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.
Have received a single dose of 9vHPV vaccine at ages 9-11 during the school year 2019-2020;
Not have received any other HPV vaccine doses;
Be able to consent to the study.
Immunosuppressed (at recruitment or when immunized).
Single group
HPV nonavalent vaccine (Gardasil-9)
Biological/VaccineOne dose HPV nonavalent vaccine
Detectable antibodies
Proportion of participants with detectable antibodies
Geometric mean concentrations
Geometric mean concentrations of antibodies
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