The primary objectives of this study are to increase HPV vaccination initiation and 3-dose completion among pediatric, adolescent, and young adult (PAYA) cancer survivors

PAYA cancer survivors are 2.8 times more likely to develop a secondary human papillomavirus (HPV)-associated cancer than the general population. Unfortunately, HPV vaccination coverage among PAYA cancer survivors is even lower than that in the general population. Provision of adequate vaccine information and instructions for timing of vaccination post-treatment is associated with an increased intention to vaccinate. Nonetheless, research show a minority of cancer care teams specifically discuss HPV vaccination with PAYA cancer survivors and their caregivers. The purpose of this study is to test the efficacy of an oncologist- and clinic-level intervention and the additional effect of a patient-level app-based intervention to improve initiation and 3-dose completion of the HPV vaccine series.

Inclusion Criteria:

• Current patient in the University of Minnesota CCSP clinic or the Children's Minnesota Long-Term Follow-up (LTFU) Program clinic.
• Patients seen in the CCSP clinic who do not have a history of cancer but who have received immunosuppressive therapy or HSCT for treatment of a hematologic disorder.
• Survivor of childhood cancer (defined as diagnosed with cancer at age 25 years or younger) who is currently 18-26 years of age OR a caregiver of a survivor of childhood cancer who is currently 9-17 years of age.
• 6+ months post-treatment; current treatment for graft-versus-host disease allowed
• No previous HPV vaccination or incomplete HPV vaccination (defined as <3 doses post-cancer therapy). Individuals who are unsure of their HPV vaccination status who are unable to find vaccination records per the procedures detailed in Section 5.2, EHR support will be eligible, in concordance with real-world clinical practice regarding HPV vaccination.

Exclusion Criteria:

• Previous completion of the HPV vaccination series. Those who are eligible for re-vaccination per the CDC guidelines will be encouraged by their oncologist to re-vaccinate, but will not be included in the QI study or RCT.
• Unable to read/write in English per self-report (only applies to participants in the RCT [Aim 2]).
• Pregnant at the time of enrollment or plans to become pregnant in the next year. Pregnancy test at the time of enrollment is not required if pregnancy not clinically suspected in concordance with clinical guidelines for HPV vaccine administration.
• Currently receiving treatment for cancer or hematologic disorder or plan for treatment within 12 months of enrollment; treatment for graft-versus-host disease allowed.
• Other contraindications to the HPV vaccine (e.g. history of immediate hypersensitivity reaction to any vaccine component, including yeast).

At the end of the study, the link between subjects' identifiable identification codes and their identifiable information will be destroyed per the AHC protocol at the time of data disposal. The original data records will be archived for 7 years (in accordance with data practices).