studies using NHIS data should provide analytic tools that can compensate for some of the limitations of telephone surveys.
The other activity that promises major improvements in immunization information is the development of immunization registries and tracking systems. Systems are being developed independently by commercial firms, individual providers, HMOs, communities, and some states. In addition, Congress is considering legislation that would provide federal funds to support the development of state registries, which would enhance the ability of states to define and respond to immunization needs among their populations.
The greatest value will be derived from systems that encompass all children and that are used by all providers. The committee sees merit in aiming for a national system of state-based registries. Registering children when they are born (or arrive in this country), as is done in the United Kingdom, ensures that the complete population of children will be known and that a child's immunization records can follow the child to any provider in any state.
In addition to computer-based registries and tracking systems, information tools such as family-held immunization records remain useful. They are an information resource for the family and can be used by providers to encourage families to take responsibility for having their children immunized. In some cases, registries can be used to generate records for a family's children.
At the same time that advances in technology are creating new opportunities to obtain, store, and use information on immunization services for children, changes in the ways in which vaccines are purchased are creating an incentive to have accurate information on the demand for vaccines. Because the Vaccines for Children Program will provide states with enough federally purchased vaccine to immunize Medicaid-eligible and uninsured children, states want to know the size of that population and the immunization status of those children. In the past, states played a larger role in purchasing vaccines for these groups, but financial constraints gave states little incentive to make accurate estimates of any increase in demand.
Clearly, immunization registries and tracking systems can help states with their vaccine accounting and public health assessments. These systems will also benefit children and their families by facilitating individualized outreach and follow-up. They can help providers identify those children who are due for immunizations and assess compliance with immunization guidelines. It must always be clear, however, that registries and other information systems are tools for improving immunization levels and not ends in themselves.