The HPV 9-10 Trial: Early Initiation of HPV Vaccination

April 17, 2026 updated by: University of Colorado, Denver
Every year, thousands of Americans die from cancers related to human papillomavirus (HPV). The vast majority of those deaths could be prevented with a safe and effective vaccine, yet many parents choose not have their children vaccinated when it is recommended at age 11 or 12. In this study, we will examine in a randomized trial whether earlier initiation of the vaccine at age 9-10 years will result in less parental refusal and higher rates of full vaccination at younger ages, before early sexual activity begins.

Study Overview

Detailed Description

The burden of Human Papillomavirus (HPV)-related disease in the US is substantial. A safe and effective vaccine has been available for >10 years, yet the current rate of completion for the HPV series is only 49% for U.S.13-17 year olds. The Advisory Committee on Immunization Practices (ACIP) recommends routine HPV vaccination at age 11-12 years (yrs), but states that the vaccine "can be given starting at age 9 years." Currently, the majority of pediatricians begin recommending the vaccine at ages 11-12 yrs, however, a recent retrospective study showed that on-time completion rates for HPV vaccine were much higher when the vaccine series was initiated at ages 9-10 compared to ages 11-12 (adjusted odds ratio, 12.8).

HPV vaccine should be given prior to sexual activity which occurs earlier than 13 yrs for many teens. There are compelling reasons to think that earlier initiation of vaccination at ages 9-10 might result in higher rates of acceptance of the vaccine and earlier series completion. First, many parents refuse HPV vaccine because they have concerns that vaccination could result in higher promiscuity in early adolescents if the vaccine is discussed in the context of sexuality. Initiation at 9-10 yrs, when few providers discuss sex, could put the focus squarely on cancer prevention, decreasing vaccine refusal. Second, three vaccines are recommended at the 11-12 yr visit, but many parents/adolescents are unwilling to receive all three at one visit. When one of the vaccines is delayed, it is almost always HPV vaccine. Initiation at 9-10 yrs when no other vaccines are given could result in less deferral of vaccination to mid-adolescence and higher rates of vaccination prior to early sexual activity. Finally, initiation at age 9-10 years has been shown to be feasible and, in an observational study, to result in higher rates of on-time series completion.

Therefore, we plan to test the effectiveness of shifting initiation of HPV vaccine to 9-10 yrs in a randomized pragmatic trial. Our Specific Aims are to: SA 1: Recruit practices in two states (Colorado and California), randomize in a balanced fashion to recommending HPV vaccine at ages 9-10 yrs or 11-12 yrs and provide standardized training to both arms. SA 2: Conduct a trial to assess effectiveness of early initiation on the primary outcome of age at HPV series completion; secondary outcomes will examine HPV series completion by age 13 and age at HPV series initiation. SA 3: Examine the effect of earlier initiation on length of time for HPV vaccine discussions and on parent/provider communication about HPV vaccine via audio-taping of visits, audio-elicitation interviews with parents and structured interviews with providers and clinic staff.

If earlier HPV initiation is successful in promoting higher HPV series completion by 13 yrs, this intervention could be rapidly disseminated and would have the potential to prevent thousands of cases of HPV-related cancers, their attendant morbidity and mortality as well as the costs of screening, diagnosis and treatment for these cancers yearly.

Study Type

Interventional

Enrollment (Estimated)

3100

Phase

  • Not Applicable

Contacts and Locations

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

Study Locations

    • California
      • Los Angeles, California, United States, 90095
        • University of California at Los Angeles
    • Colorado
      • Aurora, Colorado, United States, 80045
        • University of Colorado

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

Ages Eligible for Study

18 years and older (Child)

Accepts Healthy Volunteers

No

Description

Practices:

Inclusion Criteria:

  • Practices in Metro Denver, Colorado and Metro Los Angeles, California (specifically UCLA medical clinics and clinics affiliated with Children's Hospital of Orange County)
  • Practices that have at least 60% of providers agree to participate
  • Practices do not currently recommend HPV at 9-10 years.
  • Practice must have at least 100 eligible patients age 9-13 years

Exclusion Criteria:

  • Practices with less than 100 eligible patients age 9-13 years
  • Practices currently routinely recommend HPV vaccine at 9-10 years.
  • Practices where less than 60% of providers agree to participate in the study.

