Environmental and social assessment of transport and cooling systems in last-mile cold-chain vaccine distribution: A case study in Flanders, Belgium

Although the discussions on the sustainability of transport and logistics have been a focus of research in recent years, the impacts of the choice of cooling systems within cold chains have not received the same attention. This paper assesses the environmental and social implications of cold-chain vaccine distribution in the last mile, in terms of CO2 emissions from cooling systems and transport, as well as the external costs of transport. The last-mile vaccine distribution is modelled using a strategic approach to perform multi-scenario analyses. An application within the Flemish immunisation programme in Belgium compares the performance of active (ACS) and passive (PCS) cooling systems during last-mile vaccine distribution. The CO2 emissions results indicate that PCS are the most efficient for multi-stop distribution, while ACS emissions rise sharply with more stops along the route. An illustrative example explores the potential environmental benefits of using cargo bikes and PCS for deliveries in the densest regions. Regarding social impacts, the urban distribution of vaccines presents the highest effects on the external costs categories of accidents, air pollution, and congestion. The findings are relevant to cold-chain planning for logistics operators, as the efficient implementation of cooling systems can enhance all dimensions of sustainability.