More than four million children are born each year in the United States. Each of these children should receive 14 to 15 doses of vaccines by their second birthday, and 16 to 18 doses by school entry.

Immunizations may be obtained from private physicians, public health clinics, hospitals, and a variety of other health services facilities. Approximately 95 percent of all U.S. children begin the recommended series of vaccinations, but only about 75 percent complete the series by 2 years of age-a critical period for childhood disease prevention. Approximately 40 percent of children receive their preschool immunizations from two or more facilities.

Ensuring that children complete the recommended series of immunizations at the appropriate time is the main problem facing immunization programs. However, since many children receive vaccines from more than one provider and since many parents do not maintain accurate records of their children’s immunizations, it is difficult to evaluate the immunization status of individuals. Without this information, efforts to identify and aggressively pursue children who are incompletely immunized are severely hampered.

To address this problem the National Immunization Program within the CDC has developed a set of guidelines for the development of systems or registries for the collection and assessment of immunization data. In addition, the CDC has given the states the objective of ensuring that at least 90 percent of children under the age of 2 and 95 percent of children under the age of 18 are adequately immunized. These guidelines were developed to address the areas that the CDC felt were the greatest obstacles to reach this objective, including:

• Incomplete records due to fragmentation of health care delivery
• Large and cumbersome files of paper records
• Difficulties in assessing immunization needs due to complex and dynamic immunization schedules

Major healthcare organizations, including the American Academy of Pediatrics, American Medical Association, American Osteopathic Association, the American Association of Health Plans and the American Public Health Association, have endorsed immunization registries as an important tool in the delivery of vaccine.