Building Cognitive Resilience to Vaccine Misinformation Using AI in Europe

April 27, 2026 updated by: London School of Hygiene and Tropical Medicine

Building Cognitive Resilience to Vaccine Misinformation Using Conversational AI: Evidence From a Multi-Country European Randomised Trial

This multi-country trial evaluates an AI chatbot designed to counter cognitive biases and inoculate parents against vaccine misinformation, embedded within a large survey across five European countries (n=5,000). Scaled from a 2026 single-country study, outcomes compare behavioural and attitudinal responses against standard-of-care materials (e.g., UNICEF infographics) to identify effective, scalable misinformation interventions.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The aim of this multi-country trial is to identify and quantify the effectiveness of inoculation strategies against vaccine-related misinformation. Building on a single-country study implemented in early 2026 [NCT07488962], the study evaluates an AI chatbot designed to counter cognitive biases, embedded within a larger survey to enable integrated assessment of engagement, behavioural responses, and system performance at scale.

The study will be conducted across five European countries-the United Kingdom, the Netherlands, Croatia, Latvia, and Slovakia-with a total sample of 5,000 parents or caregivers (n=1,000 per country). Participants will complete a structured survey assessing childhood vaccination behaviours, vaccine confidence, trust in information sources, exposure to misinformation, and relevant psychological and sociodemographic factors.

Participants will be randomly assigned to either the intervention or control arm. The intervention arm will receive the AI-based chatbot, while the control arm will receive standard-of-care materials-such as national or international health institute communications (e.g., UNICEF infographics)-that address the same misinformation messages, enabling a direct and rigorous comparison.

The primary outcome is parents' ability to correctly distinguish true from false childhood vaccine statements. Quantitative analyses will include pooled and country-specific models to identify determinants of vaccine confidence and estimate intervention effects. Findings will clarify drivers of declining vaccine confidence and assess whether a scalable AI-based chatbot can reduce vulnerability to misinformation and support informed vaccination decisions.

Study Type

Interventional

Enrollment (Estimated)

5000

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Parents or caregivers with children under 18 years old in the five target countries (UK, Netherlands, Croatia, Latvia, and Slovakia); and
  • Those who have regular access to a digital device and the internet

Exclusion Criteria:

  • Participants who do not meet the inclusion criteria.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Health Services Research
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: AI-driven chatbot
An interactive, web-based, AI-driven chatbot intervention designed to counter vaccine misinformation. It can be accessed via a personal computer, tablet, or mobile device through a web- browser link.
Behavioral: AI-driven chatbot
A tailored AI-driven chatbot designed to counter vaccine misinformation.
Active Comparator: Social media infographic
A UNICEF social media infographic with three "myth vs. fact" statements on vaccination that correspond to the same misinformation tactics explained by the MindShield chatbot.
Behavioral: Social media infographic
A UNICEF social media infographic with three "myth vs. fact" statements on vaccination.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Parental susceptibility to misinformation about childhood vaccination
Time Frame: Through study completion, an average of 20-30 minutes
The primary outcome of this study will assess parental susceptibility to misinformation about childhood vaccination, defined as parents' ability to accurately distinguish between true and false vaccine-related information. This will be measured using ten statements on childhood vaccines, including four true and six false, rumour-related statements. Two of the rumour-related statements correspond to each of the three misinformation tactics introduced by the chatbot and the UNICEF infographic. This measure reflects parents' ability to identify misinformation containing manipulation tactics they were inoculated against and to distinguish true from false information regarding childhood vaccination. Responses will be recorded as "True", "False", or "Don't know". A composite misinformation susceptibility score will be calculated based on the number of correct responses, with higher scores indicating greater ability to identify vaccine misinformation accurately.
Through study completion, an average of 20-30 minutes

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Self-efficacy
Time Frame: Through study completion, an average of 20-30 minutes
Participants' self-efficacy will be evaluated in two domains: (a) confidence in making informed vaccination decisions for their children, measured with a binary response of "Yes" or "No", and (b) confidence in seeking trustworthy information about childhood vaccinations, measured on a four-point scale from "Not at all confident" to "Very confident".
Through study completion, an average of 20-30 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

London School of Hygiene and Tropical Medicine

Investigators

  • Principal Investigator: Leesa Lin, PhD, London School of Hygiene and Tropical Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

April 1, 2026

Primary Completion (Estimated)

April 1, 2026

Study Completion (Estimated)

April 1, 2026

Study Registration Dates

First Submitted

April 20, 2026

First Submitted That Met QC Criteria

April 20, 2026

First Posted (Actual)

April 27, 2026

Study Record Updates

Last Update Posted (Actual)

May 1, 2026

Last Update Submitted That Met QC Criteria

April 27, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • LSHTM32877

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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