Behaviorally Informed Text Message Nudges to Schedule COVID-19 Vaccinations: A Randomized Controlled Trial.

Background: Vaccine hesitancy, especially related to COVID-19 vaccinations among Veterans, may limit uptake. Behaviorally informed text-based messages have the potential to improve uptake of COVID-19 vaccinations.

Objective: To evaluate the impact of two different behaviorally informed text message nudges on COVID-19 vaccine scheduling and completion, compared to standard control message.

Design: Prospective, three-arm patient-level randomized quality improvement trial.

Participants: Between March and May 2021, 20,523 Veterans were eligible for the initial series of COVID-19 vaccination, enrolled at two large Veterans Health Administration sites.

Intervention: Arm 1 (Control): standard scheduling message; Arm 2 (Social Good): standard message plus behaviorally informed text message "When you get a vaccine now, you help protect yourself, your family, and your community"; and Arm 3 (Scarcity): standard plus behaviorally informed text message "Only a limited number of vaccine appointments are available."

Main measures: Outcomes were vaccine scheduling and/or completion rate within 7 days of receipt of text message (primary), and within 14 days and 30 days after receipt of text message (secondary).

Key results: Veterans had an overall rate of 19% of scheduling or receiving a vaccination in 7 days. In our adjusted intention-to-treat analysis, we found no difference between intervention social good or scarcity (aOR 0.98, 95% CI, 0.88-1.09, for both arms) compared to standard scheduling message. We found no statistical differences in our secondary outcomes.

Conclusions: During the initial phases of vaccine roll-out, two behaviorally informed text messages did not increase COVID-19 vaccination rates among Veterans compared to a standard scheduling message.