BACKGROUND:
2002 NIS ranked Colorado last among all states for the 4:3:1:3 series. Characterizing underimmunized children in Colorado is difficult as the NIS sample is small and Colorado lacks population-based data regarding childhood immunizations. The Colorado Immunization program attempted to identify PONs, using maternal risk factors for underimmunization available from birth certificates.

OBJECTIVE:
Identify immunization PONs in Colorado using maternal risk factors.

METHOD:
State birth records for the years 2000 to 2002 were geocoded to the block group level. Four maternal characteristics, identified from the literature were included: number of siblings greater than or equal to 2, mother°¦s age less than 21, mother°¦s education level less than High School and mother unmarried. A child was considered at risk if their mother had at least two of these characteristics. Colorado block groups with a high percentage of at risk children (ƒ®50%) and high concentrations of births (total number of births >1 standard deviation above the mean) were classified as immunization PONs.

RESULT:
Of the 184,041 births over the 3 year study period, 45,240 were classified as being at risk for underimmunization (25%). This study identified 103 block groups as immunization PONs. Although these PONs represent a small percentage of Colorado°¦s block groups, just 3%, they account for over 18% of all at risk births. Regional registry data will be used to investigate the proportion of underimmunized children in these block groups.

CONCLUSION:
Identifying PONS is critical in targeting state program activities. States without population based data sources can utilize indirect measures of risk to identify PONS. The PONs found in this study will be verified with available direct measures of immunization status to assess whether this maternal risk model identifies underimmunized in Colorado.

LEARNING OBJECTIVES:
This study outlines one method that can be used to identify statewide immunization PONs.