Objective: To determine increases in immunization up-to-date (UTD) rates at a rural pediatric practice with the sequential addition of records from other sites in a 2-county region.
Design/methods: UTD rates for children aged 3 months to 35 months (n = 876) were determined for the index practice and then recalculated after sequential addition of records from 1) the other private practice in the region, 2) 7 public primary care sites, and 3) 2 public health clinics in the region.
Results: Adding records from all sites increased documented UTD rates in the index practice from 49% to 64% at 3 months (N = 33, P = 0.025), 50% to 68% at 5 months (N = 38, P = 0.008), 28% to 45% at 7 months (N = 113, P <.01), 29% to 54% at 12 months (N = 200, P <.001), 11% to 35% at 19 months (N = 124, P <.001), and 10% to 33% at 24 months (N = 368, P <.001).
Conclusions: Regional registries will be valuable tools for immunization delivery if there is an ongoing commitment to effective collection of current and historical immunization data.