ImmunizationPhase 4NCT03943875

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

A Phase 4 study testing 9-valent HPV vaccine, 2 dose efficacy and 9-valent HPV vaccine, 3 doses standard timing in people with Immunization and Efficacy, run by The University of Texas Medical Branch, Galveston at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

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. Read more about this study

Who is it for?: Ages 15 to 26 yearsHealthy volunteers can take part
Conditions the study is for: Immunization, Efficacy, Human Papilloma Virus
What is being tested?: 9-valent HPV vaccine, 2 dose efficacy and 9-valent HPV vaccine, 3 doses standard timing
Type of treatment: Vaccines
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 767 participants
Where: 1 siteUnited States
Study dates: 17 Jun 2019to 13 Jan 2025
Phase: Phase 4
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 15 to 26 years
All sexes
Healthy volunteers accepted
Child, Adult

Who may be able to join

Males and females 15-26 years old.
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.
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.
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.
Reliable telephone access.
Participant and parent/ guardian (if <18) can read and speak either English or Spanish.

Who cannot join

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.
History of 6 or more lifetime sexual partners.
History of any immunodeficiencies (HIV+, chemotherapy treatment, status splenectomy) or autoimmune disorders (lupus, thyroid disorder, psoriasis).
History of bleeding or platelet disorders such as hemophilia.
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.
Known allergies to any components of the vaccine, including aluminum, yeast or Benzonase.

Show all 9Show fewer

Febrile at ≥100°F in the 24 hours prior to vaccination. This will be reviewed before each Gardasil 9 dose.
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.
Plan to move out of the Galveston/Houston area in the 13 months following study entry.

Trial locations and contacts

1 site in 1 country.

United States1 site

University of Texas Medical Branch
Galveston, Texas, 77555

Other trials in United States

About this study

Read the 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.

Conditions: Immunization, Efficacy, Human Papilloma Virus
Being tested: 9-valent HPV vaccine, 2 dose efficacy, 9-valent HPV vaccine, 3 doses standard timing
Keywords: HPV vaccination, Gardasil 9, vaccine efficacy

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

9-valent HPV vaccine, 2 dose efficacyBiological
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.
9-valent HPV vaccine, 3 doses standard timingBiological
Will be comparison group for 2 dose efficacy group.

Study groups in NCT03943875
Study group	Role	What they receive
Females, 3 dose standard	Active comparator	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. Receives: Biological: 9-valent HPV vaccine, 3 doses standard timing
Females, 2 dose with delayed 3rd dose	Experimental	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. Receives: Biological: 9-valent HPV vaccine, 2 dose efficacy
Males, 3 dose standard	Active comparator	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. Receives: Biological: 9-valent HPV vaccine, 3 doses standard timing
Males, 2 dose with delayed 3rd dose	Experimental	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. Receives: Biological: 9-valent HPV vaccine, 2 dose efficacy

What is being measured

The primary outcome is the main question the study is designed to answer.

Short-term Human Papillomavirus (HPV) Type-specific Antibody Response for Type HPV-6
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
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-11
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.
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-16
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
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-18
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
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-31
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
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-33
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
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-45
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
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-52
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
Measured: Month 7
Short-term HPV Type-specific Antibody Response for Type HPV-58
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
Measured: Month 7
HPV Type-specific Antibody Response for Type HPV-6
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-11
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-16
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-18
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-31
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-33
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-45
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-52
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
Measured: Month 12
HPV Type-specific Antibody Response for Type HPV-58
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
Measured: Month 12

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

17 Jun 201913 Jan 2025

First posted9 May 2019
Study start17 Jun 2019
Primary completion13 Jan 2025
Study completion13 Jan 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (2)Papers the sponsor has linked to this study.
Other trials for ImmunizationStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 4
Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind
Who is masked: Outcomes assessor
Enrolment: 767 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT03943875
Sponsor's protocol ID: 19-0058
Other IDs: RP190022
Status last verified: Apr 2026
First submitted: 7 May 2019
Last updated: 16 Apr 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No

