The purpose of this Request for Proposals (RFP) is to enter into a contractual agreement with a successful bidder and select a suitable contractor to conduct a study to better understand good practice as well as challenges faced on the equitable deployment and administration of COVID-19 vaccines to reach populations of concern in humanitarian settings as well as understand measures taken to mitigate impact on essential health services including routine immunisation. The deadline for submitting proposals has been extended to 12 January 2022. Proposals should be sent via email at healthcluster@who.int.