Impacting delayed pediatric influenza vaccination: a randomized controlled trial of text message reminders.

BACKGROUND: Influenza vaccination coverage is low- especially among low-income populations. Most doses are generally administered early in the influenza season- yet sustained vaccination efforts are crucial for achieving optimal coverage. The impact of text message influenza vaccination reminders was recently demonstrated in a low-income population. Little is known about their effect on children with delayed influenza vaccination or the most effective message type. PURPOSE: To determine the impact of educational plus interactive text message reminders on influenza vaccination of urban low-income children unvaccinated by late fall. DESIGN: Randomized controlled trial. SETTING/PARTICIPANTS: Parents of 5-462 children aged 6 months-17 years from four academically affiliated pediatric clinics who were unvaccinated by mid-November 2011. INTERVENTION: Eligible parents were stratified by their child's age and pediatric clinic site and randomized using a 1:1:1 allocation to educational plus interactive text message re