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Phase 3 Single Arm, Open Study on vYF in Adults

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

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07222059
Enrollment
254
Registered
2025-10-29
Start date
2025-10-23
Completion date
2025-12-25
Last updated
2026-02-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Yellow Fever

Brief 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. * 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.

Detailed description

Duration of study participation: approximately 1 month for each participant

Interventions

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

Sponsors

Sanofi Pasteur, a Sanofi Company
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
PREVENTION
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

* 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. 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.

Design outcomes

Primary

MeasureTime frameDescription
Percentage of participants with seroconversion to YF virus in YF-naive participants28 days after one dose of vYF vaccineSeroconversion 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)

Secondary

MeasureTime frameDescription
Percentage of participants with seroprotection to YF virusAt Day 01 and Day 29Seroprotection is defined as NAb titers ≥ 10 (1/dil) at the corresponding timepoint
Percentage of participants with seroconversion to YF virus28 days after one dose of vYF vaccineSeroconversion 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)
Geometric Mean Titers (GMTs) of neutralizing antibodies against YF virusAt Day 01 and Day 29Antibody titers are expressed as GMTs
Geometric Mean Titers Ratio (GMTRs) of neutralizing antibodies against YF virusAt Day 01 and Day 29GMTRs Day 29/Day 01
Number of participants with immediate adverse eventsWithin 30 minutes after vaccinationImmediate adverse events are any unsolicited systemic adverse events reported in the 30 minutes after vaccination
Number of participants with solicited injection site reactionsWithin 7 days after vaccinationSolicited injection site reactions: injection site pain, injection site erythema, injection site swelling
Number of participants with solicited systemic reactionsWithin 14 days after vaccinationSolicited systemic reactions: fever, headache, fatigue, myalgia
Number of participants with unsolicited adverse events (AEs), including adverse events of special interest (AESIs)Within 28 days after vaccinationUnsolicited (spontaneously reported) AEs, not fulfilling criteria for solicited adverse reactions, including AESIs
Number of participants with serious adverse events (SAEs) including serious AESIsWithin 28 days after vaccinationSAEs including serious AESIs
Number of participants with related SAEs and all deathsFrom Day 01 to Day 29 after vaccinationRelated SAEs and all deaths

Countries

Japan

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026