Age and sex specific spatiotemporal dynamics of malaria in Assam from 2011 to 2023

India aims to eliminate malaria by 2030, a goal that depends on controlling the disease in its remaining hotspots. The northeastern region of India, with its complex ecology, international borders, and diverse population distribution, is one of the most critical challenges for controlling malaria. Understanding exactly where and to whom malaria transmission persists is essential for effective, targeted control. This study conducted a detailed spatio-temporal analysis of malaria across Assam from 2011 to 2023. Bayesian spatial–temporal modelling and space–time scan statistics modelling were implemented, and the analysis mapped changing risks and identified significant clusters of malaria outbreaks. The work was specifically designed to compare risk across three key age groups: children under five, school-aged children (5–14 years), and adults (> 15 years). During the study period, malaria incidence declined in Assam, with persistent transmission concentrated in specific districts and age groups. School-aged children had the highest reported case incidence, with some areas showing more than 21 times the number of expected cases, marking it as an endemic for the disease. Persistent high-risk hotspots were identified in the central hills (Karbi Anglong, Dima Hasao) and western border districts with Bhutan (Kokrajhar, Chirang, Udalguri). These hotspots are surrounded by dense forests, tribal communities, and limited healthcare services. This study concludes that malaria in Assam is now a focal disease, concentrated in specific geographic and demographic pockets. Eliminating the disease will require a strategic shift away from state wide approaches toward targeted interventions that specifically address the high transmission among school-aged children in these forested and border districts.