NCT05182554

Brief Summary

This study will distribute videos of health professionals encouraging Covid-19 vaccination to a large sample of Facebook users, and will test the most effective ways to maximize diffusion of this vaccine-related content to increase vaccination rates. The study sample will be U.S. states where vaccination rates remained low in fall 2021. The experimental design is an RCT with 4 groups, randomized at the county level: 1) a control group which receives no intervention, 2) a treatment group in which Facebook users receive ads which include videos of health professionals telling them to get vaccinated, 3) a treatment group in which Facebook users receive ads which include videos of health professionals encouraging them to help their friends to get vaccinated, and 4) a treatment group in which Facebook users receive ads which include videos of health professionals encouraging them to get their most influential friends to help their friends get vaccinated. In treatments 3 and 4, participants will have the option to sign up to be a "vaccine ambassador," in which case they will get notifications when the study team posts new vaccine-related content, and will receive reminders about encouraging their friends to be vaccinated. The vaccine ambassadors will also be entered into a lottery to win prizes. The study team is building a website to host the videos of health professionals which answer common questions about Covid-19 vaccination. The investigators will measure engagement with the vaccine-related content as well as assess effects on vaccination rates at the county level.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
6

participants targeted

Target at below P25 for not_applicable

Timeline
Completed

Started Dec 2021

Shorter than P25 for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

October 21, 2021

Completed
2 months until next milestone

Study Start

First participant enrolled

December 22, 2021

Completed
19 days until next milestone

First Posted

Study publicly available on registry

January 10, 2022

Completed
17 days until next milestone

Primary Completion

Last participant's last visit for primary outcome

January 27, 2022

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

January 27, 2022

Completed
1.6 years until next milestone

Results Posted

Study results publicly available

August 25, 2023

Completed
Last Updated

August 25, 2023

Status Verified

August 1, 2023

Enrollment Period

1 month

First QC Date

October 21, 2021

Results QC Date

March 17, 2023

Last Update Submit

August 23, 2023

Conditions

Keywords

Covid-19 VaccineSocial Media

Outcome Measures

Primary Outcomes (1)

  • Changes in County-Level Covid-19 Vaccination Measured by Inverse Hyperbolic Sine

    County-level Covid-19 vaccination rates were analysed using publicly available data. The number of new vaccinations in each county was transformed using the inverse hyperbolic sine because the underlying vaccination count data were right-skewed and included zeros. Larger numbers are considered better in the context of the study (more people vaccinated).

    During intervention (6 weeks) and after intervention (3 weeks)

Study Arms (4)

Control

NO INTERVENTION

No intervention in this arm; the study team will examine publicly available county- and zip code-level outcomes in this group.

Treatment 1: Direct

EXPERIMENTAL

Facebook users in the area receive ads which include videos of health professionals telling them to get vaccinated. The health professionals answer common questions about Covid-19 vaccines (e.g. are they safe / are they free).

Behavioral: Doctor Videos

Treatment 2: Friends

EXPERIMENTAL

Facebook users in the area receive ads which include videos of health professionals encouraging them to help their friends to get vaccinated. There is also a link in the ad to a website build by the study team. This website hosts videos which answer common questions about vaccination (the same videos which are directly served to Facebook users in Treatment 1).

Behavioral: Doctor VideosBehavioral: Sharing VideosBehavioral: Vaccine AmbassadorBehavioral: Video framingBehavioral: Video order

Treatment 3: Gossips

EXPERIMENTAL

Facebook users in the area receive ads which include videos of health professionals encouraging them to nominate their most influential friends to help their friends get vaccinated. The difference from Treatment 2 is that the health professionals call on Facebook users to get their most influential friends to do the convincing about the vaccine. There is also a link in the ad to a website built by the study team. This website hosts videos which answer common questions about vaccination (the same videos that are directly served to Facebook users in Treatment 1).

Behavioral: Doctor VideosBehavioral: Sharing Videos (Influencers)Behavioral: Vaccine AmbassadorBehavioral: Video framingBehavioral: Video order

Interventions

Doctor VideosBEHAVIORAL

Receive ads on Facebook or through our website with videos in which health professionals tell people to get the Covid-19 vaccine. The health professionals answer common questions about the Covid-19 vaccine, such as how mRNA vaccines work, and what types of side effects to expect.

Treatment 1: DirectTreatment 2: FriendsTreatment 3: Gossips
Sharing VideosBEHAVIORAL

Receive ads on Facebook with videos in which health professionals tell people to encourage their unvaccinated friends to get the Covid-19 vaccine.

Treatment 2: Friends

Receive ads on Facebook with videos in which health professionals tell people to get their most influential friends to encourage their unvaccinated friends to get the Covid-19 vaccine.

