Objective: To assess the effectiveness of a volunteer-driven outreach program on immunization rates in children younger than 2 years.
Design: Randomized controlled trial.
Setting: Pediatric ambulatory clinics in New York, NY.
Patients: A total of 163 children were randomly assigned to receive services from the volunteer-driven outreach program or to serve as control subjects. All children were (1) younger than 2 years, (2) no-shows for a scheduled appointment in the pediatric clinic, and (3) due or overdue for a vaccine.
Intervention: Immunization outreach, tracking, and follow-up were provided by community volunteers throughout follow-up (mean, 6.5 months). Control children were notified of immunization status at enrollment but received no further contact until the conclusion of follow-up (mean, 6.4 months).
Main outcome measure: Immunization status 6 months after enrollment.
Results: Significantly more intervention children were up-to-date with their vaccination series than controls (75% vs. 54%; P = .03). Children in the control group were 2.8 times more likely to be late for a vaccine than intervention children (odds ratio = 2.8; P = .02). In addition, an immunization delay of longer than 30 days at enrollment was a significant predictor of final immunization delay (odds ratio = 2.6; P = .02).
Conclusions: This volunteer-driven program significantly improved immunization rates among intervention children compared with controls. Results confirm previous findings that indicate an increased risk of an incomplete immunization series by 2 years of age among children who fall behind early in their primary vaccination series. However, control children were almost 3 times more likely to be late (for > or =1 vaccines) than intervention children, regardless of whether an earlier immunization delay was present.