Age-specific strategies for immunization reminders and recalls: a registry-based randomized trial.
BACKGROUND: Although previous studies have found reminder/recall to be effective in increasing immunization rates- little guidance exists regarding the specific ages at which it is optimal to send reminder/recall notices. PURPOSE: To assess the relative effectiveness of centralized reminder/recall strategies targeting age-specific vaccination milestones among children in urban areas during June 2008-June 2009. METHODS: Three reminder/recall strategies used capabilities of the Michigan Care Improvement Registry (MCIR)- a statewide immunization information system: a 7-month recall strategy- a 12-month reminder strategy- and a 19-month recall strategy. Eligible children were randomized to notification (intervention) or no notification groups (control). Primary study outcomes included MCIR-recorded immunization activity (administration of