Publications

Bergman H, Henschke N, Arevalo-Rodriguez I, Buckley BS, Crosbie EJ, Davies JC, Dwan K, Golder SP, Loke YK, Probyn K, Petkovic J, Villanueva G, Morrison J. Human papillomavirus (HPV) vaccination for the prevention of cervical cancer and other HPV-related diseases: a network meta-analysis. Cochrane Database Syst Rev. 2025 Nov 24;11(11):CD015364. doi: 10.1002/14651858.CD015364.pub2.
PubMed 41276263
Berenson AB, Panicker G, Unger ER, Rupp RE, Kuo YF. Immunogenicity of 2 or 3 Doses of 9vHPV Vaccine in U.S. Female Individuals 15 to 26 Years of Age. NEJM Evid. 2024 Feb;3(2):EVIDoa2300194. doi: 10.1056/EVIDoa2300194. Epub 2024 Jan 23.
PubMed 38320488

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 16 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: GARDASIL 9: 3 Dose vs. 2 Dose With Delayed 3rd Dose
ClinicalTrials.gov ID: NCT03943875
Acronym / sponsor ID: 19-0058
Conditions: Immunization, Efficacy, Human Papilloma Virus
Keywords: HPV vaccination, Gardasil 9, vaccine efficacy
Phase: Phase 4
Study type: Interventional
Recruitment status: Completed
Enrolment: 767 participants (actual)
Lead sponsor: The University of Texas Medical Branch, GalvestonUniversity, hospital or other
Collaborators: Cancer Prevention Research Institute of Texas
Study start: 17 Jun 2019 (actual)
Primary completion: 13 Jan 2025 (actual)
Study completion: 13 Jan 2025 (actual)
First posted: 9 May 2019 (actual)
Results: Posted 17 Feb 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind (outcomes assessor)
Number of arms: 4

Arm	Type	Receives
Females, 3 dose standard	Active comparator	Biological: 9-valent HPV vaccine, 3 doses standard timingThree 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.
Females, 2 dose with delayed 3rd dose	Experimental	Biological: 9-valent HPV vaccine, 2 dose efficacyTwo 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.
Males, 3 dose standard	Active comparator	Biological: 9-valent HPV vaccine, 3 doses standard timingThree 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.
Males, 2 dose with delayed 3rd dose	Experimental	Biological: 9-valent HPV vaccine, 2 dose efficacyTwo 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.

Who may qualify

Ages: 15 to 26 years
Sex: All
Healthy volunteers: Accepted
Age groups: Child, Adult

Key inclusion criteria (6 listed)

Males and females 15-26 years old.
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.
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.
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.
Reliable telephone access.

Key exclusion criteria (9 listed)

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.
History of 6 or more lifetime sexual partners.
History of any immunodeficiencies (HIV+, chemotherapy treatment, status splenectomy) or autoimmune disorders (lupus, thyroid disorder, psoriasis).
History of bleeding or platelet disorders such as hemophilia.
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.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
9-valent HPV vaccine, 2 dose efficacyEvaluate 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.	Biological	Females, 2 dose with delayed 3rd dose, Males, 2 dose with delayed 3rd dose
9-valent HPV vaccine, 3 doses standard timingWill be comparison group for 2 dose efficacy group.	Biological	Females, 3 dose standard, Males, 3 dose standard

Primary outcome

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
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.
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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

Results and safety

Results posted to the registry on 17 Feb 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Females, 3 Dose Standard	221	168
Females, 2 Dose With Delayed 3rd Dose	217	173
Males, 3 Dose Standard	165	140
Males, 2 Dose With Delayed 3rd Dose	164	130

Primary outcome: Short-term Human Papillomavirus (HPV) Type-specific Antibody Response for Type HPV-6

Time frame: Month 7. Number (95% Confidence Interval). Unit: % of participants with seroconversion

Measure	Females, 3 Dose Standard n = 133	Females, 2 Dose With Delayed 3rd Dose n = 133	Males, 3 Dose Standard n = 123	Males, 2 Dose With Delayed 3rd Dose n = 111
Value	99.25 (95.88 to 99.98)	100.00 (97.26 to 100.000)	100.00 (97.05 to 100.00)	100.00 (96.73 to 100.00)

Population analysed: The per-protocol population only includes participants meeting the following criteria: the participant received all vaccine injections within the predetermined time ranges, adequate serum samples were collected at the appropriate time intervals, and the participant was seronegative at baseline for the HPV type being analyzed. Therefore, the number of participants analyzed will vary for each HPV type being analyzed.

