Markov Decision Process Models for Optimizing Vaccine Administration

该奖项的研究目标是制定和分析马尔可夫决策过程模型，使疫苗临床医生能够以最佳方式平衡疫苗管理固有的权衡，特别是在偏远地区，如农村地区和发展中国家。主要的权衡是疫苗“浪费”和错过疫苗接种机会之间的权衡。对于包装在大型多剂量瓶中的疫苗来说，浪费尤其严重，这些疫苗一旦打开，必须在几小时内使用；因此，临床医生面临着艰难的权衡，是打开小瓶来满足潜在的小即时需求，还是保留小瓶来满足潜在的大未来需求。此外，由于发展中国家偏远地区的电力供应往往不可靠，因此正在考虑开发一种被动冷藏箱，只要不经常打开，这种冷藏箱可以保持几个星期的温度；临床医生决定何时从这些冷藏箱中取出小瓶将面临艰难的权衡，是取出小瓶以供可能立即使用，还是在面对未来需求时没有疫苗可用。此外，这些冷箱的设计规范是悬而未决的问题，这在很大程度上取决于它们的使用将如何影响现场的浪费和覆盖范围。本研究的预期结果包括：(i)针对不同情况（如疫苗类型、小瓶大小、需求概况）作为许多变量（如一天中的时间、小瓶库存、冷箱打开历史）的函数的最佳疫苗管理政策（如，开瓶决策和冷箱检索决策）；（ii）传播外勤临床医生易于实施的操作指南；（三）对疫苗覆盖率和浪费方面的各种冷箱设计的见解。研究结果将通过世卫组织网站在美国国内和国际上传播，并有可能使全世界每年额外接种数百万种疫苗。

The research objective of this award is to formulate and analyze Markov decision process models to enable vaccine clinicians to optimally balance the tradeoffs inherent to vaccine administration, especially in remote locations, e.g., rural areas and developing countries. The main tradeoff is one between vaccine "wastage" and missed opportunities for vaccine administration. Wastage is especially acute for vaccines that are packaged in large, multi-dose vials which once opened, must be used within a matter of hours; hence clinicians face difficult tradeoffs between opening a vial to satisfy a potentially small immediate demand, versus retaining the vial to satisfy a potentially large future demand. Furthermore, because the power supply in remote areas of developing countries is often unreliable, the development of -passive cold boxes- that maintain temperature over several weeks - provided they are not opened excessively often is being considered; clinicians deciding when to retrieve vials from these cold boxes will face difficult tradeoffs between retrieving vials for potential immediate use, versus not having vaccines available in the face of future demand. Moreover, the design specifications for these cold boxes are open questions that depend heavily on how their use will impact wastage and coverage in the field.Anticipated outcomes of this research include: (i) optimal vaccine administration policies (e.g., vial opening decisions and cold box retrieval decisions) for different situations (e.g., vaccine type(s), vial size(s), demand profile(s)) as a function of many variables (e.g., time of day, vial inventory, history of cold box openings); (ii) dissemination of operational guidelines that can be easily implemented by clinicians in the field; and (iii) insights into various cold box designs in with respect to vaccine coverage and wastage. The results of the research will be disseminated within the US and internationally through the WHO website and potentially enable millions of additional vaccines to be administered annually throughout the world.