NCT07314307

Vaccine Effectiveness of One Dose of the Nonavalent Human Papillomavirus (HPV) Vaccine Among Young-adult Women in Sweden Among Women Participating in a Clinical Trial of Concomitant HPV Vaccination and Screening

• Status: Active Not Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 150,000 (estimated)
• Sponsor: Karolinska Institutet · Academic / Other
• Sex: Female
• Age: 22 Years – 31 Years
• Healthy volunteers: Accepted

Summary

This study aims to evaluate the vaccine effectiveness of 1 dose the nonavalent human papillomavirus (HPV) vaccine against HPV16, 18, 31, 33, 45, 52, and 58 infection among young adult women in Sweden participating in a nationwide HPV elimination trial.

Detailed description

HPV vaccination is the 1st pillar in the World Health Organization's (WHO) strategy to eliminate cervical cancer as public health problem, defined as an incidence of under 4 per 100,000 women-years globally. Licensed prophylactic HPV vaccines are highly efficacious in preventing HPV infection and associated cancers. At the time of licensure, the first-generation vaccines were licensed with a 3-dose schedule, and subsequently with a 2-dose schedule for women aged 15 and under. However, based on promising findings from observational studies of high vaccine effectiveness after only one dose, and subsequent clinical trials, the Strategic Advisory Group of Experts on Immunization (SAGE) recommended an off-label HPV vaccination regimen of one dose for girls and women from the age of 9 to 20 years-old. However, for women aged 21 or older a 2-dose schedule is still recommended by the WHO. This nationwide trial of concomitant HPV vaccination among women aged 22 to 30-years-old in Sweden is a unique opportunity to evaluate the vaccine effectiveness of one dose of HPV vaccination among women over the age of 20 years old. Studies on the efficacy and effectiveness of one dose among women over the age of 20 years old are scarce and of varying quality. The findings of this study will be crucial to inform public health decision makers and in contributing to the evidence base for assessing if the 2-dose schedule recommendation among women over 20-years-old is still warranted.

Conditions

• Incident HPV16, 18, 31, 33, 45, 52 or 58 Infection

Interventions

Type	Name	Description
BIOLOGICAL	Gardasil 9 2 dose regimen	Women ages 22-26 will be offered concomitant vaccination (1 dose of Gardasil9) and HPV screening. A second dose of Gardasil9 will be administered 3 years later.

Timeline

• Start date: 2021-05-03
• Primary completion: 2027-12-31
• Completion: 2028-12-31
• First posted: 2026-01-02
• Last updated: 2026-01-02

Locations

1 site across 1 country: Sweden