Currently vaccines protecting from COVID-19 are a scarce resource. Prioritising vaccination for certain groups of society is placed in a context of uncertainty due to changing evidence on the available vaccines and changing infection dynamics. To meet accepted ethical standards of procedural justice and individual autonomy, vaccine allocation strategies need to state reasons for prioritisation explicitly while at the same time communicating the expected risks and benefits of vaccination at different times and with different vaccines transparently. In this article, we provide a concept summarising epidemiological considerations underlying current vaccine prioritisation strategies in an accessible way. We define six priority groups (vulnerable individuals, persons in close contact with the vulnerable, key workers with direct work-related contact with the public, key workers without direct work-related contact to the public, dependents of key workers and members of groups with high interpersonal contact rates) and state vaccine priorities for them. Additionally, prioritisation may follow non-epidemiological considerations including the aim to increase intra-societal justice and reducing inequality. While national prioritisation plans integrate many of these concepts, the international community has so far failed to guarantee equitable or procedurally just access to vaccines across settings with different levels of wealth.