Heard immunity: effective messaging for a future COVID-19 vaccine

Last registered on July 10, 2020

Pre-Trial

Trial Information

General Information

Title
Heard immunity: effective messaging for a future COVID-19 vaccine
RCT ID
AEARCTR-0006133
Initial registration date
July 09, 2020
Last updated
July 10, 2020, 10:01 AM EDT

Locations

Region

Primary Investigator

Affiliation
Sol Price School of Public Policy/USC

Other Primary Investigator(s)

Additional Trial Information

Status
In development
Start date
2020-07-13
End date
2020-09-14
Secondary IDs
Abstract
This study uses a survey experiment to determine the most effective messaging to persuade people to take up a future vaccine for COVID-19. Ending the pandemic necessitates enough vaccination to achieve herd immunity, but survey evidence suggest up to 50% of people are hesitant to vaccinate. The survey divides respondents into one control and four treatment groups. Each treatment group is exposed to a message emphasizing either the benefits of vaccination or the risks of avoiding vaccination, to the respondent personally or to society in general. The survey is administered by USC's Understanding America Survey to a nationally representative panel. The outcome measure of interest is differences in self-reported intention to vaccinate for the four treatment arms relative to control, using a means-comparison test with inference adjusted for the testing of four hypotheses.
External Link(s)

Registration Citation

Citation
Duquette, Nicolas. 2020. "Heard immunity: effective messaging for a future COVID-19 vaccine." AEA RCT Registry. July 10. https://doi.org/10.1257/rct.6133-1.0
Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2020-07-13
Intervention End Date
2020-09-14

Primary Outcomes

Primary Outcomes (end points)
Self-reported intention to vaccinate against COVID-19 in the future
Primary Outcomes (explanation)
Respondents are asked whether they want the coronavirus vaccine when it becomes available. I code "Yes" as 1 and "No" or "I don't know / Not sure" as 0.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Survey experiment.
Experimental Design Details
Randomization Method
By computer
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
n/a
Sample size: planned number of observations
2200
Sample size (or number of clusters) by treatment arms
440
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
effect size 30% standard deviation is rejected 80% of the time.
IRB

Institutional Review Boards (IRBs)

IRB Name
University of Southern California Institutional Review Board
IRB Approval Date
2020-06-10
IRB Approval Number
UP-14-00148-AM080
Analysis Plan

There are documents in this trial unavailable to the public. Use the button below to request access to this information.

Request Information

Post-Trial

Post Trial Information

Study Withdrawal

There are documents in this trial unavailable to the public. Use the button below to request access to this information.

Request Information

Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials