NCT04688476Active, not recruiting
An Extended Follow-Up Study of the HPV Vaccine Delayed Booster Trial
Source: ClinicalTrials.gov · Last updated 9 Oct 2026
Brief summary (registry, in English)
This is an extended follow-up study to follow-up study participants who received 1 booster dose of Gardasil 9 in the "HPV vaccine delayed booster trial." This was a prospective, single-arm, open-label, non-randomized, phase IIa trial among 9-11 year-old girls and boys to determine the immunogenicity after a single dose of the nonavalent HPV vaccine (Gardasil 9) over 24 months, with a delayed booster dose at 24 months and an optional booster at 30 months after the first dose. Participants provided blood specimens at 6, 12, 18, 24, and 30 months after the first dose. Serologic geometric mean titers (GMT) of the nine vaccine types (HPV 16/18/ 6/11/31/33/45/52/58) were measured at each time point. One hundred and thirty-three (133) participants received one booster dose at month 24 and elected not to receive the second booster at month 30. For this follow-up study, we anticipate that we will be able to accrue 120 participants from the original study who received just one booster dose. Participants who received one booster dose of Gardasil 9 will be contacted to return to the clinic to provide blood specimens at 48 (±3), 60 (±3), and 72 (±3) months after the priming dose. Serologic geometric mean titers (GMT) of the nine vaccine types (HPV 16/18/ 6/11/31/33/45/52/58) will be measured at each time point.
- Status (registry)
- Active, not recruiting
- Study type
- Observational
- Enrollment
- 113 (actual)
- First submitted
- 17 Dec 2020
- Start date
- Nov 2020
- Primary completion date
- Sept 2025
- Lead sponsor
- University of Arizona
- Diseases
- Childhood cancers
- NCT number
- NCT04688476
What you commit to
- Study type: Observational
- Participants enrolled: 113
- From Nov 2020 to the primary completion date, Sept 2025
- 2 sites in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- \- Has received any HPV vaccine dose from an external source at any point during or after participation in the HPV vaccine delayed booster trial.
Who the study is looking for
- Study participants who received one booster dose of Gardasil 9 at month 24 and elected not to receive the second booster at month 30 in the original "HPV vaccine delayed booster trial"
- Ability to understand and the willingness to sign a written informed consent document by the legal representative(s) of the participant.
- Ability to understand and the willingness to sign a written assent document by the participant.
Sex: All · Accepts healthy volunteers
Sites (2)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| University of California, Los Angeles Coordinator of this site? Confirm its status | Los Angeles | United States | Unknown status |
| University of Arizona Coordinator of this site? Confirm its status | Tucson | United States | Unknown status |
This page is information, not medical advice. Discuss any trial with your doctor.