Factors Associated with Immunization Completion Among Infants of the Vaccines for Children Program

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D Delgado Jefferson School of Population Health, Thomas Jefferson University, Philadelphia, PA


The purpose of this study was to investigate factors associated with completion of an immunization series by 24 months of age in infants receiving subsidized immunizations. This retrospective cohort study assessed the relationship of gender, race, location of birth, late start to immunization (after 92 days of life), and distance to provider with completion of an immunization series. Distance to provider was categorized as small (0.00-3.00 mi), medium (3.01-6.00mi) and large (6.00+ mi) and was the primary variable under investigation. The researchers hypothesized that a larger distance to provider was associated with a decrease in series completion. Data pertaining to the aforementioned variables was obtained from the Jefferson electronic medical record (EMR). Descriptive statistics were used to summarize the study population characteristics and logistic regression was used to assess the relationship between distance to provider and series completion, while controlling for other variables. A descriptive map was developed to illustrate percent series incompletion by distance. (cont’d)

The study population of 301 infants was equally split by gender (49.8% male vs 50.2% female), (predominantly African American (83.4%), born at Jefferson (63.8%), lived within 6 miles to their provider (74.8%) and had a late start to immunization (58.5%). A total of 47.5% of infants did not complete their immunization series in 24 months. Univariate logistic regression indicated that race other than black, being born outside of Jefferson and having a late start were significantly (p<.05) associated with incomplete immunization. Multivariate logistic regression indicated that distance did not have a significant impact on series completion, nor did other covariates in the model. The map shows incomplete series across distance categories (50.5%, 49.2% and 40.8% for small, medium, and large). This study adds to the literature on distance, location of birth and late start with immunization series completion and aids in identifying possible intervention targets.

Presentation: 25 minutes