A gamified approach to combat vaccine hesitancy

Last registered on December 06, 2023


Trial Information

General Information

A gamified approach to combat vaccine hesitancy
Initial registration date
December 05, 2023

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
December 06, 2023, 9:05 AM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.


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

Request Information

Primary Investigator

City, University of London

Other Primary Investigator(s)

PI Affiliation
City, University of London
PI Affiliation
Office for Health Economics
PI Affiliation
City, University of London

Additional Trial Information

In development
Start date
End date
Secondary IDs
SRG22\221123, ETH2223-2051
Prior work
This trial does not extend or rely on any prior RCTs.
The COVID-19 pandemic made vaccine hesitancy the focus of global attention and concern and was listed as a global health threat by the WHO in 2019. In theory, a perfectly coordinated collective action can result in disease eradication. In reality, the "wait-and-see" strategy and self-centric behaviour precluded the elimination of COVID-19. Moreover, the "infodemic" around COVID-19 resulted in a WHO's call for increased resilience against misinformation. In this project, we propose developing and testing the impact of three online games designed around vaccine literacy, empathy, and misinformation training to increase vaccination intentions. We intend to bring evidence from countries with overall high/low vaccination rates (the UK and Slovakia to start with) to address concerns about the replicability of experiments and utilise across-country heterogeneities. Gamified interventions have become popular recently, but the evidence of their effectiveness remains scarce. Therefore, our results will also contribute to the discussion about digital media's role in strengthening vaccine confidence. Later, the games can be translated into multiple languages, finetuned to fit other vaccine-preventable diseases or more specific audiences, or used in nationwide interventions. We believe our research has substantial policy implications.
External Link(s)

Registration Citation

Celik Katreniak, Dagmara et al. 2023. "A gamified approach to combat vaccine hesitancy." AEA RCT Registry. December 06. https://doi.org/10.1257/rct.12655-1.0
Sponsors & Partners

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

Request Information
Experimental Details


We propose two online games - misinformation and empathy games - to investigate whether active learning of (a) misinformation strategies, (b) affective empathy, or (c) improving vaccine literacy, can influence vaccine-hesitant intentions in general. The fourth game will be a placebo game with none of these components. We therefore aim to shed light on potential mechanisms underpinning vaccine hesitancy. Moreover,
certain information/news will be shared throughout the games with the participants, and we plan to alter the identity of the sender (e.g., a governmental body, a scientist, or a celebrity). This way, we will be able to understand whether the success of the intervention depends on the sender’s position in society.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Primary outcomes are: vaccination intentions, misinformation detection, subjective measure of ability to detect misinformation, empathy, propensity to free ride
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
We plan to proceed with heterogeneity analysis based on gender, age, vaccination status, opinion on climate change, subjects' social preferences and norms, demographics and political views.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We will cooperate with an external survey company using their online pool of people. The respondents will be directed to play our (treatment/placebo) game and then redirected back to the survey company. Randomization, after stratification on respondents' vaccination/climate change views, will be embedded in the design of the game. Decisions are incentivized and each participant will be included in a lottery in which the result of the game will determine the number of entries he/she has in the lottery (i.e., the higher the game result, the higher the chance to win the lottery).
Experimental Design Details
Not available
Randomization Method
Randomization will be done by a computer, following a stratification based on vaccination/climate change opinion.
Randomization Unit
We will randomize on an individual level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
We don't have clusters.
Sample size: planned number of observations
In total, in the initial stage, we should have the budget for cca 1100 participants for the experiment in the UK, and 1200 participants for the experiment in Slovakia.
Sample size (or number of clusters) by treatment arms
We plan to assign 30% of the sample to the control group and 70% to the treatment group (for each game in each country).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
With a current sample availability, we should be able to detect 0.08 change in outcomes measured as proportions (e.g., vaccine intentions) and cca change in means by 0.1-0.2 standard deviation for other measures.
Supporting Documents and Materials

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

Request Information

Institutional Review Boards (IRBs)

IRB Name
Ethical Committee of City, University of London
IRB Approval Date
IRB Approval Number