This proposed study aims to conduct timely research that promotes vaccine confidence and vaccination of one strongly recommended vaccine with suboptimal uptake rates: Human papillomavirus (HPV) in vulnerable and underserved youth aged 11-14.

The study objectives are:

Objective 1: Assess feasibility (participation rate, retention, involvement, satisfaction) of one game-based interventions targeting HPV vaccination.

Objective 2: Conduct a pilot RCT with three conditions (Arm 1: HPV game-based intervention; Arm 2: usual care). The investigators will explore patterns of pre- to post-intervention change in theoretical mediators and vaccine intent, and explore levels of vaccine intent and uptake in 90 parent-child dyads of unvaccinated youth aged 11-14.

Inclusion Criteria:

• Child sample: (1) 11-14 years old, (2) speaks and reads English, (3) has never received any doses of the HPV vaccine, (4) is not currently enrolled in another project that involves HPV-related education, and (5) agrees and provides assent to participate in research activities.
• Parent sample: (1) parent or legal guardian of the participating child, (2) speak and read English, (3) own a smartphone, (4) agree to receive email and text messages, (5) is not currently enrolled in another project that involves HPV-related education, and (6) agree and provide consent to participate in research activities.

Exclusion Criteria: Individuals who do not meet inclusion criteria or refuse to provide consent/assent.

De-identified, non-sensitive data will be deposited in Dryad no later than the date of publication.

Start: no later than the date of publication End: remain publicly available for 3 years following publication

All users will have open access to the data without restriction, consistent with Dryad's open-access model. Data can be accessed directly through Dryad's website using the assigned DOI, ensuring discoverability and persistent availability. No personally identifiable or sensitive information will be shared.