BACKGROUND:
Oregon's Registry (Immunization ALERT) participates as a CDC Registry Sentinel Project since 2000. CDC defines a Registry Sentinel site as a one that contains a population of children with complete vaccination histories so that changes in coverage can be rapidly detected and monitored. Oregon's Sentinel population includes 38K children ages 0-6 years living in a contiguous geographic region west of Portland, Oregon's largest metropolitan area.

OBJECTIVE:
Use data from Oregon's Sentinel population to detect changes in immunization coverage over time, determine the impact of shortages, and evaluate the implementation of new recommendations.

METHOD:
Extracted data from ALERT for the population of children ages 0-6 years with last known address in the defined Sentinel geographic area. Identified monthly age cohorts as of the assessment date, and calculated single antigen and combined antigen rates for each cohort.

RESULT:
Assessed 34,616 children from ages 7 to 71 months old using ALERT data and produced the following results for the Sentinel Region population: Hep A immunization rates are consistently at 40%-50% between 27 and 71 months of age; Flu immunization rates peak at 25% for children between 12 and 27 months of age; 95% of all children have at least one PCV7 dose at 7 months of age; rates for the 4th dose of PCV7 are lowest during the period of vaccine shortage; MMR and VAR immunization rates are comparable for all children between ages 12 and 50 months of age.

CONCLUSION:
The registry sentinel data provides a rich source of information to monitor changes in immunization rates for young children, and to isolate changes attributable to improved vaccine uptake or to external events such as vaccine shortages.

LEARNING OBJECTIVES:
Describe how to use registry data for a specific population to track immunization rates over time.