HPV Vaccination IntentNCT07132125
Conversations With AI Chatbots Increase Short-Term Vaccine Intentions But Do Not Outperform Standard Public Health Messaging
A study testing Default-style LLM chatbot, Conversational-style LLM chatbot and Public health informational materials in people with HPV Vaccination Intent, run by University of Pennsylvania at 1 site in United States.
Trial summary
The goal of this clinical trial is to test whether short conversations with large language model (LLM) chatbots can persuade vaccine-hesitant parents to vaccinate their children against human papillomavirus (HPV). The study compares two chatbot styles to official public health information and to a no-message control. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- HPV Vaccination Intent
- What is being tested?
- Default-style LLM chatbot, Conversational-style LLM chatbot and Public health informational materials
- Type of treatment
- Vaccines, Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 930 participants
- Where
- 1 siteUnited States
- Study dates
- 17 Mar 2025to 22 May 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adults aged 18 years and up
- Living in Canada, the UK, or the USA
- At least one child eligible for HPV vaccine based on country-specific guidelines who has not received any doses of the vaccine or whose vaccination status is unknown
Who cannot join
- Failure to pass attention checks
- Identified as non-human respondents by reCAPTCHA or other automated bot detection
Trial locations and contacts
1 site in 1 country.
United States1 site
Participants are recruited online via Prolific
Philadelphia, Pennsylvania, 19104
About this study
The goal of this clinical trial is to test whether short conversations with large language model (LLM) chatbots can persuade vaccine-hesitant parents to vaccinate their children against human papillomavirus (HPV). The study compares two chatbot styles to official public health information and to a no-message control. Parents of HPV-eligible children first complete a survey about their attitudes toward the HPV vaccine and their main concerns. They are then randomly assigned to read public health materials, have a three-minute conversation with either a default-style chatbot or a conversational-style chatbot tailored to their concern, or receive no message. The main outcome is change in intent to vaccinate immediately after the intervention, with follow-up surveys at 15 and 45 days.
- Conditions
- HPV Vaccination Intent
- Being tested
- Default-style LLM chatbot, Conversational-style LLM chatbot, Public health informational materials
- Keywords
- chatbot, artificial intelligence, large language models, HPV vaccine
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Default-style LLM chatbotBehavioural
A large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination, using the model's default style with longer, structured responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey.
Conversational-style LLM chatbotBehavioural
A large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination in a conversational style, with short responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey.
Public health informational materialsBehavioural
Official public health informational materials on HPV vaccination from the Centers for Disease Control and Prevention (U.S.), National Health Service (U.K.), or Public Health Agency of Canada, matched to the participant's country of residence. Materials are 589-680 words in length, cover HPV risks and benefits of vaccination, and are presented for three minutes before participants proceed.
| Study group | Role | What they receive |
|---|---|---|
| Default-style LLM chatbot | Experimental | A large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination, using the model's default style with longer, structured responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey. Receives: Behavioral: Default-style LLM chatbot |
| Conversational-style LLM chatbot | Experimental | A large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination in a conversational style, with short responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey. Receives: Behavioral: Conversational-style LLM chatbot |
| Public health informational materials | Active comparator | Official public health informational materials on HPV vaccination from the Centers for Disease Control and Prevention (U.S.), National Health Service (U.K.), or Public Health Agency of Canada, matched to the participant's country of residence. Materials are 589-680 words in length, cover HPV risks and benefits of vaccination, and are presented for three minutes before participants proceed. Receives: Behavioral: Public health informational materials |
| No Message | No intervention | No Intervention |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in intent to vaccinate child against HPV within the next 12 months
Self-reported likelihood, on a 0-100 scale, of vaccinating the participant's youngest HPV vaccine-eligible child (identified in pre-survey) within the next 12 months. Measured before and immediately after the intervention to assess short-term changes in vaccination intent.
Measured: Baseline to immediately post-intervention
Secondary outcomes (9)
Change in intent to vaccinate child against HPV at 15-day follow-up
Self-reported likelihood, on a 0-100 scale, of vaccinating the participant's youngest HPV vaccine-eligible child within the next 12 months. Measured at baseline and 15 days after the intervention to assess durability of effects.
