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

April 3, 2026 updated by: The University of Texas Medical Branch, Galveston
The investigators are evaluating whether 15-26 year old males and females need a 3rd dose of the human papillomavirus (HPV) vaccine, or whether 2 doses provide similar protection as 3 doses from the 9 types of HPV that it protects against.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The investigators are studying an amended dosing regimen of an approved drug (Gardasil 9) in the population for which it is approved (vaccine is approved for ages 9-45 years and participants in this study will be 15-26 years of age.) The purpose of the study is to examine a delayed dosing schedule. The current recommendation is to administer the vaccine in 3 doses (administered at 0, 1-2 months and 6 months) to those 15-26 years of age but only 2 doses (0 and 6 months) if given at 9-14 years of age. The investigators will conduct a randomized study to determine if 2 doses will elicit an immune response similar to the standard 3 doses in those 15-26 years of age. Participants in the study group will receive 2 doses of Gardasil 9 at 0 and 6 months. Participants in the control group will receive 3 doses of Gardasil 9 at 0, 1-2 months and 6 months. All participants (Target Accrual n=512) will have 5 mLs of blood drawn at 0, 7, and 12 months. Following the 12 month blood draw, participants randomized to 2-doses will receive the 3rd dose. Potential participants will be recruited in the University of Texas Medical Branch (UTMB) clinics where providers have given the PI permission to directly contact patients. The investigators will also display signs and use email announcements at UTMB and other college campuses and will advertise the study online or by mail. The investigators will call UTMB patients if their provider gave permission to contact the patient, or if the patients gave prior consent to contact through the UTMB system. Potential participants (and their parents, if under 18 years of age) will be screened with inclusion/exclusion criteria. Eligible and interested parents and patients will sign informed written consent. Patients under 18 years of age will sign written assent. At the initial visit, eligible, consented participants will have their blood drawn, be randomized into either the study or control group, and receive a dose of the HPV vaccine. Participants will be re-screened against the inclusion/exclusion criteria at subsequent visits. All participants will receive compensation administered through a ClinCard following each of the 3 blood draws.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
767

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Abbey B Berenson, MD, PhD
  • Phone Number: 409-772-2417
  • Email: abberens@utmb.edu

Study Contact Backup

Study Locations

  • United States
    • Texas
      • Galveston, Texas, United States, 77555
        • University of Texas Medical Branch

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

15 years to 26 years (Child, Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Males and females 15-26 years old.
  2. Ability to give informed consent. All participants under 18 years of age must have the informed consent of a parent and must assent to participation.
  3. Has not received any prior doses of the HPV vaccine. Investigators will ask the patient and his/her parent (if <18) about prior vaccination and check the state registry (Immtrac), as well as the UTMB electronic medical record (if previously seen at UTMB), investigators will check with their primary care provider, if feasible, for patients who are not a previously established UTMB patient.
  4. Identified source of funding for vaccine which may include Texas Vaccines for Children (VFC) program, Medicaid, the Children's Health Insurance Plan (CHIP), Texas Healthy 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 or Spanish.

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 each Gardasil 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 the study and advised to seek prenatal care. If a subject is pregnant when her follow-up visit 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 systemic corticosteroids, radiation therapy, cyclophosphamide, azathioprine, methotrexate, cyclosporine, leflunomide, TNF-alpha antagonists, monoclonal antibody therapies, or intravenous immunoglobulin treatment.
  6. Known allergies to any components of the vaccine, including aluminum, yeast or Benzonase.
  7. Febrile at ≥100°F in the 24 hours prior to vaccination. This will be reviewed before each Gardasil 9 dose.
  8. Received any non-study inactive vaccines within the past 14 days or any live vaccines within the past 30 days. Those excluded for this reason will be re-screened under the same study number at a later date.
  9. Plan to move out of the Galveston/Houston area in the 13 months following study entry.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Females, 3 dose standard
Three doses of the 9-valent HPV vaccine to be administered to the comparison group (15-26 years of age) at 0, 2, and 6 months.
Biological: 9-valent HPV vaccine, 3 doses standard timing
Will be comparison group for 2 dose efficacy group.
Experimental: Females, 2 dose with delayed 3rd dose
Two doses of the 9-valent HPV vaccine to be administered to the experimental group (15-26 years of age) at 0 and 6 months. Additional HPV vaccine dose will be offered after final blood draw at 12 months.
Biological: 9-valent HPV vaccine, 2 dose efficacy
Evaluate the efficacy of 2 doses of the HPV vaccine across a 12 month period following the 1st dose among 15-26 year old males and females.
Active Comparator: Males, 3 dose standard
Three doses of the 9-valent HPV vaccine to be administered to the comparison group (15-26 years of age) at 0, 2, and 6 months.
Biological: 9-valent HPV vaccine, 3 doses standard timing
Will be comparison group for 2 dose efficacy group.
Experimental: Males, 2 dose with delayed 3rd dose
Two doses of the 9-valent HPV vaccine to be administered to the experimental group (15-26 years of age) at 0 and 6 months. Additional HPV vaccine dose will be offered after final blood draw at 12 months.
Biological: 9-valent HPV vaccine, 2 dose efficacy
Evaluate the efficacy of 2 doses of the HPV vaccine across a 12 month period following the 1st dose among 15-26 year old males and females.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Short-term Human Papillomavirus (HPV) Type-specific Antibody Response for Type HPV-6
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 6, measured as % of participants who seroconvert
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-11
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 11, measured as measured as % of participants who seroconvert.
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-16
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 16, measured as % of participants who seroconvert
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-18
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 18, measured as % of participants who seroconvert
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-31
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 31, measured as % of participants who seroconvert
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-33
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 33, measured as % of participants who seroconvert
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-45
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 45, measured as % of participants who seroconvert
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-52
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 52, measured as % of participants who seroconvert
Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-58
Time Frame: Month 7
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 58, measured as % of participants who seroconvert
Month 7
HPV Type-specific Antibody Response for Type HPV-6
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 6, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-11
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 11, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-16
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 16, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-18
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 18, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-31
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 31, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-33
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 33, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-45
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 45, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-52
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 52, measured as % of participants who seroconvert
Month 12
HPV Type-specific Antibody Response for Type HPV-58
Time Frame: Month 12
Yes/No for seroconversion, defined as changing from seronegative (no detectable antibodies) to seropositive (antibodies at or exceeding natural immunity levels) to HPV type 58, measured as % of participants who seroconvert
Month 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
The University of Texas Medical Branch, Galveston

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Cancer Prevention Research Institute of Texas

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Abbey B Berenson, MD, PhD, University of Texas

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 17, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 13, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 13, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 7, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 7, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 9, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 3, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 19-0058
  • RP190022 (Other Grant/Funding Number: Cancer Prevention & Research Institute of Texas)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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