Immunization is critical to saving children from infections. To increase vaccination coverage, valid and
real-time data are needed. Accordingly, it is essential to have a good report system that serves as defaulter tracking to
prevent children’s immunization failure. The Daerah Istimewa Yogyakarta (DIY) Health Office introduced an electronic
immunization registry and successfully implemented it for more than five years. It is the only individual-based record
system in Indonesia that has been sustainably operated for a long time. Yet, no systematic assessment of this system
has been conducted to date. This study examines the Sistem Informasi Imunisasi Terpadu (SIMUNDU) introduction
and implementation process with a view to extracting lessons that could inform scalability and sustainability across
the country
