Legislative mandates require the sharing of immunization information among multiple stakeholders. This in turn requires the implementation of interoperable systems across various information systems. A key challenge to system interoperability is the need to integrate healthcare information and processes across different settings. This paper reports work in progress on the development of a student immunization Health Information Exchange (HIE). The system builds on a commercially available platform, appropriately modified on both front and backend, to meet the needs of school health professionals and other stakeholders involved in the production and maintenance of immunization information. We describe the situated change perspective as well as the iterative and incremental development process adopted for the project, and examine some of the lessons learned throughout.