COVID-19 aşılama sürecinde gerçekleşen aşı israfının yanal aktarma ile önlenmesi

After the discovery and production of vaccines for the immunization against COVID-19 pandemic, mass vaccination programs are launched across the world. One of the main challenges faced during the COVID-19 mass vaccination programs is vaccine wastage. In a preliminary and empirical work conducted with healthcare professionals working at family health centers, we identify that using multi-dose vaccine vials is one of the significant factors causing the wastage. Some COVID-19 vaccines are preserved in multi-dose vials, and once a vial is opened, doses inside perish and go to waste in a few hours if not used. In this study, we analyze the lateral transshipment strategies in which open vials are transferred between vaccination points to decrease vaccine wastage. Besides making operational decisions regarding the vaccination process, we also examine the demand uncertainty issue due to the appointment no-shows. The problem is formulated as a 2-stage stochastic programming model. We solve the problem by developing a heuristic approach in which we cluster the vaccination points to form alliances using a mathematical model and utilizing the second stage of the 2-stage stochastic programming model. We validate our work by conducting a case study with family health centers in Tuzla, İstanbul and provide valuable insights for the case. The results show that our heuristic approach can be relied on its reasonable solution time, and provide quality solutions.