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

NCT07103148 | Recruiting Phase 3 DMC FDA Drug

• 2 other identifiers: VYF04U1111-1300-4387
• Study Type: interventional
• Target: 2,440
• Locations: 3 countries
• Sites: 13

Brief 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.

Conditions

Yellow Fever Immunization

Keywords

Yellow fever

Outcome Measures

Primary Outcomes (4)

• Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the Stamaril in YF-naive participants (9-24 months)

  Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value

  At Day 29, 28 days post-vaccination (on Day 01) with vYF or Stamaril

• Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the YF-VAX in YF-naive participants (9-24 months)

  Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value

  At Day 29, 28 days post-vaccination (on Day 01) with vYF or YF-VAX

• Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the Stamaril in YF-naive participants (2-5 years)

  Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value

  At Day 29, 28 days post-vaccination (on Day 01) with vYF or Stamaril

• Percentage of participants with seroconversion to YF virus after 1 dose of vYF compared to seroconversion after 1 dose of the YF-VAX in YF-naive participants (2-5 years)

  Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in NAb titers as compared to the pre-vaccination value

  At Day 29, 28 days post-vaccination (on Day 01) with vYF or YF-VAX

Secondary Outcomes (29)

• Percentage of participants, by age group, with seroconversion to YF virus in all investigational vaccine groups before (Day 01) and after investigational vaccine administration at various timepoints

  At Day 01 and at Day 11 (in a subset), Day 15 (in a subset), Day 29, Month 6, and yearly from Year 1 to Year 3

• Percentage of participants, by age group, with seroprotection to YF virus in all investigational vaccine groups before (Day 01) and after investigational vaccine administration at various timepoints

  At Day 01 and at Day 11 (in a subset), Day 15 (in a subset), Day 29, Month 6, and yearly from Year 1 to Year 3

• Geometric Mean Titers (GMTs) of neutralizing antibodies against YF virus in all investigational vaccine groups, by age group, before (Day 01) and after investigational vaccine administration at various timepoints

  At Day 01 and at Day 11 (in a subset), Day 15 (in a subset), Day 29, Month 6, and yearly from Year 1 to Year 3

• Geometric Mean Titers Ratio (GMTRs) of neutralizing antibodies against YF virus in all investigational vaccine groups, by age group, before (Day 01) and after investigational vaccine administration at various timepoints

  GMTRs Day 11/Day 01 (subset only), Day 15/ D01 (subset only), Day 29/Day 01, Month 6/Day 01, Year 1/Month 6, Year 2/Year 1, Year 3/Year 2

• Percentage of participants with seroconversion to YF virus in all investigational vaccine groups 28 days after the co-administration of vYF with measlescontaining vaccine in the MMR group and at successive timepoints

  28 days after the coadministration of MMR with vYF At Month 6 and yearly from Year 1 to Year 3

Study Arms (7)

Group 1 (9-24 months)

EXPERIMENTAL

Primary vaccination phase: 1 injection of vYF vaccine at Day 1 Booster phase: 1 injection of vYF vaccine at Year 3 (in a subset)

Biological: Yellow fever vaccine (live)

Group 2 (9-24 months)

ACTIVE COMPARATOR

Primary vaccination phase: 1 injection of Stamaril vaccine at Day 1 Booster phase: 1 injection of Stamaril vaccine at Year 3 (in a subset)

Biological: Yellow fever vaccine (live)

Group 3 (9-24 months)

ACTIVE COMPARATOR

Primary vaccination phase: 1 injection of YF-VAX vaccine at Day 1 Booster phase: 1 injection of YF-VAX vaccine at Year 3 (in a subset)

Biological: Yellow fever vaccine (live)

Group 4 (2-5 years)

EXPERIMENTAL

Primary vaccination phase: 1 injection of vYF vaccine at Day 1

Biological: Yellow fever vaccine (live)

Group 5 (2-5 years)

ACTIVE COMPARATOR

Primary vaccination phase: 1 injection of Stamaril vaccine at Day 1

Biological: Yellow fever vaccine (live)

Group 6 (2-5 years)

ACTIVE COMPARATOR

Primary vaccination phase: 1 injection of YF-VAX vaccine at Day 1

Biological: Yellow fever vaccine (live)

Group 7 (approximately 11-15 months)

EXPERIMENTAL

Primary vaccination phase: 1 injection of MMR vaccine at Day 1 in a cohort of 11 to 15 months of age vaccinated with vYF

Biological: Yellow fever vaccine (live); Biological: Measles, combinations with mumps and rubella, live attenuated

Interventions

Yellow fever vaccine (live) BIOLOGICAL

Powder and diluent for suspension for injection Subcutaneous

Also known as: vYF vaccine

Group 1 (9-24 months); Group 4 (2-5 years); Group 7 (approximately 11-15 months)

Measles, combinations with mumps and rubella, live attenuated BIOLOGICAL

Powder, lyophilized, for suspension for reconstitution Subcutaneous or intermuscular

