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Yellow FeverPhase 3NCT07222059

Phase 3 Single Arm, Open Study on vYF in Adults

A Phase 3 study testing Yellow fever vaccine (live) in people with Yellow Fever, run by Sanofi Pasteur, a Sanofi Company at 4 sites in Japan.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The purpose of this study is to assess the safety and immunogenicity of vYF in adults aged 18 years and over in Japan. Study details include: The study duration will be up to approximately 1 month. One single dose of vYF will be administrated subcutaneously at the 1st visit. Read more about this study

Who is it for?
Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for
Yellow Fever
What is being tested?
Yellow fever vaccine (live)
Could I receive a placebo?
No, everyone receives an active treatment
How many people
254 participants
Where
4 sitesJapan
Study dates
23 Oct 2025to 25 Dec 2025
Phase
Phase 3
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • Aged from 18 years on the day of inclusion*
  • "From 18 years" means from the day of the 18th birthday
  • Participants who are healthy as determined by medical evaluation including medical history and physical examination.
  • Able to attend all scheduled visits and to comply with all study procedures
  • 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.
Show all 30Show fewer
  • OR
  • . Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 4 weeks after study intervention administration.
  • A female 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 01 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 (ICF) has been signed and dated Exclusion Criteria:
  • 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, 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 or laboratory evidence of HIV infection.
  • Known history of hepatitis B or hepatitis C seropositivity
  • Known history of FV infection, Japanese encephalitis (JE) excluded
  • Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the study or to a vaccine containing any of the same substances
  • 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
  • Chronic illness may include, but is not limited to cardiac disorders, renal disorders, auto-immune disorders, diabetes, psychiatric disorders or chronic infection
  • Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (temperature ≥ 37.5°C [or ≥ 99.5°F]). A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided.
  • Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion.
  • 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 (prior to Visit 2 on Day 29), except for influenza vaccination, which may be received at least 2 weeks before study vaccines. This exception includes pandemic influenza vaccines including monovalent pandemic influenza vaccines.
  • Previous vaccination against YF.
  • Receipt of immune globulins, blood, or blood-derived products in the past 6 months.
  • Administration of any anti-viral within 2 months preceding the vaccination and up to the 6 weeks following the vaccination.
  • Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the course of the study in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
  • Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily.
  • 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 28 days of investigational vaccine administration.
  • For participants greater than 60 years at the time of enrolment: any underlying medical condition (eg, cardiovascular disorders, organ failure) which could increase risk of a serious viscerotropic event or serious neurologic events.

Who cannot join

None listed.

Trial locations and contacts

4 sites in 1 country.

Japan4 sites

  • Investigational Site Number : 3920002

    Chūō, Tokyo, 103-0025

  • Investigational Site Number : 3920003

    Shinjuku-ku, Tokyo, 169-0072

  • Investigational Site Number : 3920004

    Taitō City, Tokyo, 111-0036

  • Investigational Site Number : 3920001

    Takatsuki, Osaka, 569-1192

Other trials in Japan

About this study

Official title: A Phase 3, Single Arm, Open Study to Assess the Immunogenicity and Safety of vYF in Adults Aged 18 Years and Over

The purpose of this study is to assess the safety and immunogenicity of vYF in adults aged 18 years and over in Japan.

Study details include:

Read more
  • The study duration will be up to approximately 1 month.
  • One single dose of vYF will be administrated subcutaneously at the 1st visit.
  • The visit frequency will be Day 01 (Visit 01) and Day 29 (Visit 02). One telephone call (TC) will be planned at Day 15.

Number of Participants:

A total of 254 participants is expected to be included in the study with the aim to obtain a total of 203 evaluable participants.

Study Arms and Duration:

Eligible participants will receive, subcutaneously, a single dose of vYF vaccine on Day 1.

The duration of each participation will be approximately 1 month for each participant.

Read the detailed description

Duration of study participation: approximately 1 month for each participant

Conditions
Yellow Fever
Being tested
Yellow fever vaccine (live)
Medical subject headings
Yellow Fever

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Yellow fever vaccine (live)Biological

    Also called vYF vaccine

    Pharmaceutical form:Powder and diluent for suspension for injection-Route of administration:Subcutaneous

Study groups in NCT07222059
Study groupRoleWhat they receive
vYFExperimentalOne single dose of vYF will be administered subcutaneously at the 1st visit
Receives: Biological: Yellow fever vaccine (live)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Percentage of participants with seroconversion to YF virus in YF-naive participants

    Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in neutralizing Ab (NAb) titers as compared to the pre-vaccination value (Day 01)

    Measured: 28 days after one dose of vYF vaccine

Secondary outcomes (10)

  1. Percentage of participants with seroprotection to YF virus

    Seroprotection is defined as NAb titers ≥ 10 (1/dil) at the corresponding timepoint

    Measured: At Day 01 and Day 29

  2. Percentage of participants with seroconversion to YF virus

    Seroconversion rates will be assessed using a YF MN assay Seroconversion is defined as a 4-fold increase in neutralizing Ab (NAb) titers as compared to the pre-vaccination value (Day 01)

    Measured: 28 days after one dose of vYF vaccine

  3. Geometric Mean Titers (GMTs) of neutralizing antibodies against YF virus

    Antibody titers are expressed as GMTs

    Measured: At Day 01 and Day 29

  4. Geometric Mean Titers Ratio (GMTRs) of neutralizing antibodies against YF virus

    GMTRs Day 29/Day 01

    Measured: At Day 01 and Day 29

  5. Number of participants with immediate adverse events

    Immediate adverse events are any unsolicited systemic adverse events reported in the 30 minutes after vaccination

    Measured: Within 30 minutes after vaccination

  6. Number of participants with solicited injection site reactions

    Solicited injection site reactions: injection site pain, injection site erythema, injection site swelling

    Measured: Within 7 days after vaccination

  7. Number of participants with solicited systemic reactions

    Solicited systemic reactions: fever, headache, fatigue, myalgia

    Measured: Within 14 days after vaccination

  8. Number of participants with unsolicited adverse events (AEs), including adverse events of special interest (AESIs)

    Unsolicited (spontaneously reported) AEs, not fulfilling criteria for solicited adverse reactions, including AESIs

    Measured: Within 28 days after vaccination

  9. Number of participants with serious adverse events (SAEs) including serious AESIs

    SAEs including serious AESIs

    Measured: Within 28 days after vaccination

  10. Number of participants with related SAEs and all deaths

    Related SAEs and all deaths

    Measured: From Day 01 to Day 29 after vaccination

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted29 Oct 2025
  2. Study start23 Oct 2025
  3. Primary completion25 Dec 2025
  4. Study completion25 Dec 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Prevention
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
254 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07222059
Sponsor's protocol ID
VYF00011
Other IDs
VYF00011
Status last verified
Feb 2026
First submitted
27 Oct 2025
Last updated
3 Feb 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
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

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Yellow fever vaccine (live) in people with Yellow Fever, run by Sanofi Pasteur, a Sanofi Company at 4 sites in Japan.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 30 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 3 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 4 sites in Japan. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percentage of participants with seroconversion to YF virus in YF-naive participants (time frame: 28 days after one dose of vYF vaccine). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07222059.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Feb 2026.

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