The use of an immunization information system to establish baseline childhood immunization rates and measure contract objectives.

Measuring progress toward national immunization objectives at the local level, although difficult, is becoming more feasible owing to statewide immunization information systems. This article describes how a state immunization program expanded the scope of immunization service contracts with local health departments (LHDs) to address the immunization rates among children living within their jurisdictions using the Wisconsin Immunization Registry (WIR) to measure achievement of population-based objectives. By contract year (CY) 2008, 99 percent of Wisconsin LHDs selected population-based contract objectives. In late 2008, the Wisconsin Immunization Program assessed all children at 24 months of age for completeness of the 4:3:1:3:3:1 (diphtheria, tetanus, pertussis/poliovirus/measles-containing vaccine/Haemophilus influenzae type b/hepatitis B/varicella) series by county for each of four CYs, using the WIR. From CY 2005 to CY 2008, LHDs in 61 (86%) of the 71 counties demonstrated increased series completeness rates for the series, and the overall statewide series completeness increased from 58 percent to 64 percent. However, the increases we observed cannot be attributed solely to LHDs' acceptance of population-based objectives because controlling for other factors known to influence immunization coverage levels was outside the scope of this case study. We found the WIR to be a powerful tool that can measure immunization coverage among local populations independent of the immunization provider, assess improvement toward contract objectives, and target resources toward pockets of need.