Patient Eligibility Criteria

  • Patient age 9-13 years
  • Seen at a participating practice in the last 3 years
  • Due for at least 1 dose of HPV vaccine

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: Health Services Research
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Patients attributed to practices recommending HPV at age 9-10 years of age
Patients attributed to practices routinely recommending HPV vaccine starting at 9-10 years of age.
Practices are randomized to receive training on how to recommend HPV vaccine, including both standardized communication strategies and strategies for switching from 11-12 years to 9-10 years including: challenges with 11-12 strategy, long-term immunity, success of other practices and tips to help standardize to age 9-10. Trainings will be a combination of online and in-person or virtual. Annual trainings will be offered and providers will receive Maintenance of Certification credits (MOC) for participating. Providers will routinely recommend HPV starting at age 9 for all patients -- which is already approved for this vaccine but is not routinely recommended at age 9 years.
Active Comparator: Patients attributed to practices recommending HPV at age 11-12 years of age
Patients attributed to practices routinely recommending HPV vaccine starting at 11-12 years of age.
Control practices will receive a training on standardized communication for HPV vaccine including: using strong recommendations, using presumptive recommendation, providing specific phrases to use with parents, answering common questions and, HPV vaccine as a cancer prevention. Annual trainings will be offered and providers will receive professional development credit (MOC).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Age at completion of two dose HPV series
Time Frame: post-intervention assessed in year 5 of study, year 4 of trial
The primary outcome will be age at completion of the two dose HPV series. This is a time-to-event outcome, with the event of interest being vaccine completion. Comparisons between the intervention practices and control practices will be made. Practice electronic health records will be used to assess this outcome.
post-intervention assessed in year 5 of study, year 4 of trial

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
HPV completion by age 13 years
Time Frame: post-intervention assessed in year 5 of study, year 4 of trial
Secondary outcome will be HPV series completion rates by age 13. This will be a binary outcome. Comparisons between the intervention practices and control practices will be made. Practice electronic health records will be used to assess this outcome.
post-intervention assessed in year 5 of study, year 4 of trial
Age at initiation of the HPV series
Time Frame: post-intervention assessed in year 5 of study, year 4 of trial
This is a time-to-event outcome, with the event of interest being vaccine initiation. Comparisons between the intervention practices and control practices will be made. Practice electronic health records will be used to assess this outcome.
post-intervention assessed in year 5 of study, year 4 of trial

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Allison Kempe, MD, MPH, University of Colorado, Denver

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)

December 23, 2019

Primary Completion (Actual)

April 1, 2026

Study Completion (Estimated)

April 1, 2027

Study Registration Dates

First Submitted

January 20, 2021

First Submitted That Met QC Criteria

January 22, 2021

First Posted (Actual)

January 25, 2021

Study Record Updates

Last Update Posted (Actual)

April 22, 2026

Last Update Submitted That Met QC Criteria

April 17, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • 19-3006.cc
  • 1R01CA240649-01A1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The study team guarantees that any and all data collected as part of this project will be released in accordance with standard data sharing policies and procedures to validate research findings if requested. Data will be made available in a timely manner to the broader scientific community, and will be complete, and as accurate as possible. All data released will be de-identified, with no information that could be linked to any study subjects, or participating study practices in order to ensure the confidentiality of all subjects and practices. If necessary, a data use agreement will be established.

IPD Sharing Time Frame

May 2025

IPD Sharing Access Criteria

The study team intends to share study data that may be requested from other research investigators in a data-sharing agreement provided at the individual study's end. The data-sharing agreement will include requirements to protect participants' privacy and data confidentiality. It will prohibit the recipient from transferring the data to other users and will require that the data's security be protected by standard means and be used for research purposes only. The method of distribution will be by request to Dr. Kempe (UCAMC) or Dr. Szilagyi (UCLA), the study PIs. After a requestor completes the data-sharing agreement, we will upload data to a secure File Transfer Protocol (FTP) site with the limited dataset to the requestor, or email the data through our University secured email systems that require users to create an account and sign-in with a username and password in order to receive and download any type of sensitive data.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

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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