Treatment 3: Gossips

Adults in participating geographic areas can sign up to be a "vaccine ambassador" on a website that the study team has built. The study team will send updates to vaccine ambassadors when new content has been posted to the website (e.g. a new video) and/or to remind the vaccine ambassadors to encourage their friends to get vaccinated. The study team will incentivize vaccine ambassadors by entering participating ambassadors into a lottery for a prize.

Treatment 2: FriendsTreatment 3: Gossips
Video framingBEHAVIORAL

The same videos will be displayed using two different frames: a "myth" frame and a "fact" frame. Visitors to the vaccine content website will randomly receive one framing of each video.

Treatment 2: FriendsTreatment 3: Gossips
Video orderBEHAVIORAL

The order in which videos appear on the vaccine content website will be randomized.

Treatment 2: FriendsTreatment 3: Gossips

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Facebook user
  • Over 18 years old
  • In a geographic area targeted by the study

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Massachusetts Institute of Technology

Cambridge, Massachusetts, 02139, United States

Location

MeSH Terms

Conditions

Vaccination RefusalCOVID-19

Condition Hierarchy (Ancestors)

Treatment RefusalTreatment Adherence and ComplianceHealth BehaviorBehaviorPneumonia, ViralPneumoniaRespiratory Tract InfectionsInfectionsVirus DiseasesCoronavirus InfectionsCoronaviridae InfectionsNidovirales InfectionsRNA Virus InfectionsLung DiseasesRespiratory Tract Diseases

Results Point of Contact

Title
LISA HO
Organization
MIT

Study Officials

  • Esther Duflo, PhD

    Massachusetts Institute of Technology

    PRINCIPAL INVESTIGATOR
  • Ben Olken, PhD

    Massachusetts Institute of Technology

    PRINCIPAL INVESTIGATOR
  • Abhijit Banerjee, PhD

    Massachusetts Institute of Technology

    PRINCIPAL INVESTIGATOR
  • Marcella Alsan, MD, PhD

    Harvard Kennedy School

    PRINCIPAL INVESTIGATOR
  • Arun Chandrasekhar, PhD

    Stanford University

    PRINCIPAL INVESTIGATOR
  • Emily Breza, PhD

    Harvard University

    PRINCIPAL INVESTIGATOR
  • Paul Goldsmith-Pinkham, PhD

    Yale University

    PRINCIPAL INVESTIGATOR
  • Emily Hoppe, PhD Student

    Johns Hopkins School of Nursing

    PRINCIPAL INVESTIGATOR
  • Pierre-Luc Vautrey, PhD Student

    Massachusetts Institute of Technology

    PRINCIPAL INVESTIGATOR
  • Lisa Ho, PhD Student

    Massachusetts Institute of Technology

    PRINCIPAL INVESTIGATOR
  • Lucy Ogbu-Nwobodo, MD

    MGH/McLean Harvard Psychiatry Program

    PRINCIPAL INVESTIGATOR
  • Erica Warner, ScD, MPH

    Harvard Medical School & Massachusetts General Hospital

    PRINCIPAL INVESTIGATOR
  • Carlos Torres, MD

    Massachusetts General Hospital

    PRINCIPAL INVESTIGATOR
  • Fatima Stanford, MD, MPH, MPA

    Harvard Medical School & Massachusetts General Hospital

    PRINCIPAL INVESTIGATOR
  • Sarah Eichmeyer, PhD

    Ludwig-Maximilians - University of Munich

    PRINCIPAL INVESTIGATOR

Publication Agreements

PI is Sponsor Employee
No
Restrictive Agreement
No

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
TREATMENT
Intervention Model
PARALLEL
Model Details: There are four arms in the study which geographic areas are assigned to in parallel. The geographic areas in the three treatment arms will receive a Facebook ad campaign over the same time period to one another.
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

October 21, 2021

First Posted

January 10, 2022

Study Start

December 22, 2021

Primary Completion

January 27, 2022

Study Completion

January 27, 2022

Last Updated

August 25, 2023

Results First Posted

August 25, 2023

Record last verified: 2023-08

Data Sharing

IPD Sharing
Will not share

The investigators do not plan to share any individual participant data. The only individual participant data that the study will collect will be contact information through the "vaccine ambassador" program. "Vaccine ambassadors" are adults living in geographic areas assigned to Treatment 2 or Treatment 3 who have signed up on the study website to receive updates and reminders about vaccination-related content. However, the study team does not plan on collecting any information about the behavior of vaccine ambassadors, and so do not plan to share any of their data (which will just consisting of contact information) with other researchers.

Locations