GARDASIL 9: 3 Dose vs. 2 Dose With Delayed 3rd Dose

Inclusion Criteria:

1. Males and females 15-26 years old.

2. Ability to give informed consent. All participants under 18 years of age must havethe informed consent of a parent and must assent to participation.

3. Has not received any prior doses of the HPV vaccine. We will ask the patient andhis/her parent (if <18) about prior vaccination and check the state registry (Immtrac), as well as the UTMB electronic medical record (if previously seen atUTMB), We will check with their primary care provider, if feasible, for patients whoare not a previously established UTMB patient.

4. Identified source of funding for vaccine which may include Texas Vaccines forChildren (VFC) program, Medicaid, the Children's Health Insurance Plan (CHIP), TexasHealthy Women program or other public or private health insurance.

5. Reliable telephone access.

6. Participant and parent/ guardian (if <18) can read and speak either English orSpanish.

Exclusion Criteria:

1. For females, currently pregnant or plans to become pregnant or donate eggs in next 12 months. Sexually active females must report that they use regular birth control.All female subjects will be required to take a urine pregnancy test before eachGardasil 9 dose, unless it can be verified that she gave birth within the last week.Any subjects with positive tests at the initial visit will be disqualified from thestudy and advised to seek prenatal care. If a subject is pregnant when her follow-upvisit window closes, she will be removed from the study.

2. History of 6 or more lifetime sexual partners.

3. History of any immunodeficiencies (HIV+, chemotherapy treatment, status splenectomy)or autoimmune disorders (lupus, thyroid disorder, psoriasis).

4. History of bleeding or platelet disorders such as hemophilia.

5. Currently taking medication which can suppress immune function including systemiccorticosteroids, radiation therapy, cyclophosphamide, azathioprine, methotrexate,cyclosporine, leflunomide, TNF-alpha antagonists, monoclonal antibody therapies, orintravenous immunoglobulin treatment.

6. Known allergies to any components of the vaccine, including aluminum, yeast orBenzonase.

7. Febrile at ≥100°F in the 24 hours prior to vaccination. This will be reviewed beforeeach Gardasil 9 dose.

8. Received any non-study inactive vaccines within the past 14 days or any livevaccines within the past 30 days. Those excluded for this reason will be re-screenedunder the same study number at a later date.

9. Plan to move out of the Galveston/Houston area in the 13 months following studyentry.