Redesign of vaccine distribution networks

Abstract

In most low and middle income countries supported by the World Health Organization's Expanded Programme on Immunization, vaccines are distributed through a legacy medical supply chain that is typically not costefficient. Vaccines require storage and transport in a temperature controlled environment; this requires a "cold" distribution chain with capacity constraints on cold storage and cold transport. We propose an approach to redesigning the vaccine distribution chain that includes locating a set of intermediate distribution centers and determining the flow paths from the central store (where vaccines are received into a country) through one or more of these to health clinics where vaccination actually occurs. In addition, the transport vehicles to allocate to each flow path, and the cold storage devices to use at each clinic or intermediate distribution center are determined. The redesigned network does not have to follow the current four-tiered, arborescent structure commonly found in practice but can use alternative network structures. To redesign this network optimally, we develop a mixed-integer programming model that can be used for small to medium sized problems and also present a hybrid heuristic-MIP method to obtain good solutions for larger problems. Numerical results are shown using data reflecting distribution networks in several countries in sub-Saharan Africa.

A light‐touch routing optimization tool (RoOT) for vaccine and medical supply distribution in Mozambique

“…The geography of many low‐income countries, such as the lack of proper roads or transportation methods to reach populations in need (Chan et al., 2013), is an important factor. In addition, current distribution respects political boundaries (Lim et al., 2019). Therefore, it is important to understand this type of humanitarian logistics problem and adapt how other fields achieve efficient distribution under these conditions.…”

“…The problem considered in this paper includes capacity constraints on the vehicles and can be formulated as a capacitated VRP (CVRP) (Laporte et al., 2002). The need of a cold chain is also an important aspect to consider in vaccine distribution (Lim et al., 2019). Vaccines are perishable and inappropriate refrigeration outside of ideal storage temperatures results in waste (Comes et al., 2018).…”

Continuous Genetic Algorithms in the Optimization of Logistic Networks: Applicability Assessment and Tuning

“…Their control law is an improvement over the OUT policy with respect to demand variance smoothening in the markets that are subjected to significant fluctuations. Recent publications in this category target mostly real-life cases where arborescent models may be applied [37]. However, in the face of globalization, modern logistic systems are organized into mesh-type topologies with arbitrary interconnection architectures.…”

The Generalized Median Tour Problem: Modeling, Solving and an Application

“…The objective function (1) jointly minimizes the distance of the tour plus the access distance to the tour. Constraints (2) and 3force the route to a single visit per cluster. Constraints (4) state the flow balance to each node.…”

“…Hence, the number of stops or transfer stations should be reduced (crossdocking or intermediate facilities). Simultaneously, special and expensive transportation modes are usually required (e.g., airplanes, ambulances, and special trucks), which provide proper conditions inside the vehicles, including cooling, security, and stability [1,2,3]. This issue is particularly relevant and challenging for geographically isolated rural areas in undeveloped and developing countries, given the limited, or even rudimentary nature of their local transportation systems.…”