Optimal Design and Operation of WHO-EPI Vaccine Distribution Networks

针对疫苗可预防疾病的第一个系统的全球运动是世界卫生组织于1974年发起的扩大免疫规划（EPI）。2000年，全球疫苗和免疫联盟（免疫联盟）成立，专门将扩大免疫方案扩大到世界上最贫穷的国家。尽管作出了这些努力，但传染病仍然是一个严重的全球性问题，世界各地低收入和中等收入国家的数百万儿童仍然面临通过免疫接种可预防的疾病的风险。虽然较贫穷国家缺乏资源肯定会导致疫苗可预防的死亡，但许多问题可归因于与世卫组织-扩大免疫方案疫苗分销链的设计和运作方式有关的浪费和效率低下。几乎每个国家的分销网络的基本结构及其运作都是相同的，几乎没有人考虑过沿着其他现代供应链网络的路线从根本上重新设计分销网络。该奖项支持通过建立和优化世卫组织-扩大免疫方案疫苗分发网络的详细数学模型来解决这一关键问题的基础研究。拟议的研究将提供替代方案，从根本上改变拯救生命的疫苗在世界各地的分发和管理方式，从而造福社会。它有可能提高疫苗分销网络的效力，并使世界各地每年能够额外接种数百万疫苗，从而降低公共卫生费用并挽救生命。一个典型的EPI网络被设计成一个四层（或者偶尔，三层或五层）层次结构，具有从单个源节点发出的严格树状流。网络由来自网络中节点子集的流补充，以表示到远程位置的临时外展会话。本研究将开发数学规划模型，以(1)允许任何类型的流动（而不仅仅是严格的树木流动），同时也能够纳入任何特定领域对流动的限制；(2)在供应链冷库和运输资源的背景下考虑疫苗流动；(3)允许在设计中采用特定国家的操作政策；(4)考虑补充静态免疫设施的外展活动。所提出的网络和整数规划模型将捕捉到疫苗管理中固有的独特目标、权衡和限制。这些模型不仅仅是现有理论的应用，而是将一般供应链网络设计文献的新颖扩展到疫苗分销网络的独特领域。

The first systematic worldwide campaign against vaccine-preventable diseases was the Expanded Program on Immunization (or EPI), started in 1974 by the WHO. In 2000, the Global Alliance for Vaccines and Immunization (GAVI) was launched specifically to extend the EPI program to the poorest countries in the world. Despite these efforts infectious diseases remain a grave, global concern and millions of children in low and middle income countries around the world remain at risk for diseases preventable via immunization. While a paucity of resources in poorer countries certainly contributes to vaccine-preventable deaths, many of the problems can be attributed to waste and inefficiencies associated with how the WHO-EPI vaccine distribution chains are designed and operated. The basic structure of the distribution network and its operation in virtually every country is identical and almost no thought has been given to fundamentally redesigning the distribution networks along the lines of other modern supply chain networks. This award supports fundamental research to address this critical issue by building and optimizing detailed mathematical models of the WHO-EPI vaccine distribution network. The proposed research will benefit society by providing alternatives that could fundamentally transform the way life-saving vaccines are distributed and administered around the world. It has the potential to improve the efficacy of vaccine distribution networks and enable millions of additional vaccinations annually around the world, resulting in reduced public health costs and saved lives.A typical EPI network is designed as a four- (or occasionally, three- or five-) level hierarchical structure with strictly arborescent flows emanating from a single source node. The network is supplemented by flows from a subset of nodes in the network, to represent ad hoc outreach sessions to remote locations. This research will develop mathematical programming models to (1) permit any type of flow (rather than just strictly arborescent flows), while also being able to incorporate any domain-specific constraints on flow, (2) consider vaccine flows in the context of supply chain cold storage and transportation resources, (3) allow for country-specific operating policies to be adopted into the design, and (4) account for outreach activities that supplement static immunization facilities. The proposed network and integer programming models will capture the unique objectives, tradeoffs and constraints inherent in vaccine administration. The models are not simply an application of existing theory, but rather, novel extensions of the general supply chain network design literature to the unique domain of vaccine distribution networks.