THE IMPACT OF THE CHANGE TO IPV ON THE IMMUNIZATION STATUS OF CHILDREN IN THE UNITED STATES: A STUDY FROM PROS AND THE NATIONAL MEDICAL ASSOCIATION (NMA) JA Taylor, PM Darden, DA Brooks, AE Baker. Pediatrics, University of Washington, Seattle, WA; Pediatrics, Medical University of South Carolina, Charleston, SC; Pediatrics, Johns Hopkins University, Baltimore, MD; and Pediatric Research in Office Settings (PROS), Center for Child Health Research, American Academy of Pediatrics, Elk Grove Village, IL. Presented as a poster symposium at the 2000 Pediatric Academic Societies? Annual Meeting.

OBJECTIVE: To determine if the change from an all-OPV immunization schedule to a schedule that contains IPV has had negative consequences on the immunization status of young children.

DESIGN/METHODS: Immunization data were collected from the medical records of children 8-35 months old seen consecutively in the offices of practicing pediatricians who were members of the PROS network and the NMA. Data on up to 120 eligible children were collected in each practice. Children were considered to be fully immunized at 8 months of age if they had received 3 DTP, 2 Hib, 2 Hepatitis B, and 2 polio vaccines, and fully immunized at 12 months if they had received 3 DTP, 2 Hib, 3 Hepatitis B, and 2 polio vaccines. Patients were classified as being in either the IPV or OPV group based on the initial type of immunization received. Logistic regression was used to calculate the odds ratios (ORs) of IPV use as a predictor of immunization status at 8 and 12 months of age, after adjusting for ethnicity, maternal education level and method of payment for vaccines. The effect of clustering into practices was adjusted for by the use of Generalized Estimating Equation techniques. Similar analyses were performed to determine if the type of immunization used was associated with delay in receiving the first and/or second dose of polio vaccine.

RESULTS: Data were analyzed on 7165 children from 76 practices in 36 states; 79.4% of patients were fully immunized at 8 months of age and 74.5% of those eligible at 12 months. A total of 3995 patients were in the OPV type was undetermined. Compared to the OPV group, adjusted Ors for IPV as a predictor of being fully immunized at 8 and 12 months were 1.19 (95% CI 1.02,1.38) and 0.96 (95% CI 0.78,1.18), respectively. The adjusted OR for IPV as a predictor of receiving the first dose of polio vaccine in a timely manner was 0.99 (95% CI 0.80,1.22); the OR for the second dose was 1.01 (95% CI 0.80,1.27).

CONCLUSION: The results of this national study strongly indicate that the use of IPV has had no negative effects on the overall immunization status, or timeliness of polio vaccination in young children.