A passive cold storage device economic model to evaluate selected immunization location scenarios

Abstract

Background The challenge of keeping vaccines cold at health posts given the unreliability of power sources in many low- and middle-income countries and the expense and maintenance requirements of solar refrigerators has motivated the development of passive cold storage devices (PCDs), containers that keep vaccines cold without using an active energy source. With different PCDs under development, manufacturers, policymakers and funders need guidance on how varying different PCD characteristics may affect the devices’ cost and utility. Methods We developed an economic spreadsheet model representing the lowest two levels of a typical Expanded Program on Immunization (EPI) vaccine supply chain: a district store, the immunization locations that the district store serves, and the transport vehicles that operate between the district store and the immunization locations. The model compares the use of three vaccine storage device options [(1) portable PCDs, (2) stationary PCDs, or (3) solar refrigerators] and allows the user to vary different device (e.g., size and cost) and scenario characteristics (e.g., catchment area population size and vaccine schedule). Results For a sample set of select scenarios and equipment specification, we found the portable PCD to generally be better suited to populations of 5,000 or less. The stationary PCD replenished once per month can be a robust design especially with a 35L capacity and a cost of $2,500 or less. The solar device was generally a reasonable alternative for most of the scenarios explored if the cost was $2,100 or less (including installation). No one device type dominated over all explored circumstances. Therefore, the best device may vary from country-to-country and location-to-location within a country. Conclusions This study introduces a quantitative model to help guide PCD development. Although our selected set of explored scenarios and device designs was not exhaustive, future explorations can further alter model input values to represent additional scenarios and device designs.

Controlling Human Rabies: The Development of an Effective, Inexpensive and Locally Made Passive Cooling Device for Storing Thermotolerant Animal Rabies Vaccines

“…For example, the Arkteks ® PCD was used to deliver vaccines during the 2014–2015 Ebola outbreak in West Africa and in Nepal to assist in the immunization campaign after the 2015 earthquake [ 22 , 23 ]. However, despite their utility, the price of commercially manufactured PCDs is often very high, ranging from US$700 to 3000 per unit [ 15 ]. Some designs require substantial maintenance, for example the Arkteks ® and the Nano-Q ® PCDs whilst able to keep temperatures inside the vaccine compartment at refrigeration temperature for many days, require recharging with ice.…”

“…However, these refrigerators are costly to purchase and maintain, limiting their use [ 13 ]. Another generation of vaccine storage devices, passive cooling devices (PCDs) [ 14 , 15 ], do not require power (electric, solar or gas) to keep vaccines cool. Rather, PCDs use cooling media such as ice packs or water, and insulation to maintain a cool storage environment [ 10 ].…”

Using Simulation Modeling to Guide the Design of the Girl Scouts Fierce & Fit Program

“…For example, during the 2009 H1N1 influenza pandemic, computational simulation models helped national, state, and local decision-makers answer questions about whether to close schools, how antiviral medications should be used, and who should get vaccines first when vaccines were in short supply (21)(22)(23)(24)(25). Computational models have also helped decision-makers plan new vaccine introductions (26,27), determine how best to design vaccine-carrying devices (28,29), and determine how to redesign health product supply chains (30,31). The use of computational models to directly guide program design in other health areas is relatively new.…”

When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study

“…on-grid refrigerators, hereafter referred to as “electric refrigerators”) in various settings is important for decision makers to select the most appropriate cold chain equipment for their situation. Computational modeling can help elucidate the potential system-wide implications of changing one or more components in a supply chain prior to deciding whether to invest the resources necessary for implementation [ 8 ]. We used simulation modeling to evaluate the impact of SDDs on vaccine supply chain performance and costs under a range of circumstances and to determine the conditions necessary for solar powered storage equipment to be favorable over ILRs.…”