New yellow fever vaccine shows promise in Mid-Stage trial
NCT ID NCT05011123
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This Phase 2 study tests a new yellow fever vaccine (vYF) against the current licensed vaccine (Stamaril) in 690 healthy adults aged 18-60 in Europe and Asia. Participants receive one shot, and researchers measure immune response and safety over 5 years. The goal is to see if the new vaccine works as well as the existing one.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- yellow fever vaccine (vYF)
- What this could lead to
- If successful, this could provide a new, safe, and effective yellow fever vaccine option for adults, potentially improving global vaccine supply.
- What could go wrong
- This is a Phase 2 trial, so results are still early. The new vaccine may not prove as effective or safe as the existing licensed vaccine, Stamaril.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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690 people
The number who actually took part.
- Started
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Oct 2021
- Expected to finish
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Apr 2027
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 59 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Aged 18 years up to 60 years\* on the day of inclusion * 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 (1) or abstinence (1) from at least 4 weeks prior to study intervention administration until at least 4 weeks (2) after study intervention administration. \*18 to 60 years means from the day of the 18th birthday up to the day before the 60th birthday 1. Not applicable for Finland 2. Except for French participants which have to apply 12 weeks contraception 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 1 and the test will be repeated on D29 to confirm the participant is still not pregnant within 28 days of vaccine administration. \- Informed consent form has been signed and dated (3) 3. For participants aged less than 21 years in Singapore, an informed consent form has been signed and dated by both the participant and the parent(s) or another legally acceptable representative * Able to attend all scheduled visits and to comply with all study procedures * For participants enrolled in Asian countries as part of the additional cohort only: know Chinese origin, defined as having at least one biological parent of Chinese origin, and will be self-reported by the participant Exclusion Criteria: Participation at the time of study enrollment (or in the 4 weeks preceding the study vaccination) or planned participation during the first 2 years 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 2 years is permitted, assuming that it does not exclude participation in this study. * 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 4), except for influenza vaccination, which may be received at least 2 weeks before study vaccines (4). This exception includes all influenza vaccines including monovalent pandemic influenza vaccines. * Previous vaccination against a FV 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. * 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 any FV 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 HIV infection (5). * Known history or laboratory evidence of hepatitis B or hepatitis C infection (6). * Personal or 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. * Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion. * Chronic illness (7) 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 or 38°C). 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 planned administration 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. 4. Except for Thai participants 5. HIV Serology testing will be performed on all German participants if no evidence of seronegativity in the 90 days preceding vaccination 6. Hepatitis B and Hepatitis C Serology testing will be performed on all German participants if no evidence of seronegativity in the 90 days preceding vaccination 7. Chronic illness may include, but is not limited to, cardiac disorders, renal disorders, auto-immune disorders, diabetes, psychiatric disorders or chronic infection
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Investigational Site Number : 2460001
Helsinki, 00290, Finland
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Investigational Site Number : 2460002
Tampere, 33100, Finland
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Investigational Site Number : 2460003
Turku, 20520, Finland
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Investigational Site Number : 2500001
Nantes, 44093, France
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Investigational Site Number : 2500004
Pierre-Bénite, 69495, France
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Investigational Site Number : 2500006
Montpellier, 34295, France
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Investigational Site Number : 2500007
Nîmes, 30029, France
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Investigational Site Number : 2500008
Lyon, 69004, France
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Investigational Site Number : 2500009
Paris, 75014, France
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Investigational Site Number : 2760001
Hamburg, 20359, Germany
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Investigational Site Number : 2760002
München, 80802, Germany
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Investigational Site Number : 2760003
Rostock, 18057, Germany
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Investigational Site Number : 2760004
Berlin, 10117, Germany
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Investigational Site Number : 7020001
Singapore, Singapore
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Investigational Site Number : 7020002
Singapore, 119074, Singapore
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Investigational Site Number : 7020003
Singapore, 169608, Singapore
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Investigational Site Number : 7240001
Barcelona, 08036, Spain
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Investigational Site Number : 7240002
Madrid, Madrid, Comunidad de, 28046, Spain
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Investigational Site Number : 7240003
L'Hospitalet de Llobregat, Barcelona [Barcelona], 08907, Spain
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Investigational Site Number : 7240004
Barcelona, Barcelona [Barcelona], 08035, Spain
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Investigational Site Number : 7640001
Bangkok, 10330, Thailand
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Investigational Site Number : 7640002
Bangkok, Thailand
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Investigational Site Number : 7640003
Nonthaburi, 11000, Thailand
More trials for these conditions
Other studies related to the condition(s) this trial covers.
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