Combining an Effective Rule-based Chatbot With ChatGPT-supported Real-time Question-answer Functions to Promote Seasonal Influenza Vaccination Among Community-dwelling People Aged 65 Years and Above

November 8, 2026 updated by: Zixin Wang, Chinese University of Hong Kong

Combining an Effective Rule-based Chatbot With ChatGPT-supported Real-time Question-answer Functions to Promote Seasonal Influenza Vaccination Among Community-dwelling People Aged 65 Years and Above: a Partially Blinded Randomized Controlled Trial

This study is a partially blinded (outcome assessors and data analysts) and parallel-group randomized controlled trial. Community-dwelling people aged ≥65 years who have not received the SIV for the approaching flu season will be randomized evenly (1:1) into either the intervention group or the control group. During the intervention period, the intervention group will have access to the hybrid combination of a rule-based chatbot (SIV-Chatbot) with the ChatGPT-supported real-time Question & Answer (QA) functions, while the control group will have access only to the SIV-Chatbot.

The SIV-Chatbot will deliver the same interventions for both groups. The number of intervention sessions (four) and timing (week 0, 2, 4 & 6) will also be the same. In the intervention group, the hybrid Chatbot will invite the participants to raise open-ended questions related to SIV using flexible methods (such as voice messages, typing with keyboards, or handwriting) at each session. The ChatGPT will answer these questions immediately in the format of text messages. The functions can be used repeatedly throughout the intervention period (weeks 0-6), and participants will be free to spend as much time as they want on such functions.

Telephone interviews will be conducted at baseline (T0), after completion of the intervention (T1), and six months after T1 (T2). The primary outcome will be the self-reported SIV uptake measured at T2. The research team will validate that outcome by requesting the participants upload an image of their SIV receipt, while hiding their personal identification, via the WhatsApp account used in this study.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
454

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

65 years and older (Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • aged ≥65 years
  • possession of a Hong Kong ID
  • able to speak and comprehend Cantonese
  • have a smartphone with internet access
  • have either installed or are willing to install WhatsApp on their smartphone
  • have not taken seasonal influenza vaccination for the approaching flu season

Exclusion Criteria:

  • score ≤16 in the validated telephone version of the Cantonese Mini-Mental State Examination (T-CMMSE)
  • either blindness or deafness
  • with known contraindications to the SIV as indicated by the Hong Kong Centre for Health Protection (e.g., history of severe allergic reactions to any of the vaccine component or a previous dose of SIV and bleeding disorders)

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: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Intervention group

Have access to the hybrid combination of a rule-based chatbot (SIV-Chatbot) with the ChatGPT-supported real-time QA functions
Behavioral: Hybrid chatbot

After assessing participants' stage of change (SOC) regarding SIV uptake, the rule-based component (SIV-Chatbot) will deliver online interventions tailored to their current SOC. There will be four intervention sessions at week 0, 2, 4 and 6. In addition, the hybrid Chatbot will invite the participants to raise open-ended questions related to SIV using flexible methods at each session. The ChatGPT will answer these questions immediately in the format of text messages. The functions can be used repeatedly throughout the intervention period (weeks 0-6), and participants will be free to spend as much time as they want on such functions.
Active Comparator: Control group

Have access only to a rule-based chatbot (SIV-Chatbot)
Behavioral: Rule-based chatbot

After assessing participants' stage of change (SOC) regarding SIV uptake, the rule-based chatbot (SIV-Chatbot) will deliver online interventions tailored to their current SOC. There will be four intervention sessions at week 0, 2, 4 and 6.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Uptake of seasonal influenza vaccination
Time Frame: Six months after completion of the intervention

The primary outcome will be the self-reported seasonal influenza vaccination uptake measured at T2 (six months after completion of the intervention). The research team will validate that outcome by requesting the participants upload an image of their receipt.
Six months after completion of the intervention

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Stage of change related to seasonal influenza vaccination uptake
Time Frame: T0 (baseline), T1 (after completion of intervention), and T2 (six months after completion of the intervention)

Participants' SOC will be measured at T0 (baseline), T1 (after completion of intervention), and T2 (six months after completion of the intervention) by using validated questions
T0 (baseline), T1 (after completion of intervention), and T2 (six months after completion of the intervention)
Knowledge and attitudes related to seasonal influenza vaccination
Time Frame: T0 (baseline) and T2 (6 months after completion of the intervention)

Knowledge and attitudes will be measured at T0 (baseline) and T2 (6 months after completion of the intervention) by validated tools
T0 (baseline) and T2 (6 months after completion of the intervention)

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Chinese University of Hong Kong

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 16, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 8, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 13, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • GRF14611325

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The data presented in this study are available from the corresponding author upon request. The data are not publicly available as they contain sensitive personal information.

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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