide valuable information to assist decision-making by vaccine developers and policymakers, information which will be refined and strengthened as field studies progress allowing further validation of modeling assumptions.


Assuntos
Vacinas Antimaláricas/administração & dosagem , Malária/epidemiologia , Modelos Estatísticos , Saúde Pública/métodos , África , Humanos , Malária/economia , Malária/prevenção & controle , Vacinas Antimaláricas/economia , Saúde Pública/economia , Anos de Vida Ajustados por Qualidade de Vida , Vacinação/economia
3.
Glob Public Health ; 7(9): 931-45, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22783872

RESUMO

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. Establishing target product profiles (TPPs) is a critical, early step towards tailoring interventions to suit both of these constituencies. Specific analyses can help identify and establish relevant TPP criteria such as optimal formulation, presentation and packaging. Clinical trials for a new intervention should be designed to address both TPP-specific questions and anticipated use of the intervention in target countries. Examples are provided from research on malaria vaccines that are also applicable to other new public health interventions.


Assuntos
Ensaios Clínicos como Assunto , Serviços de Saúde Comunitária/organização & administração , Países em Desenvolvimento , Planejamento em Saúde/organização & administração , Projetos de Pesquisa , Tomada de Decisões Gerenciais , Humanos , Programas de Imunização , Formulação de Políticas
4.
Infect Immun ; 77(1): 414-8, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19001073

RESUMO

Infection with Plasmodium berghei is lethal to mice, causing high levels of parasitemia, severe anemia, and death. However, when mice are treated with antimalarial drugs during acute infection, they have enhanced immunity to subsequent infections. With this infection and cure model of immunity, we systematically examined the basis of adaptive immunity to infection using immunodeficient mice. In order to induce adaptive immunity, mice were infected with blood-stage parasites. When the mice developed 2 to 3% parasitemia, they were treated with chloroquine to cure the infection. These convalescent mice were then challenged with homologous blood-stage parasites. Immunized wild-type mice were able to control the level of infection. In contrast, mice lacking mature B cells and T cells were unable to control a challenge infection, indicating the critical role of lymphocytes in immunity to P. berghei. Furthermore, mice lacking secreted antibody were unable to control the level of parasitemia following a challenge infection. Our results indicate that secreted antibody is a requirement for immunity to P. berghei.


Assuntos
Anticorpos Antiprotozoários/imunologia , Malária/imunologia , Plasmodium berghei/imunologia , Animais , Linfócitos B/imunologia , Imunização , Imunização Passiva , Malária/prevenção & controle , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Parasitemia/imunologia , Linfócitos T/imunologia
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