Also known as: MMR II vaccine

Group 7 (approximately 11-15 months)

Eligibility Criteria

• Age: 9 Months - 5 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• \* "9 months to 5 years" means from the day of the 9th month after birth to the day before the 6th year birthday
• \* "11 to 15 months" means from the day of the 11th month after birth to the day before the 16th month birthday
• Participants who are healthy as determined by medical evaluation including medical history and physical examination
• For infants\*, born after a gestation period of 27 through 36 weeks and medically stable as assessed by the investigator, based on the following definition: "Medically stable" refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study intervention
• \* Infants aged 9 months to 11 months up to the day before the 12th month birthday
• Participant and parent/LAR are able to attend all scheduled visits and to comply with all study procedures
• ICF has been signed and dated by the parent(s) or other LAR (and by an independent witness if required by local regulations)

You may not qualify if:

• Participants are excluded from the study if any of the following criteria apply:
• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy irradiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months)
• Known history of FV infection
• Known systemic hypersensitivity to any of the study intervention components, eggs or history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances
• Moderate or severe acute illness/infection (according to Investigator judgment) or febrile illness (temperature ≥ 38.0°C \[≥ 100.4°F\]) on the day of study intervention administration. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
• Chronic illness\* that, in the opinion of the Investigator, is at a stage where it might interfere with study conduct or completion , including malignancy, such as leukemia, or lymphoma
• \*Chronic illness may include, but is not limited to, cardiac disorders, renal disorders, auto-immune disorders, diabetes, psychiatric disorders or chronic infection
• History of central nervous system disorder or disease, including seizures and febrile seizures
• Receipt of any vaccine in the 4 weeks preceding the study intervention administration or planned receipt of any vaccine in the 4 weeks following the study intervention administration. Vaccine to be administered as part of the National Immunization Schedule will be postponed after the D29 visit
• Previous vaccination against a FV disease at any time including YF with an investigational or marketed vaccine
• Receipt of immune globulins, blood or blood-derived products in the past 6 months
• Administration of any anti-viral within 2 months preceding the study intervention administration and up to the 6 weeks following the study intervention administration
• For participants enrolled in the MMR co-administration group: previous vaccination against measles, measles/mumps/rubella
• For participants enrolled in the MMR co-administration group: history of measles, mumps, rubella confirmed either clinically, serologically, or microbiologically
• Known history or laboratory evidence of HIV infection

Sponsors & Collaborators

• Sanofi: lead

Study Sites (13)

Investigational Site Number : 3400001

San Pedro Sula, 21104, Honduras

RECRUITING

Investigational Site Number : 3400005

San Pedro Sula, Cortes, 21104, Honduras

RECRUITING

Investigational Site Number : 3400002

Tegucigalpa, 11101, Honduras

RECRUITING

Investigational Site Number : 3400003

Tegucigalpa, 11101, Honduras

RECRUITING

Investigational Site Number : 3400007

Tegucigalpa, 11101, Honduras

RECRUITING

Investigational Site Number : 4840007

Torreón, Coahuila, 27000, Mexico

RECRUITING

Investigational Site Number : 4840013

Cuernavaca, Morelos, 62290, Mexico

RECRUITING

Investigational Site Number : 4840015

Tizimín, Yucatán, 97700, Mexico

RECRUITING

Investigational Site Number : 4840009

Chihuahua City, 31000, Mexico

RECRUITING

Investigational Site Number : 4840005

Ecatepec de Morelos, 55075, Mexico

RECRUITING

Investigational Site Number : 5910001

Panama City, 10662, Panama

RECRUITING

Investigational Site Number : 5910002

Panama City, 10662, Panama

RECRUITING

Investigational Site Number : 5910003

Panama City, 10662, Panama

RECRUITING

Related Links

• VYF04 Plain Language Results Summary

MeSH Terms

Conditions

Yellow Fever

Interventions

Yellow Fever Vaccine

Condition Hierarchy (Ancestors)

Mosquito-Borne Diseases; Vector Borne Diseases; Infections; Arbovirus Infections; Virus Diseases; Flavivirus Infections; Flaviviridae Infections; RNA Virus Infections; Hemorrhagic Fevers, Viral

Intervention Hierarchy (Ancestors)

Viral Vaccines; Vaccines; Biological Products; Complex Mixtures

Central Study Contacts

Trial Transparency email recommended (Toll free for US & Canada)

CONTACT

800-633-1610; Contact-US@sanofi.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: * Sponsor, Investigators, Study staff who conduct the safety assessment and the participant' parent(s) / LAR(s) will not know which study intervention is administered. * Only the study staff who prepare and administer the study interventions and are not involved with the safety evaluation will know which study intervention is administered.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 7, 2025
• First Posted: August 5, 2025
• Study Start: July 11, 2025
• Primary Completion (Estimated): August 8, 2026
• Study Completion (Estimated): March 4, 2030
• Last Updated: May 6, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will share

Locations

PA (3); ME (5); HO (5)