Passive cold devices for vaccine supply chains

A major priority in many low and middle income countries is the eradication of infectious diseases through an effective vaccination program. However, the lack of reliable infrastructure, equipment and support often prove to be significant barriers in such countries. In particular, unreliable electric power and refrigeration equipment are major concerns and this has prompted research into the development of passive cold storage devices (PCDs) that are not dependent on electric power and can maintain cold temperatures for extended periods of time using a passive medium such as ice. The development of PCDs is in its early stages, and there are many open questions including how they should be sized, the interaction between price and device size, and how often they should be replenished. So far, these types of questions have not been systematically analyzed anywhere in the research literature, and this paper describes a model to address these issues in order to better guide the development of PCDs in the near future. This paper examines actual use cases with real data from a representative country, and presents a model that captures the various tradeoffs that must be considered in developing a suitable PCD while providing guidance on what would constitute a useful, robust and economical design.