paraphrase While these efforts have helped immunization programs achieve more functional standards, there is a need to shift focus from infrastructure and functionality improvements to high data quality through objective measurement of IIS performance and evaluating critical outcomes. Additionally, realizing the vision of a nationwide repository of high-quality immunization data requires tackling the many challenges that impact data quality and availability including those related to policy, data sharing, data use, aging IIS technology, sustainability, and participation in the IIS. This paper describes the current state of IIS in the United States, critical challenges impacting the quality of data in IIS, and potential components of a future IIS model to address these challenges