BackgroundIndia became the first country in the WHO South-East Asia Region (SEAR) to introduce the rotavirus vaccine (RVV) in the Universal immunization programme (UIP) in 2016 with nationwide expansion by 2019. It was a landmark move to reduce the diarrheal disease burden in under-five children. To assess the implementation process of introduction of RVV, Post Introduction Evaluation (PIE) was conducted in March 2022. MethodsThe evaluation was conducted across 14 states, 28 districts and 28 health facilities to obtain a nationwide geographical inclusion. Stakeholders involved in program decision-making, planning, training, vaccine delivery, logistics, and communication from all levels (National, state, district, health facility, health worker, caregiver) were interviewed using standardized data collection tool for PIE (adapted from the standard WHO PIE questionnaire) and scripted on a digital tool. ResultsA total of 260 interviews were conducted. Political willingness, well-planned preparedness activities, securing vaccines timely, strong supply chain monitoring, availability of domestic RVV products, quality trainings and intense communication activities were the key factors identified for the successful RVV introduction. Key activities during the introduction included cold chain space assessment, trainings of healthcare workforce, dissemination of job aids, updation of recording & reporting formats and strengthening of AEFI surveillance. Lack of community awareness for immunization in a few areas, fear of AEFI amongst some caregivers and local issues with Alternate Vaccine Delivery (AVD) were some reported challenges in achieving high coverage for RVV. ConclusionsOverall, the nationwide roll-out of RVV was smooth and the vaccine has been well-accepted in the community. The assessment emphasizes on having a well-strategized operational and communication planning, which is very crucial for any new vaccine introduction.