پرنيان فرخ نژاد

Covid-19 vaccines have been developed at an accelerating pace worldwide. However, the proper distribution of vaccines remains one of the key challenges faced by many developing countries. Therefore, it is essential to design an efficient vaccine supply chain network and develop an effective plan for vaccine procurement and distribution to reduce the Covid-19 vaccine shortage during the pandemic. In this study, a two-phase ordering-allocation approach under uncertainty is proposed for various types of Covid-19 vaccine supply chains. This approach involves ordering Covid-19 vaccines from domestic and international suppliers using an interval-based ordering system and allocating vaccines to different immunization stations while considering congestion. In the first phase, a rolling horizon ordering model is developed to place orders for different Covid-19 vaccines from various suppliers under uncertainty. In the second phase, the number of vaccines dispatched from cross-docking centers is allocated to regional immunization stations, taking into account allocation priorities and congestion. The uncertainty in vaccine production during the Covid-19 pandemic leads to an uncertain quantity of vaccines delivered to cross-docking centers. Furthermore, a rolling planning horizon approach is implemented in an iterative method to prevent vaccine shortages. To validate the ordering-allocation approach, a case study based on data from the Central Province, Arak city, was examined, and sensitivity analysis was performed on the model parameters. The results of adopting and not adopting the rolling planning horizon approach were compared. Additionally, the performance of the fuzzy chance-constrained method was eva‎luated by comparing it with a deterministic model. The results indicate that implementing the rolling planning horizon approach and fuzzy chance-constrained methods enhances network performance against operational risks, including the Covid-19 crisis. Moreover, applying the rolling planning horizon approach reduces costs and vaccine shortages in the second phase.

زنجيره تامين واكسن , همه‌گيري بيماري كوويد-19 , برنامه‌ريزي افق غلتان , سيستم موجودي , عدم قطعيت

vaccine supply chain , COVID-19 pandemic , rolling planning horizon approach , Inventory system , uncertainty

Parniyan Farrokhnezhad

Dr. Hosseini Motlagh