The Humanitarian Buffer is a mechanism established within the COVAX Facility to act as a measure of ‘last resort’ to ensure access to COVID-19 vaccines for high-risk and vulnerable populations in humanitarian settings. Populations of concern in humanitarian settings may include refugees, asylum seekers, stateless persons, internally displaced persons, minorities, populations in conflict settings or those affected by humanitarian emergencies, and vulnerable migrants irrespective of their legal status. Both COVAX Participants and humanitarian agencies can apply for Humanitarian Buffer doses.