NCT07103148

A Phase III Control Study of the Safety and Immunogenicity of vYF in Pediatric Population

A Parallel Group, Phase III Randomized, Modified Double-blind, Active Controlled Study to Investigate the Immunogenicity and Safety of vYF Compared to Licensed YF Vaccines in Pediatric Population Aged 9 Months to 5 Years of Age

• Status: Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 2,440 (estimated)
• Sponsor: Sanofi · Industry
• Sex: All
• Age: 9 Months – 5 Years
• Healthy volunteers: Accepted

Summary

The purpose of this study is to determine whether vYF (investigational vaccine) is safe and can help the body to develop antibodies (immunogenicity) compared with Stamaril vaccine and YF-VAX vaccine (both licensed vaccines) and when they are co-administered with Measles Mumps Rubella (MMR) vaccines in infants aged 11-15 months. Number of Participants: A total of 2440 participants is planned to be enrolled in VYF04 study. Study Arms and Duration: Eligible participants will be randomized in 2 independent groups (9-24 months, 2-5 years) to receive 1 dose of either vYF or Stamaril or YF-VAX in a 2:1:1 ratio within each age group. An additional group with participants of 11-15 months of age will also receive at the same vaccination visit vYF and a single dose of MMR vaccine. For the 2nd step (YF booster vaccine administration in a subset), at the Year (Y) 3 visit, a subset of 120 participants of the 9-24 months of age group who did receive a YF vaccine on Day(D) 01 will be invited to join a booster dose assessment (booster dose administered after the Y3 visit blood sample has been taken). Participants aged 11 to 15 months at the time of the concomitant administration of vYF and MMR will not be eligible for receiving a booster dose. The duration of each participation will be approximately 3 years for all participants (including participants co-administered on D01 with vYF and MMR), and 6 more months post-booster dose administration for the participants enrolled in the booster subset.

Detailed description

The duration of each participant's participation will be up to approximately 3 years (not including booster phase in a subset) The Phase III VYF04 is the first study to be carried out with the investigational vYF in pediatric populations.

Conditions

• Yellow Fever Immunization

Interventions

Type	Name	Description
BIOLOGICAL	Yellow fever vaccine (live)	Powder and diluent for suspension for injection Subcutaneous
BIOLOGICAL	Yellow fever vaccine (live)	Powder and diluent for suspension for injection Subcutaneous
BIOLOGICAL	Yellow fever vaccine (live)	Powder and diluent for suspension for injection Subcutaneous
BIOLOGICAL	Measles, combinations with mumps and rubella, live attenuated	Powder, lyophilized, for suspension for reconstitution Subcutaneous or intermuscular

Timeline

• Start date: 2025-07-11
• Primary completion: 2026-08-08
• Completion: 2030-03-04
• First posted: 2025-08-05
• Last updated: 2026-03-10

Locations

9 sites across 2 countries: Honduras, Mexico

Regulatory

• FDA-regulated drug study