Fig. 1.

Problem definition: On each day, available vaccines need to be distributed from cooler storage to the $VCs$ within a certain time window ($T{W}_{da{y}_n}$). On $da{y}_{1+k}$, people who have already received the first dose will become top priority to receive the second dose of vaccine. Each $VC$, based on type, has specific service capacity. The plus symbols indicate the locations of the $VCs$, and the black dots indicate the locations of people. The black dots show the population who are waiting to receive their first vaccination dose. The red dots indicate the high priority demands in each suburb assigned for receiving their first dose of the vaccine. The green dots indicate people who are due to receive the second dose of vaccination on the day. The grey coloured dots show the people who have received both doses of vaccine. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)