Objective: To estimate whether text messages sent to ambulatory pregnant women could improve influenza vaccine uptake.
Methods: Obstetric patients at less than 28 weeks of gestation were enrolled in a randomized controlled trial from an academic center's outpatient clinic during two consecutive influenza seasons (2010-2011 and 2011-2012). Potential participants were excluded if they had already received that season's influenza vaccine. Participants were randomized to receive 12 weekly text messages encouraging general pregnancy health (General) or general pregnancy health plus influenza vaccination (Flu). Study participants completed preintervention and postintervention surveys about preventive health beliefs. Influenza vaccine receipt was assessed using prenatal record review. The study was powered to detect a 55% increase in the vaccination rate in the intervention group.
Results: Two hundred sixteen women were enrolled, 204 of whom were available for intention-to-treat analysis (n=100 General, n=104 Flu). Participants were primarily African American (66%) with low educational attainment (90% equivalent to or less than high school education) and predominantly with either public or no insurance (88%). The overall influenza vaccination rate among participants was 32% with no difference between participants in the General (31% [n=31]) compared with Flu (33% [n=34]) groups (difference 1.7%, 95% confidence interval -11.1 to 14.5%).
Conclusion: Text messaging prompts were not effective at increasing influenza vaccination rates among a low-income, urban, ambulatory obstetric population. Ongoing efforts are needed to improve vaccine uptake among pregnant women unsure about or unwilling to receive influenza vaccination.
Clinical trial registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT01248520.
Level of evidence: : I.