Primary outcome: Short-term HPV Type-specific Antibody Response for Type HPV-11

Time frame: Month 7. Number (95% Confidence Interval). Unit: % of participants with seroconversion

Measure	Females, 3 Dose Standard n = 134	Females, 2 Dose With Delayed 3rd Dose n = 136	Males, 3 Dose Standard n = 124	Males, 2 Dose With Delayed 3rd Dose n = 111
Value	99.25 (95.91 to 99.98)	100.00 (97.32 to 100.00)	100.00 (97.07 to 100.00)	100.00 (96.73 to 100.00)

Primary outcome: Short-term HPV Type-specific Antibody Response for Type HPV-16

Time frame: Month 7. Number (95% Confidence Interval). Unit: % of participants with seroconversion

Measure	Females, 3 Dose Standard n = 118	Females, 2 Dose With Delayed 3rd Dose n = 121	Males, 3 Dose Standard n = 112	Males, 2 Dose With Delayed 3rd Dose n = 103
Value	99.15 (95.37 to 99.98)	100.00 (97.00 to 100.00)	100.00 (96.76 to 100.00)	100.00 (96.48 to 100.00)

Primary outcome: Short-term HPV Type-specific Antibody Response for Type HPV-18

Time frame: Month 7. Number (95% Confidence Interval). Unit: % of participants with seroconversion

Measure	Females, 3 Dose Standard n = 140	Females, 2 Dose With Delayed 3rd Dose n = 133	Males, 3 Dose Standard n = 122	Males, 2 Dose With Delayed 3rd Dose n = 115
Value	99.29 (96.08 to 99.98)	100.00 (97.26 to 100.00)	100.00 (97.02 to 100.00)	100.00 (96.84 to 100.00)

Adverse events

Time frame: Adverse event data were collected beginning with the initial inoculation through 6 weeks after administration of the final dose (30 weeks). Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Females, 3 Dose Standard	0 of 221 (0%)	0 of 221 (0%)	0 of 221
Females, 2 Dose With Delayed 3rd Dose	0 of 217 (0%)	0 of 217 (0%)	0 of 217
Males, 3 Dose Standard	0 of 165 (0%)	0 of 165 (0%)	0 of 165
Males, 2 Dose With Delayed 3rd Dose	0 of 164 (0%)	0 of 164 (0%)	0 of 164

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 16 Apr 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 41276263Bergman H, Henschke N, Arevalo-Rodriguez I, Buckley BS, Crosbie EJ, Davies JC, Dwan K, Golder SP, Loke YK, Probyn K, Petkovic J, Villanueva G, Morrison J. Human papillomavirus (HPV) vaccination for the prevention of cervical cancer and other HPV-related diseases: a network meta-analysis. Cochrane Database Syst Rev. 2025 Nov 24;11(11):CD015364. doi: 10.1002/14651858.CD015364.pub2.
Derived from this study: PubMed 38320488Berenson AB, Panicker G, Unger ER, Rupp RE, Kuo YF. Immunogenicity of 2 or 3 Doses of 9vHPV Vaccine in U.S. Female Individuals 15 to 26 Years of Age. NEJM Evid. 2024 Feb;3(2):EVIDoa2300194. doi: 10.1056/EVIDoa2300194. Epub 2024 Jan 23.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Abbey B Berenson, MD, PhD principal investigator

University of Texas

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 16 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 17 Feb 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Short-term Human Papillomavirus (HPV) Type-specific Antibody Response for Type HPV-6 (time frame: Month 7). The study lists 18 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03943875, which also lists 2 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Apr 2026.