Measured: Baseline to 15 days post-intervention
Change in intent to vaccinate child against HPV at 45-day follow-up
Self-reported likelihood, on a 0-100 scale, of vaccinating the participant's youngest HPV vaccine-eligible child within the next 12 months. Measured at baseline and 45 days after the intervention to assess durability of effects.
Measured: Baseline to 45 days post-intervention
Change in general parental vaccine hesitancy (PACV-5)
Change in scores on the 5-item Parent Attitudes about Childhood Vaccines (PACV-5) scale. Measured at baseline and immediately after the intervention.
Measured: Baseline to immediately post-intervention
Change in intent to vaccinate child for influenza and COVID-19
Self-reported likelihood, on a 0-100 scale, of vaccinating the participant's youngest eligible child for influenza or COVID-19 within the next 12 months.
Measured: Measured at baseline and immediately post-intervention.
Change in importance ratings of HPV vaccine concerns
Change in participant ratings (0-100 scale) of importance for each HPV vaccine concern (list derived from National Immunization Surveys) between baseline and immediately post-intervention.
Measured: Baseline to immediately post-intervention
Clicks on HPV vaccine appointment scheduling link
Whether participants click a provided link to schedule an HPV vaccine appointment through CVS during the post-intervention survey.
Measured: Immediately post-intervention
Willingness to donate payment to vaccine education charity
Percentage of survey payment participants choose to donate (0%, 10%, 30%, or 50%) to an immunization-related charity during the post-intervention survey.
Measured: Immediately post-intervention
Willingness to be recontacted for future research
Participant self-reported willingness (yes/no) to be contacted for future studies
Measured: Immediately post-intervention
Ratings of empathy, usefulness, and relevance of intervention content
Participant ratings (1-5 scale) of how empathetic, useful, and relevant they found the assigned chatbot conversation or public health reading material.
Measured: Immediately post-intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Aug 2025
- Study start17 Mar 2025
- Primary completion22 May 2025
- Study completion22 May 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for HPV Vaccination IntentStudies of the same condition, open and under way.
- More trials run by University of PennsylvaniaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 930 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Pennsylvania
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07132125
- Sponsor's protocol ID
- LLM_857299
- Status last verified
- Aug 2025
- First submitted
- 12 Aug 2025
- Last updated
- 20 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes
Publications
Sehgal NKR, Rai S, Tonneau M, Agarwal AK, Cappella J, Kornides ML, Ungar L, Buttenheim A, Guntuku SC. Large Language Model Chatbot Conversations vs Public Health Materials and Parental HPV Vaccination Intentions: A Randomized Clinical Trial. JAMA Netw Open. 2026 Jun 1;9(6):e2616822. doi: 10.1001/jamanetworkopen.2026.16822.
PubMed 42258213
Study at a glance
From the registry record, last updated by the sponsor on 20 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Conversations With AI Chatbots Increase Short-Term Vaccine Intentions But Do Not Outperform Standard Public Health Messaging
- ClinicalTrials.gov ID
- NCT07132125
- Acronym / sponsor ID
- LLM_857299
- Conditions
- HPV Vaccination Intent
- Keywords
- chatbot, artificial intelligence, large language models, HPV vaccine
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 930 participants (actual)
- Lead sponsor
- University of PennsylvaniaUniversity, hospital or other
- Study start
- 17 Mar 2025 (actual)
- Primary completion
- 22 May 2025 (actual)
- Study completion
- 22 May 2025 (actual)
- First posted
- 20 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to test whether short conversations with large language model (LLM) chatbots can persuade vaccine-hesitant parents to vaccinate their children against human papillomavirus (HPV). The study compares two chatbot styles to official public health information and to a no-message control. Parents of HPV-eligible children first complete a survey about their attitudes toward the HPV vaccine and their main concerns. They are then randomly assigned to read public health materials, have a three-minute conversation with either a default-style chatbot or a conversational-style chatbot tailored to their concern, or receive no message. The main outcome is change in intent to vaccinate immediately after the intervention, with follow-up surveys at 15 and 45 days.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Default-style LLM chatbot | Experimental | Behavioral: Default-style LLM chatbotA large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination, using the model's default style with longer, structured responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey. |
