Assessing the burden of undeliverable immunization reminder and recall notifications.

PURPOSE: To assess the completeness and accuracy of parent contact information for the delivery of mailed reminder/recall notices using a statewide immunization information system (IIS). METHODS: The Michigan Care Improvement Registry (MCIR) was used to generate reminder and recall notifications for children ages 6 months-19 years in Michigan (2008-2009). Mailed notifications were classified as being undeliverable if they were returned to the local health department (LHD) by the US Postal Service. RESULTS: 20-377 notifications were mailed and 5182 (26%) were undeliverable. Undeliverable notification increased with age (reference- 6-18 months): 19-35 months (OR=1.27)- 36-71 months (OR=3.03) and adolescents 11-19 years (OR=4.94). Children enrolled in Medicaid (OR=0.76) were less likely to have an undeliverable notification compared to their non-enrolled counterparts- but children who had previously received some (OR=1.07) or all vaccinations (OR=2.43) at an LHD were more likely to have an undeliverable notifica