The Uncertain Times of COVID Mass Vaccine Deliveries: from Start-up to Steady-State

Mass vaccination campaigns have been adopted throughout the world as a major tool to stop the spread of COVID or at least abate its lethal consequences. Smart vaccination strategies have been proposed to make the most efficient use of the scarce resources (e.g., medical and nursing staff) and achieve vaccination aims (i.e., vaccinating as many people as possible in the shortest possible time). However, smart strategies may fail if vaccine deliveries are erratic or do not exhibit even statistical regularity. In this paper, we perform a statistical analysis of up-to-date vaccine delivery data to uncover regularities and use them to draw a probabilistic model of vaccine deliveries that may help optimize and evaluate smart vaccination strategies. We find that for two out of three vaccine manufacturing companies, deliveries concentrate on one or at most two days over a week, though the actual day may be modelled by an arithmetic distribution.