Comparing immune responses of 2 vs 3 doses of HPV vaccine in women aged 27-45

Comparison of the Immune Response After Administration of 2 vs. 3 Doses of the FDA-approved 9-Valent HPV Vaccine Among Women 27-45 Years of Age

Phase 4 Interventional The University of Texas Medical Branch, Galveston · NCT05672927

This study is testing whether getting 2 doses of the HPV vaccine is just as effective at boosting the immune response as getting 3 doses for women aged 27-45.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment618 (estimated)
Ages27 Years to 45 Years
SexFemale
SponsorThe University of Texas Medical Branch, Galveston Academic / other
Drugs / interventionsrituximab, chemotherapy, radiation
Locations1 site (Galveston, Texas)
Trial IDNCT05672927 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to compare the immune response elicited by a 2-dose versus a 3-dose series of the 9-valent HPV vaccine in females aged 27-45. Participants will be randomly assigned to receive either 2 doses at 0 and 6 months or 3 doses at 0, 2, and 6 months. Blood samples will be collected at various intervals over 12 months to assess immune response. After the final blood draw, those in the 2-dose group will be offered a 3rd dose. The study seeks to determine if the 2-dose regimen can provide an immune response comparable to the standard 3-dose regimen.

Who should consider this trial

Good fit: Ideal candidates are females aged 27-45 who have not previously received any doses of the HPV vaccine.

Not a fit: Patients who are currently pregnant or have received prior doses of the HPV vaccine will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could simplify HPV vaccination schedules and improve accessibility for women in the target age group.

How similar studies have performed: Previous studies have shown promising results with alternate dosing regimens for vaccines, suggesting potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion criteria:

1. Females 27-45 years old.
2. Ability to give informed consent.
3. Has not received any prior doses of the HPV vaccine. This will be verified by the person and state registry (Immtrac), as well as the person's electronic medical record.
4. Reliable telephone access for the duration of the project.
5. Can read and speak in either English or Spanish.
6. Identified source of funding for vaccine such as Medicaid, private health insurance, Texas Healthy Women program, etc.
7. Reports consistent use of reliable birth control and plans to continue its use through study month 13.

Exclusion criteria:

1. Currently pregnant or plans to become pregnant or donate eggs in the next 13 months. Any subjects with positive pregnancy tests at the initial visit will be disqualified from the study and advised to seek prenatal care.
2. Has an immunodeficiency or autoimmune disease such as HIV infection, lymphoma, leukemia, lupus, rheumatoid arthritis, inflammatory bowel disease, or other autoimmune condition.
3. Currently receiving treatment or medication that can suppress immune function including radiation therapy, chemotherapy, cyclosporin, leflunomide (Arava), TNF-α antagonists, monoclonal antibody therapies (including rituximab \[Rituxan\]), intravenous gamma globulin (IVIG), antilymphocyte sera, other therapy known to interfere with the immune response, or systemic corticosteroids (by mouth or intramuscular injection). Those using or have used steroids that are inhaled, placed in the eye, applied on the skin, or injected into the joint/soft tissue will be considered eligible for the study.
4. History of splenectomy
5. Known allergies to any vaccine components, including aluminum, yeast or Benzonase.
6. Febrile at ≥100°F in the 24 hours prior to vaccination. The patients may be rescheduled for a later date.
7. History of thrombocytopenia or any coagulation disorder that would contraindicate intramuscular injections.
8. History of \>10 sexual partners in their lifetime at time of enrollment
9. Plans to move out of the Galveston/Houston area in the 13 months following study entry.

Where this trial is running

Galveston, Texas

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions ImmunizationHPV InfectionHuman PapillomavirusHPV vaccinationGardasil 9Noninferiority trial
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.