NCT04800965.

Study name	Text‐based interventions to promote COVID‐19 vaccinations
Starting date	31 January 2021
Contact information	NR
Methods	Study design: randomised controlled trial Type of publication: trial registration Setting: UCLA health Country: USA Language: English
Intervention	Holdout arm: patients will not receive text messages about COVID‐vaccine. Simple Text sub‐arm: participants will not receive any additional information. Simple Text+Video sub‐arm: together with the appointment link, participants will also receive a link to a 2‐minute video in the text message.  Enhanced Text sub‐arm: in addition to the appointment link, the text message will use enhanced language aimed at reducing psychological barriers that prevent patients from scheduling their appointment. Enhanced Text+Video sub‐arm: in addition to the appointment link, the text message will encourage patients to watch a 2‐minute video (the same as in the Simple Text+Video sub‐arm) and use enhanced language aimed at reducing patients' psychological barriers of following through on scheduling an appointment.
Population	Population: students at UCLA Inclusion criteria: participants have a mobile phone number or SMS capable phone number in UCLA Health's database; are eligible for receiving the COVID‐19 vaccine at UCLA Health; have not already scheduled an appointment the day before the scheduled time of text message; are at or above 18 years old.
Outcomes	Primary outcome First COVID‐19 vaccine appointment scheduled at UCLA Health [Time frame: 6 days] Secondary outcomes First COVID‐19 vaccine obtained at UCLA Health [Time frame: 1 month from text message] Time of obtaining the first COVID‐19 vaccine at UCLA Health [Time frame: 1 month from text message] First COVID‐19vVaccine obtained at UCLA Health or any organisation reporting to CAIR [Time frame: 2 months from text message] Time of obtaining the first COVID‐19 at UCLA Health or another location reporting to CAIR [Time frame: 2 months from text message]
Estimated completion date and number of participants	1 January 2022 with 400,000 participants
Notes	Sponsors: University of California, Los Angeles and Carnegie Mellon University COI: NR