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[Optimize.WHO]

Modeling tools under development

by Tessa Tan-Torres, WHO; Linda Allain, USAID | DELIVER PROJECT; Bruce Lee, University of Pittsburgh; and Carol Levin, PATH

If developing countries are to meet their populations’ health needs, they must ensure that their supply chains are able to cope with the increased quantities, volumes, and cost of supplies. To help decision-makers understand the possible health and/or cost impacts of various supply chain design options, four different health commodity supply chain modeling initiatives are underway: (1) the logistics module of the Unified Health Model (UHM) sponsored by the United Nations (UN) Interagency Working Group on Costing, (2) the 2020 Supply Chain Model (USAID | DELIVER PROJECT), (3) the Vaccine Modeling Initiative (VMI) through the University of Pittsburgh, and (4) the vaccine logistics model at PATH-World Health Organization (WHO) with project Optimize. With the desire to demystify these four different yet complementary initiatives, this article explains the purpose, application, and expectations for each model.

The UHM is a tool for national planners to facilitate their strategic planning process. The model can be used to generate scenarios that display the financial requirements and expected mortality impact arising from alternative combinations of strategies. Its modules relate to key parts of the health system and major diseases and conditions, with particular focus on the health-related millennium development goals. The logistics module covers scenarios related to health logistics and supply chain. This module is being developed by LLamasoft using a simplified version of their “Supply Chain Guru” software package. The specific goal for this module is to take a forecast of commodity and logistic equipment requirements and basic product information and, taking into account the country context generate a supply chain network, logistics metrics, financial metrics, and measures of network service. Individual modules of the UHM will be piloted in third quarter 2010. The full model will be piloted in 2011 and then will be publicly available with full documentation and opportunities for training.

The 2020 Supply Chain Model is an activity undertaken by the USAID | DELIVER PROJECT in collaboration with other partners. The model will work from a “country view” in terms of morbidity patterns and the products required to meet treatment and prevention of prevailing diseases, as well as product needs for other public health initiatives such as family planning services, in the years 2020 to 2025. The 2020 model is designed to help policymakers accurately visualize and understand the most likely and possible situations facing them in ten years and make informed decisions about how to design their supply chains to meet those needs. The model should be available in late June or early July 2010 with plans for dissemination in the fall of 2010.

The VMI, funded by the Bill & Melinda Gates Foundation and based at the University of Pittsburgh, aims to develop computer models and simulations to better understand vaccine development, distribution, and administration. The VMI is developing “HERMES,” an interactive computer software tool that can rapidly create a simulation model of nearly any vaccine supply chain to the level of detail specified by the user (ranging from very simple representations to an extensively detailed representation of each vaccine unit, person, storage container, transport device, etc.). This software tool will be freely available and will include a graphical user interface which will allow users to input different characteristics of the supply chain and vaccines. Within minutes HERMES can construct a simulation model of the supply chain and the vaccines flowing through the chain. HERMES will be able to either stand alone or dock with other models such as disease models to simulate the resulting effects on on the items of interest to the end user (e.g., disease control, personnel allocation, inventory management, ordering policies, budgetary impact, etc.). The tool is currently in the verification and validation stage using data from Niger’s Expanded Program on Immunization. VMI expects to release the software tool in 2011, along with documentation, training, and support to interested decision-makers.

Optimize is developing a vaccine supply chain logistic model in both Excel and ARENA^®, a logistics simulation software. The model is designed to provide a visual presentation of the transport, cold chain, and warehouse components of the vaccines and injections supply chain and provide a platform for simulating changes and evaluating the associated costs. The model can be applied to any country setting, capturing the multiple functions and levels of the vaccine logistic supply chain. For example, in Vietnam, Optimize is piloting the introduction of small-volume passive cooling devices at the commune level. By modeling the costs and health impacts of this change and comparing it to baseline costs and impacts, government collaborators will be able to understand comparative costs and benefits of the proposed change, inform decisions and policies relating to the change, and engage in future vaccine supply chain system designs. Optimize is also supporting the other modeling initiatives through direct collaboration and participation on technical advisory groups.

How do the models compare?

Above all, each of these modeling tools is being created to help decision-makers make informed choices about supply chain design and management options. The models can answer difficult questions, such as: What are the trade-offs between storage and warehousing for health commodities? What is the cost impact of expanding the volume of drugs and vaccines in the supply chain? What is the cost impact of different supply chain design scenarios that will improve access to health commodities in remote areas? A summary of the models and their differentiating characteristics is provided in Table 1. Although there is considerable overlap among the models, they each serve a slightly different purpose, and their developers are working together to ensure that unnecessary repetition or reinvention is avoided.

Table 1: Summary of the four models

Model	Scope	Target countries	Procurement?	Measured outputs	Software	Developers
UHM	All health commodities, including vaccines	Will be made publicly available	Yes	Cost and health impact	Simplified “Supply Chain Guru” by LLamasoft	UN Interagency Working Group on Costing and LLamasoft
2020 Supply Chain Model	All health commodities, including vaccines	Developing countries	Yes	Cost, resource requirements and system performance	Modifed “Supply Chain Guru” by LLamasoft	USAID | DELIVER PROJECT
VMI’s HERMES	Currently focused on vaccines and their accessories but can incorporate any product (e.g., medications)	Software tool that can be used to rapidly construct any supply chain in any country	Yes	Cost, health impact, and system performance (i.e., coverage, wastage, stock-outs, inventory levels, etc.,). Outputs are customizable by the end-user	Custom designed (developed in C++) with a customized graphical user interface	University of Pittsburgh and Pittsburgh Supercomputing Center
Optimize Supply Chain Model	Vaccines and temperature-sensitive drugs	Limited to project partners	No	Cost and system performance (i.e., coverage, wastage, stock-outs, etc.)	Microsoft Excel and ARENA®	Optimize, a WHO-PATH collaboration

 

Together, these four modeling initiatives provide countries systematic and complementary approaches to answer key questions about immunization and health systems for the future. To learn more about one of the modeling tools, please contact the organization directly:

Tessa Tan-Torres, WHO
Linda Allain, USAID | DELIVER PROJECT
Bruce Lee, University of Pittsburgh
Carol Levin, PATH

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