Validation of a regional immunization registry utilized in a pediatric emergency department

Study objectives: We measure the accuracy of data in a regional immunization registry used when patients aged 6 years and younger present to a university pediatric emergency department (ED). Methods: This was a prospective cohort study. From October 1, 2002, to March 31, 2003, all patients aged 2 months through 6 years and registered for care in the pediatric ED were screened for their participation in the immunization registry after their pediatric ED visit was completed. The rate of participation in the immunization registry was measured, and the patientʹs immunization status on the pediatric ED visit date (as reported by computerized immunization registry) was reported according to current guidelines of the Advisory Committee on Immunization Practices. In patients found not up to date (NUTD), a second inquiry of the immunization registry 8 weeks after their visit date was completed, and the number of additional patients found up to date (UTD) was measured. Contact with the primary care physician (PCP) was also made to verify the accuracy of the immunization registry patientʹs status as NUTD by the immunization registry for the screening date. Results: Of 4,628 eligible patients treated in the pediatric ED, 1,219 (26%) were enrolled in the immunization registry. Of these, 466 (38%) were UTD. The 8-week second inquiry of the immunization registry identified 55 (5%) more as UTD, totaling 521 (43%). PCP verification identified an additional 301 (25%) totaling 822 (67%) actually UTD, resulting in 274 (22%) that were NUTD. One hundred fifty-nine (53%) of the 301 ultimately verified UTD patients with PCP contact were a result of delayed data entry by the PCP, whereas 142 (47%) were due to data error. The PCP office was unwilling to verify data in 123 patients, citing lack of time or concerns over patient confidentiality as the main reasons. Conclusion: In this study, approximately one quarter of pediatric ED patients were enrolled in the regional immunization registry, of whom 274 (22%) patients were not up to date. The immunization registry can be used in conjunction with a pediatric ED visit to identify underimmunized patients. Reducing data entry delays and errors may enhance accuracy of the immunization registry at pediatric ED visit and ultimately help to improve immunization rates.