Immunization Rates among Oregon Medicaid and WIC Participants

Background:
Through an Oregon Immunization and WIC partnership, Immunization Information System-based immunization forecasting is available at all WIC visits. OIP also partners with the Division of Medical Assistance Programs (DMAP) to determine immunization rates for children on Medicaid.

Objectives:
To explore associations between Medicaid and WIC enrollment and up-to-date rates.

Methods:
For two year olds born in Oregon in 2005, ALERT, WIC and DMAP participation were assessed as of 1/1/2008. Medicaid status was assessed for a minimum of one year enrollment by age two. Population-based immunization rates (UTD) for the 4:3:1:3:3:1 series were determined for WIC and DMAP separately and together.

Results:
For a 4:3:1:3:3:1 series with recommended spacing, children enrolled in Medicaid had a 2007 UTD rate of 77.9%; WIC enrolled children had a 77.6% UTD rate; and children enrolled in both Medicaid and WIC had a UTD rate of 81.4%. In comparison, the statewide rate for all children was 74.1%. In contrast to overall rates, children enrolled exclusively in Medicaid, not WIC, had a 62.0% UTD rate and children enrolled exclusively in WIC, not Medicaid, had a 73.5% UTD rate.

Conclusions:
In Oregon, a combination of WIC and Medicaid enrollment significantly increased the likelihood that children will receive all recommended vaccinations. Findings reinforce the value of Oregon partnerships between Immunizations, WIC and DMAP.