Abstract: IMapp, the Immunization App, was developed to strengthen the delivery of public health services, taking advantage of an innovative multidisciplinary approach and digital technologies like Geographic Information Systems (GIS), Remote Sensing (RS) and Machine Learning (ML). The initiative demonstrated the suitability of porting public health data on a GIS platform to get good insights into the distribution of vaccines; create an automated indexing system to monitor the efficacy of the Universal Immunisation Programme (UIP) on the ground, and geographically extend vaccination to include all rural population clusters. It was validated in the East Champaran district of Bihar, India, in the years 2019 and 2020, under the initiative Immunization Data: Innovating for Action, supported by Grand Challenges India.