During the COVID-19 pandemic, people in the most vulnerable situations were disproportionately exposed to SARS-CoV-2. Following the launch of the vaccination campaign, a survey conducted by the Field Epidemiology Unit of Doctors Without Borders (MSF) between June and December 2021 revealed vaccination rates lower than those of the general population. Barriers were identified, as well as favorable factors, leading the nongovernmental organization to recommend measures for improved comprehensive healthcare for populations living in extreme poverty.