CompletedNCT04142086VYF01Updated Sep 22, 2025

Dose-ranging Study of an Investigational Yellow Fever Candidate Vaccine in Adults

A Phase 1 interventional study of Yellow fever vaccine (produced on serum-free Vero cells), Dosage 1 vYF vaccine and Yellow fever vaccine (produced on serum-free Vero cells), Dosage 2 vYF vaccine in Yellow Fever (Healthy Volunteers), sponsored by Sanofi Pasteur, a Sanofi Company. Completed at 1 site in United States. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-09-22.

Sponsored by Sanofi Pasteur, a Sanofi Company · Phase 1, Interventional, and Prevention

From the registry’s dates

Primary completion was Jun 2021, 5 years 3 months ago, and no results have been posted to the registry.

Phase: Phase 1
Study type: Interventional
Enrollment: 73
Allocation: Randomized
Ages: 18 Years to 60 Years
Sex: All

Study summary

The primary objectives of the study are:

To describe the safety profile of each of the 3 dosages of vYF and of YF-VAX® within the 28 days post-vaccination and up to the 6 months (Day 180) post-vaccination visit
To describe the antibody responses elicited by each of the 3 dosages of vYF and by YF-VAX on Day 0 pre-vaccination and then on Day 10, Day 14, Day 28 and 6 months (Day 180) post-vaccination overall and by baseline flavivirus serostatus
To quantify the detectable yellow fever (YF) vaccinal viremia in each vaccine groups (vYF and YF-VAX) in a subset of subjects on Day 0 visit, Day 1 visit, Day 3 visit, Day 5 visit, Day 7 visit, Day 10 visit, and Day 14 visit.

Read the detailed description

Study duration per participant is approximately 6 months.

Conditions studied

Yellow Fever (Healthy Volunteers)

Browse trials for

Yellow Fever 60

In context

Yellow Fever

60 studies on the registry are indexed under Yellow Fever; 12 are open to participants now.

This study's enrollment of 73 is below the median of 110 across 48 interventional studies indexed under Yellow Fever.

Browse Yellow Fever studies →

Lead sponsor

Sanofi Pasteur, a Sanofi Company is the lead sponsor of 366 studies on the registry; 4 are open to participants now.

Of its 94 completed or terminated interventional studies of FDA-regulated products, 73 (78%) have results posted.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 18 Years to 60 Years
Sexes eligible: All
Accepts healthy volunteers: Yes

Inclusion criteria

Aged 18 years up to 60 years on the day of inclusion
Able to read and understand the Informed Consent Form which has been signed and dated
Able to attend all scheduled visits and to comply with all trial procedures

Exclusion criteria

Exclusion criteria:

Participant is pregnant, or lactating, or of childbearing potential and not using an effective method of contraception or abstinence from at least 4 weeks prior to vaccination until at least 4 weeks after vaccination. To be considered of non-childbearing potential, a female must be pre-menarche , or post-menopausal for at least 1 year, or surgically sterile
Participation at the time of study enrollment (or in the 4 weeks preceding the trial vaccination) or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure
Receipt of any vaccine in the 4 weeks preceding the trial vaccination or planned receipt of any vaccine in the 4 weeks following the trial vaccination
Previous vaccination against a flavivirus disease including YF with either the trial vaccine or another vaccine
Receipt of immune globulins, blood, or blood-derived products in the past 6 months
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 trial 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 of family history of thymic pathology (thymoma, thymectomy, or myasthenia)
Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily
Current alcohol abuse or drug addiction
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
Identified as an Investigator or employee of the Investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (ie, parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study
Planned travel in a YF endemic country within 6 months of investigational or control vaccine administration

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Study design

Phase: Phase 1
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel assignment
Masking: Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment: 73 participants (actual)

Study arms

Experimental
Group 1
1 injection of vYF vaccine Dosage 1
Biological: Yellow fever vaccine (produced on serum-free Vero cells), Dosage 1 vYF vaccine
Experimental
Group 2
1 injection of vYF vaccine Dosage 2
Biological: Yellow fever vaccine (produced on serum-free Vero cells), Dosage 2 vYF vaccine
Experimental
Group 3
1 injection of vYF vaccine Dosage 3
Biological: Yellow fever vaccine (produced on serum-free Vero cells), Dosage 3 vYF vaccine
Active comparator
Group 4
1 injection of YF-VAX
Biological: Yellow fever vaccine

