Every year millions of people are vaccinated preventively: they receive the annual influenza shot, are included in childhood immunization programs, or are vaccinated against other infectious diseases. Preventive vaccination takes place before a disease emerges and aims at preventing a disease outbreak. Besides preventive vaccination, reactive vaccination can take place during an outbreak of an infectious disease or in response to a bioterror attack. Although vaccination is a medical intervention, successful vaccination campaigns are impossible without good logistics. The importance of vaccine logistics is demonstrated by the growing number of studies on the subject. In this paper, we structure the literature on vaccine logistics, using the priority areas defined by the World Health Organization (WHO) (World Health Organization & PATH, 2011). These priority areas allow us to evaluate the current state of research on the vaccine supply chain and to identify promising directions that could be further explored to create a flexible and robust vaccine supply chain. We focus on the first three priorities of the WHO, as these are most related to Operations Research/Operations Management (OR/OM):

• Products and packaging

• Immunization supply system efficiency

• Environmental impact of immunization supply systems