To the Editor.
—We were pleased with the overview of immunization registries, or immunization information systems (IIS), by Mr Gostin and Ms Lazzarini.1 However, several points raised by the authors require clarification.According to the article, "national data systems that can track all children and identify those who need to be vaccinated do not exist." While such a national system has been proposed,2 state and local data systems were selected because immunizations are provided to persons in the community by local health departments and other private and public health care providers. Therefore, to accommodate local situations and preferences, IIS are most efficiently developed by state and local health departments. Developing IIS requires a great deal of collaboration among health departments, private providers, local volunteer and professional organizations, and many others. These collaborations can best be developed at the community level. Community-based IIS can fulfill the basic purposes of