Interventions

BiologicalYellow fever vaccine (produced on serum-free Vero cells), Dosage 1 vYF vaccine
Pharmaceutical form: Powder and diluent for suspension for injection Route of administration: Subcutaneous
BiologicalYellow fever vaccine (produced on serum-free Vero cells), Dosage 2 vYF vaccine
Pharmaceutical form: Powder and diluent for suspension for injection Route of administration: Subcutaneous
BiologicalYellow fever vaccine (produced on serum-free Vero cells), Dosage 3 vYF vaccine
Pharmaceutical form: Powder and diluent for suspension for injection Route of administration: Subcutaneous
BiologicalYellow fever vaccine
Pharmaceutical form: Powder and diluent for suspension for injection Route of administration: Subcutaneous
Also known as: YF-VAX

What researchers measure

Primary outcomes

Number of participants with immediate adverse events
Immediate adverse events are any unsolicited systemic adverse events reported in the 30 minutes after vaccination
Time frame: Within 30 minutes after vaccination
Number of participants with solicited injection site reactions
Solicited injection site reactions include injection site pain, erythema and swelling
Time frame: Within 7 days after vaccination
Number of participants with solicited systemic reactions
Solicited systemic reactions include fever, headache, malaise, and myalgia
Time frame: Within 14 days after vaccination
Number of participants with unsolicited adverse events
Unsolicited (spontaneously reported) adverse events not fulfilling criteria for solicited adverse reactions
Time frame: Within 28 days after vaccination
Number of participants with Grade 3 fever
Grade 3 fever is defined as temperature ≥ 102.1°F
Time frame: Within 28 days after vaccination
Number of participants with serious adverse events
Serious adverse events are collected throughout the study
Time frame: From Day 0 to Day 180
Number of participants with hematology and biochemistry out-of-range test results
Hematology and biochemistry values that are out-of-range are assessed
Time frame: From Day 0 to Day 14
Number of participants with YF and flavivirus viremia and out-of-normal-range biological test results in the event of severe fever, or suspicion of neurotropic disease or acute viscerotropic diseases
Investigators are provided with guidelines for recognition and assessment of potential viscerotropic and neurotropic events
Time frame: Within 28 days after vaccination
Number of participants with seroconversion to YF virus
Seroconversion is defined as a fourfold increase in neutralizing antibody titers as compared to pre-vaccination value. Seroconversion is assessed from Day 0 (pre-vaccination) to Day 10, Day 14 and Day 28.
Time frame: From Day 0 to Day 28
Number of participants with neutralizing antibody titers against YF virus above pre-defined threshold
Pre-defined threshold of 10 1/dilution
Time frame: From Day 0 to Day 180
Geometric mean titers of neutralizing antibodies against YF virus
Geometric mean titer ratio Day 10/Day 0, Day 14/Day 0, Day 28/Day 0 and Day 180/Day 0
Time frame: From Day 0 to Day 180
Number of participants with YF vaccinal viremia
Vaccinal viremia is measured by YF specific quantitative reverse transcription polymerase chain reaction (RT-PCR) assay in samples collected on Day 0, Day 1, Day 3, Day 5, Day 7, Day 10, and Day 14.
Time frame: From Day 0 to Day 14
Level of YF vaccinal viremia
Vaccinal viremia is measured by YF specific quantitative RT-PCR assay in samples collected on Day 0, Day 1, Day 3, Day 5, Day 7, Day 10, and Day 14.
Time frame: From Day 0 to Day 14

Study locations

1 site

Investigational Site Number 8400001
Silver Spring, Maryland 20910, United States

References and documents

Publications

Pagnon A, Carre C, Aguirre M, Chautard E, Gimenez S, Raynal F, Feroldi E, Scott P, Modjarrad K, Vangelisti M, Mantel N. Next generation yellow fever vaccine induces an equivalent immune and transcriptomic profile to the current vaccine: observations from a phase I randomised clinical trial. EBioMedicine. 2024 Oct;108:105332. doi: 10.1016/j.ebiom.2024.105332. Epub 2024 Sep 17. PubMed 39293214 ↗

Individual participant data

Plan to share: Yes — Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Sep 22, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT04142086
Lead sponsor: Sanofi Pasteur, a Sanofi Company
Responsible party: Sponsor
First posted: Oct 29, 2019
Start date: Jan 15, 2020
Primary completion: Jun 24, 2021
Completion: Jun 24, 2021
Last update: Sep 22, 2025

Study contacts

Clinical Sciences & Operations

study director · Sanofi Pasteur, a Sanofi Company

Oversight

Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No

View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Sep 2025. You cannot join it, but the record below documents what was studied.

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