Centralized Immunization Recall in a Large Urban Area

Background: Immunization reminder/recall has been shown to improve vaccination coverage rates.  It is unclear the extent to which immunization reminder/recall may be successful using a centralized approach, targeting all children (i.e., those immunized in public AND private settings) from a local health department.  Moreover, little is known about whether the content and format of recall notices influences the success of recall efforts.

Objectives: To assess the effectiveness of immunization recall for overdue vaccinations in a large urban area with historically low vaccination rates that 1) uses a centralized approach based on high-functioning statewide immunization information system; and 2) incorporates the format and content preferences of parents.

Methods: Parent focus groups were conducted in Detroit and surrounding Wayne County, Michigan, to identify preferences regarding recall notice content and format.  Responses were synthesized into an enhanced recall notice. Recall notifications were generated for 19-month-old children using the Michigan Care Improvement Registry (MCIR) in four cycles (June 2008, September 2008, January 2009, June 2009).  Eligible children were randomized into three groups (standard recall, enhanced recall, no recall) in each recall cycle; notices were delivered by US Postal Service mail.  

Results: Among 3,233 eligible children, 1,119 were mailed standard recall notices, 1,164 were mailed enhanced recall notices. and 950 had no recall.  Eight weeks following notification, the proportion receiving ≥1 vaccination dose was marginally higher among both recall groups (26%, 25%) versus those not notified (20%).  At age 2 years, 48% of the standard recall group had received at least 1 vaccination, compared to 47% among the enhanced notification group and 42% among those not notified.

Conclusions: Recall reminders were associated with a modest increase in vaccination among 19 month children in a large urban center.  However, incorporating parent preferences into the format of the recall notice did not influence recall success.