The World Health Organization (WHO), taking the lead in responding to this pressing issue, selected hera to conduct a study on the complexities of COVID-19 vaccine deployment and administration in humanitarian settings, with a specific focus on populations of concern (PoC). The study was initiated in March 2022 and concluded in March 2023, and encompassed case studies in multiple countries deeply affected by humanitarian crises: Cox's Bazar (Bangladesh), Colombia, the Democratic Republic of the Congo (DRC), Iraq, South Sudan, and Syria.