Reminder/Recall In High Risk Areas Using Immunization Information Systems

Background: Immunization rates vary throughout Minnesota. We identified 12 ZIP codes with historic and currently low immunization rates relative to other areas of Minnesota. In order to increase immunization rates in these ZIP codes, reminder/recall activities targeted children ages 24-35 months who are not up-to-date (UTD) on their 4:3:1:3:3:1:4 series.

Setting: Minnesota Department of Health, providers in and around the 12 selected ZIP Codes.

Population: 24-35 month olds living in the selected ZIP codes.

Project Description: ZIP codes were chosen based on current 4:3:1:3:3:1:4 UTD rates, retrospective studies of 4:3:1 UTD rates from 1993, 1997 and 2002, and family poverty rates.  Minnesota Immunization Information Connection (MIIC), the state’s immunization information system, was used to identify a cohort of not UTD children residing in the selected ZIP codes, ages 24-35 months as of November 1^st, 2010. Parents of not UTD children were sent letters in February 2011.  Follow up letters were sent quarterly to parents of kids who remained not UTD.  Letters were re-sent after mail was returned using alternative addresses in MIIC (when available) and/or updated addresses from the Ramsey County WIC database.  A random sample of individuals with a phone number listed in MIIC were selected to receive a call regarding their not UTD children.  12 control ZIP codes were also selected and matched on population, urban or rural setting and poverty rate. 

Results/Lessons Learned: The overall UTD percentage increased by over 16.4% in the targeted ZIP codes compared to a 4.2% increase in the control ZIP codes.  6,152 immunizations were added to MIIC records of not UTD cohort members during the project.  1,490 (24.2%) were newly administered shots; 4,662 (75.8%) were administered prior to the onset of the project and represent historical data entry.  These reminder/recall efforts had a possible impact on immunization rates in these 12 ZIP codes.