Persistence of Immune Response Six Years After One Dose of 9vHPV Vaccine Among Male and Female Students

Since the 2019-2020 school year, the province of Quebec (Canada) has been administering one dose of nonavalent (9vHPV) vaccine to students of all genders in Grade 4 of elementary school through the school-based program. Little data on the immunogenicity (antibody production) and long-term efficacy of a single dose of the vaccine are available, particularly in boys. The primary objective of this study is to assess the persistence of HPV antibodies six years after the administration of a single dose of the 9vHPV vaccine to students aged 9 to 11 years in Grade 4 in 2019-2020. The study will be conducted at the CHU de Québec-Université Laval research center. Recruitment is conducted through school service centers in the Quebec City region. Youth who received only a single dose of the 9vHPV vaccine at the ages of 9-11 in 2019-2020 will be eligible to participate. Approximately 300 youth will take part in this study: 150 girls and 150 boys. Participants will have to answer few questions about their health to ensure their eligibility for the study. For eligible participants consenting to participate a 10 ml (\<1 tablespoon) blood sample will be taken.

NCT Number	NCT07156084
Lead Sponsor	Canadian Immunization Research Network
Conditions	HPV Vaccine
Enrollment	300 participants
Start Date	2025-09-23
Primary Completion	2026-02 (estimated)
Study Completion	2026-02 (estimated)
Updated on ClinicalTrials.gov	2025-09-29