Background: Reminder-recall interventions have improved immunization rates in numerous studies.
Objective: To evaluate the impact of large-scale, registry-based reminder-recall interventions on low immunization rates in an inner-city population.
Design: Randomized, controlled, effectiveness trial.
Setting: Fulton County, Georgia.
Participants: A total of 3050 children (76% black, 14% Hispanic, 7% white, and 3% other or unknown; median age, 9 months; range, 1-14 months) identified in an immunization registry as receiving health care in the public sector.
Interventions: Each child was randomly assigned to 1 of 4 groups: control (usual care), autodialer (automated telephone or mail reminder recall), outreach (in-person telephone, mail, or home visit recall), and combination (autodialer with outreach backup). Interventions continued until the child reached 24 months of age.
Main outcome measure: Completion by the age of 24 months of the 4-3-1-3 vaccination series based on intention-to-treat analysis.
Results: A total of 260 (34%) of the 763 patients in the control group, 306 (40%) of the 763 in the autodialer group, 284 (37%) of the 760 in the outreach group, and 293 (38%) of 764 in the combination group completed the vaccination series.
Conclusion: Large-scale, registry-based reminder-recall interventions produced only small improvements in low immunization rates of an inner-city population.