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Effect of Text Message Reminders and Vaccine Reservations on Adherence to a Health System COVID-19 Vaccination PolicyA Randomized Clinical Trial

Educational Objective
To identify the key insights or developments described in this article
Key Points

Question  Can a behavioral nudge delivered through text messages with a reserved date for vaccination over a 2-week period accelerate employee adherence with a health system COVID-19 vaccination policy?

Findings  In this randomized clinical trial of 2000 participants, the behavioral nudge delivered through text messages significantly increased adherence to the health system COVID-19 vaccination policy by 4.9 percentage points compared with the control group during the 2-week intervention period. At the 4-week time point near the vaccination policy deadline, there was no longer a significant difference in the overall adherence rate between groups.

Meaning  This randomized clinical trial found that a behavioral nudge delivered by text message with a reserved date for vaccination accelerated adherence to a health system COVID-19 vaccination policy; however, other approaches may be needed to change overall adherence rates by the time of the policy deadline.


Importance  Many organizations implemented COVID-19 vaccination requirements during the pandemic, but the best way to increase adherence to these policies is unknown.

Objective  To evaluate if behavioral nudges delivered through text messages could accelerate adherence to a health system’s COVID-19 vaccination policy.

Design, Setting, and Participants  This randomized clinical trial was conducted within Ascension health system from October 11 to November 8, 2021. Participants included health system employees in the Midwest or South US who were not adherent with the vaccination policy 1 month before its deadline. Data were analyzed from November 17, 2021, to February 25, 2022.

Interventions  Participants were randomly assigned to control or to receive a text message intervention that stated a vaccine had been reserved for the participant, with a scheduled date for vaccination within a 2-week period. Participants could reschedule to a different date within the period or upload a copy of their vaccination card. Follow-up text message reminders were sent the day before and the day of the appointment.

Main Outcomes and Measures  The primary outcome was adherence to the health system’s vaccination policy during the 2-week intervention. Secondary outcomes included time to vaccination during a 4-week follow-up period.

Results  The sample included 2000 participants (mean [SD] age, 36.4 [12.3] years; 1724 [86.2%] women), with 1000 participants randomized to the control group and 1000 participants randomized to the intervention group. Overall, there were 164 Hispanic participants (8.2%), 46 non-Hispanic Asian participants (2.3%), 202 non-Hispanic Black participants (10.1%), and 1418 non-Hispanic White participants (70.9%). By the end of the 2-week intervention, 363 participants in the text message nudge group (36.3%) and 318 participants in the control group (31.8%) were adherent with the vaccination policy, representing a significant increase of 4.9 (95% CI, 0.8 to 9.1) percentage points in adjusted analyses comparing the nudge group with the control group (P = .02). Among participants who became adherent by the end of the 4-week follow-up period, the text message nudge significantly reduced time to adherence by a mean of 2.4 (95% CI, 2.1 to 4.7) days (P < .001) and a median of 5.0 (95% CI, 2.5 to 7.7) days (P < .001) compared with the control group. At 4 weeks, overall vaccination adherence was no longer different between groups (control: 477 participants [47.7%]; intervention: 472 participants [47.2%]).

Conclusions and Relevance  This randomized clinical trial found that a behavioral nudge delivered through text messages accelerated adherence to a health system’s COVID-19 vaccination policy but did change overall adherence by the time of the policy deadline.

Trial Registration  ClinicalTrials.gov Identifier: NCT05037201

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Article Information

Accepted for Publication: May 29, 2022.

Published: July 20, 2022. doi:10.1001/jamanetworkopen.2022.22116

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2022 Patel MS et al. JAMA Network Open.

Corresponding Author: Mitesh S. Patel, MD, MBA, Ascension, 4600 Edmundson Rd, St Louis, MO 63134 (mitesh.patel3@ascension.org).

Author Contributions: Dr. Patel had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Patel, Fogel, Habash, Brinson, Price, Yehia.

Acquisition, analysis, or interpretation of data: Patel, Winegar, Horseman, Ottenbacher, Habash, Dukes, Brinson, Price, Masoudi, Cacchione.

Drafting of the manuscript: Patel, Dukes, Brinson.

Critical revision of the manuscript for important intellectual content: Fogel, Winegar, Horseman, Ottenbacher, Habash, Dukes, Brinson, Price, Masoudi, Cacchione, Yehia.

Statistical analysis: Winegar, Horseman, Dukes, Price.

Obtained funding: Patel.

Administrative, technical, or material support: Winegar, Ottenbacher, Dukes, Brinson, Price, Cacchione, Yehia.

Supervision: Patel, Fogel, Winegar, Price.

Conflict of Interest Disclosures: Dr Patel reported receiving personal fees from Catalyst Health, Humana, and GlaxoSmithKline outside the submitted work. No other disclosures were reported.

Funding/Support: This study was funded internally by Ascension.

Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Data Sharing Statement: See Supplement 3.

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