Study on an Investigational Yellow Fever Vaccine Compared With YF-VAX in Adults in the USA

NCT04942210 | Active Not Recruiting Phase 2 Results DMC FDA Drug

• 2 other identifiers: VYF02U1111-1261-5612
• Study Type: interventional
• Target: 568
• Locations: 1 country
• Sites: 11

Brief Summary

The primary objective of the study is to demonstrate the non-inferiority of the antibody response in terms of seroconversion rate 28 days after vaccine administration of one dose of yellow fever vaccine (vYF) compared to the antibody response after one dose of the YF-VAX control vaccine in yellow fever naïve participants. The secondary objectives of the study are:

• To describe the immune response to yellow fever in both vaccine groups before and after vYF or YF-VAX administration.
• To describe the safety profile of vYF vaccine in comparison to the safety profile of the control YF-VAX.
• To describe the biosafety profile of vYF in comparison to the biosafety profile of the control YF-VAX.

Conditions

Yellow Fever; Healthy Volunteers

Outcome Measures

Primary Outcomes (1)

• Percentage of Yellow Fever (YF)-Naive Participants Who Achieved Seroconversion 28 Days Post Dose 1

  Seroconversion was defined as a 4-fold increase in Nab titers as compared to the pre-vaccination value. YF-naive participants (or negative) at baseline corresponded to participants with no detectable YF antibody (Ab) titers before vaccination. The YF NAb titers were determined using a validated live virus microneutralization (MN) assay. Percentages are rounded off to the tenth decimal place.

  28 days post dose 1 (Day 29)

Secondary Outcomes (13)

• Percentage of Participants Who Achieved Seroconversion

  Days 1, 11, 29, Month 6, Years 1 and 2

• Percentage of Participants Who Achieved Seroprotection

  Days 1, 11, 29, Month 6, Years 1 and 2

• Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus

  Days 1, 11, 29, Month 6, Years 1 and 2

• Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus

  Days 1, 11, 29, Month 6, Years 1 and 2

• Number of Participants With Unsolicited Systemic Adverse Events (AEs)

  Up to 30 minutes post vaccination on Day 1

Study Arms (2)

vYF

EXPERIMENTAL

1 injection of vYF at Day 1

Biological: Yellow fever vaccine (produced on serum-free Vero cells)

YF-VAX

ACTIVE COMPARATOR

1 injection of YF-VAX at Day 1

Biological: Yellow fever vaccine

Interventions

Yellow fever vaccine (produced on serum-free Vero cells) BIOLOGICAL

Powder and diluent for suspension for injection Subcutaneous injection

vYF

Yellow fever vaccine BIOLOGICAL

Powder and diluent for suspension for injection Subcutaneous injection

Also known as: YF-VAX

YF-VAX

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:
• Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be postmenopausal for at least 1 year, or surgically sterile.
• OR Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to vaccination until at least 4 weeks after vaccination. A participant of childbearing potential must have a negative highly sensitive pregnancy test (urine or serum as required by local regulation) before any dose of study intervention on Day 1 and will be repeated on Day 29 to confirm the participant is still not pregnant within the 28 days of vaccine administration.
• Informed consent form has been signed and dated.
• Able to attend all scheduled visits and to comply with all study procedures.

You may not qualify if:

• Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy, or radiation 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 flavivirus infection.
• Known systemic hypersensitivity to any of the vaccine components, eggs, or history of a life-threatening reaction to the vaccines used in the study or to a vaccine containing any of the same substances.
• Known history or laboratory evidence of human immunodeficiency virus infection.
• Known history of hepatitis B or hepatitis C seropositivity
• Personal or family history of thymic pathology (thymoma, thymectomy, or myasthenia).
• Chronic illness that, in the opinion of the Investigator, is at a stage where it might interfere with trial conduct or completion, including malignancy, such as leukemia, or lymphoma.
• Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (temperature ≥ 100.4°F). A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
• Administration of any anti-viral within 2 months preceding the vaccination and up to the 6 weeks following the vaccination
• Receipt of any vaccine in the 4 weeks preceding the study vaccination or planned receipt of any vaccine in the 4 weeks following the study vaccination except for influenza vaccination, which may be received at least 2 weeks before study vaccines. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines.
• Previous vaccination against a flavivirus disease at any time including YF with either the study vaccine or another vaccine.
• Receipt of immune globulins, blood, or blood-derived products in the past 6 months.
• Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the first year of the 5-year follow-up in another clinical study investigating a vaccine, drug, medical device, or medical procedure. Enrollment in another study after the first year is permitted (starting the first day of Year 2, and onwards), assuming it does not exclude participation in this study
• Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily.
• Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion.

Sponsors & Collaborators

• Sanofi Pasteur, a Sanofi Company: lead

Study Sites (11)

Emory University Decatur- Site Number : 8400005

Decatur, Georgia, 30030, United States

Location

Velocity Clinical Research- New Orleans Site Number : 8400008

New Orleans, Louisiana, 70119, United States

Location

Johns Hopkins Bloomberg School of Public Health (JHSPH)- Site Number : 8400004

Baltimore, Maryland, 21205, United States

Location

Harvard University Medical School- Site Number : 8400002

Boston, Massachusetts, 02115, United States

Location

Saint Louis University- Site Number : 8400003

St Louis, Missouri, 63104, United States

Location

Meridian Clinical Research- Site Number : 8400009

Omaha, Nebraska, 681134, United States

Location

SUNY Upstate Medical University Global Health Institute Site Number : 8400006

East Syracuse, New York, 13057, United States

Location

New York University Langone Medical Center Site Number : 8400013

New York, New York, 10016, United States

Location

Rochester Clinical Research, Inc.- Site Number : 8400010

Rochester, New York, 14609, United States

Location

Velocity Clinical Research - Providence Site Number : 8400015

East Greenwich, Rhode Island, 02818, United States

Location

J Lewis Research Inc- Site Number : 8400012

Salt Lake City, Utah, 84109, United States

Location

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

Results Point of Contact

• Title: Trial Transparency Team
• Organization: Sanofi Pasteur

Contact-US@sanofi.com

800-633-1610 ext: 6#

Study Officials

• Clinical Sciences & Operations

  Sanofi Pasteur, a Sanofi Company

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: The study will be performed in a modified double-blind fashion: Investigators, Sponsor, and study staff who conduct the safety assessment and the participant will not know which vaccine is administered.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 25, 2021
• First Posted: June 28, 2021
• Study Start: July 1, 2021
• Primary Completion: June 24, 2022
• Study Completion (Estimated): June 29, 2027
• Last Updated: June 18, 2025
• Results First Posted: June 18, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will share

Locations

US (11)