NCT04706403.

Study name	If we build it, will they come? A pilot study to develop and test messages to maximize uptake of coronavirus vaccine when available
Starting date	12 January 2021
Contact information	NR
Methods	Study design: randomised controlled trial Type of publication: trial registration Setting: online Country: USA Language: English
Intervention	Participants who express hesitation about getting vaccinated for COVID‐19 will be randomised to receive one of five different versions of messages from a healthcare provider (experimental groups) or a control message (control group). The messages that participants in each experimental group receive will vary slightly and systematically. Specific content and wording of these messages will be developed to address and mitigate concerns of those at risk for not being vaccinated.
Population	Inclusion criteria: adult (age 18 and over) who are members of an online panel (Prolific); able to complete an on‐line survey in English.
Outcomes	Primary outcome Intent to be vaccinated against COVID‐19. [Time frame: through survey completion, an average of 12 minutes Secondary outcome Predictors of intent to be vaccinated against COVID‐19. [Time frame: through survey completion, an average of 12 minutes]
Estimated completion date and number of participants	1 February 2021 with 1706 participants
Notes	Sponsor: University of Massachusetts, Worcester COI: NR