Well, you're halfway there. Each state already runs an immunization information system which holds this data. In Arizona, it's required that all immunizations

Well, you're halfway there. Each state already runs an immunization information system which holds this data. In Arizona, it's required that all immunizations given to <=18s are reported (along with "encouragement" for providers to report adult immunizations) and this is the basis for determining if the child may attend a public school, for example.