| Conversational-style LLM chatbot | Experimental | Behavioral: Conversational-style LLM chatbotA large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination in a conversational style, with short responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey. |
| Public health informational materials | Active comparator | Behavioral: Public health informational materialsOfficial public health informational materials on HPV vaccination from the Centers for Disease Control and Prevention (U.S.), National Health Service (U.K.), or Public Health Agency of Canada, matched to the participant's country of residence. Materials are 589-680 words in length, cover HPV risks and benefits of vaccination, and are presented for three minutes before participants proceed. |
| No Message | No intervention | –No Intervention |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Adults aged 18 years and up
- Living in Canada, the UK, or the USA
- At least one child eligible for HPV vaccine based on country-specific guidelines who has not received any doses of the vaccine or whose vaccination status is unknown
Key exclusion criteria (2 listed)
- Failure to pass attention checks
- Identified as non-human respondents by reCAPTCHA or other automated bot detection
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Default-style LLM chatbotA large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination, using the model's default style with longer, structured responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey. | Behavioural | Default-style LLM chatbot |
| Conversational-style LLM chatbotA large language model chatbot (GPT-4o) that delivers tailored persuasive messages to parents about HPV vaccination in a conversational style, with short responses. Participants engage in a three-minute, multi-turn conversation, with responses personalized to their top-rated vaccine concern identified in a pre-intervention survey. | Behavioural | Conversational-style LLM chatbot |
| Public health informational materialsOfficial public health informational materials on HPV vaccination from the Centers for Disease Control and Prevention (U.S.), National Health Service (U.K.), or Public Health Agency of Canada, matched to the participant's country of residence. Materials are 589-680 words in length, cover HPV risks and benefits of vaccination, and are presented for three minutes before participants proceed. | Behavioural | Public health informational materials |
Primary outcome
Change in intent to vaccinate child against HPV within the next 12 months
Time frame: Baseline to immediately post-intervention
Self-reported likelihood, on a 0-100 scale, of vaccinating the participant's youngest HPV vaccine-eligible child (identified in pre-survey) within the next 12 months. Measured before and immediately after the intervention to assess short-term changes in vaccination intent.
9 secondary outcomes
Change in intent to vaccinate child against HPV at 15-day follow-up
Time frame: Baseline to 15 days post-intervention
Change in intent to vaccinate child against HPV at 45-day follow-up
Time frame: Baseline to 45 days post-intervention
Change in general parental vaccine hesitancy (PACV-5)
Time frame: Baseline to immediately post-intervention
Change in intent to vaccinate child for influenza and COVID-19
Time frame: Measured at baseline and immediately post-intervention.
Change in importance ratings of HPV vaccine concerns
Time frame: Baseline to immediately post-intervention
Clicks on HPV vaccine appointment scheduling link
Time frame: Immediately post-intervention
Willingness to donate payment to vaccine education charity
Time frame: Immediately post-intervention
Willingness to be recontacted for future research
Time frame: Immediately post-intervention
Ratings of empathy, usefulness, and relevance of intervention content
Time frame: Immediately post-intervention
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Aug 2025.
- Derived from this study: PubMed 42258213Sehgal NKR, Rai S, Tonneau M, Agarwal AK, Cappella J, Kornides ML, Ungar L, Buttenheim A, Guntuku SC. Large Language Model Chatbot Conversations vs Public Health Materials and Parental HPV Vaccination Intentions: A Randomized Clinical Trial. JAMA Netw Open. 2026 Jun 1;9(6):e2616822. doi: 10.1001/jamanetworkopen.2026.16822.
- Individual participant dataSharing planned: Yes
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Default-style LLM chatbot, Conversational-style LLM chatbot and Public health informational materials in people with HPV Vaccination Intent, run by University of Pennsylvania at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 20 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in intent to vaccinate child against HPV within the next 12 months (time frame: Baseline to immediately post-intervention). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07132125, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Aug 2025; AzTrials last refreshed its copy on 6 Nov 2026.