HPV Vaccination Intent
Conditions
Keywords
chatbot, artificial intelligence, large language models, HPV vaccine
Brief 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. 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.
Interventions
BEHAVIORALDefault-style LLM chatbot
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.
BEHAVIORALConversational-style LLM chatbot
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.
BEHAVIORALPublic health informational materials
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.
Sponsors
University of Pennsylvania
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* 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
Exclusion criteria
* Failure to pass attention checks * Identified as non-human respondents by reCAPTCHA or other automated bot detection
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in intent to vaccinate child against HPV within the next 12 months | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in intent to vaccinate child against HPV at 45-day follow-up | Baseline to 45 days post-intervention | 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. |
| Change in general parental vaccine hesitancy (PACV-5) | Baseline to immediately post-intervention | Change in scores on the 5-item Parent Attitudes about Childhood Vaccines (PACV-5) scale. Measured at baseline and immediately after the intervention. |
| Change in intent to vaccinate child for influenza and COVID-19 | Measured at baseline and immediately post-intervention. | 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. |
| Change in importance ratings of HPV vaccine concerns | Baseline to immediately post-intervention | 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. |
| Change in intent to vaccinate child against HPV at 15-day follow-up | Baseline to 15 days post-intervention | 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. |
| Willingness to donate payment to vaccine education charity | Immediately post-intervention | Percentage of survey payment participants choose to donate (0%, 10%, 30%, or 50%) to an immunization-related charity during the post-intervention survey. |
| Willingness to be recontacted for future research | Immediately post-intervention | Participant self-reported willingness (yes/no) to be contacted for future studies |
| Ratings of empathy, usefulness, and relevance of intervention content | Immediately post-intervention | Participant ratings (1-5 scale) of how empathetic, useful, and relevant they found the assigned chatbot conversation or public health reading material. |
| Clicks on HPV vaccine appointment scheduling link | Immediately post-intervention | Whether participants click a provided link to schedule an HPV vaccine appointment through CVS during the post-intervention survey. |
Countries
United States
Outcome results
None listed