Actively Recruiting
Immunogenicity of the Yellow Fever Vaccine 17D (YFVax) in Adults With Prior 17D Vaccination A Phase I/II Study Evaluating Immune Response After Re-vaccination
Led by Oregon Health and Science University · Updated on 2025-07-31
35
Participants Needed
1
Research Sites
8 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are investigating how adults who have previously received the yellow fever vaccine 17D respond to receiving the vaccine again. The study aims to understand how prior vaccination affects antibody levels and immune cell responses after re-vaccination. This research will help identify the antibody levels needed for effective protection and support future studies to improve yellow fever vaccination strategies. Participants will receive a single standard dose (0.5 mL) of the yellow fever vaccine 17D given under the skin. The study involves one vaccination arm where all participants are re-vaccinated with the vaccine. This live-virus challenge approach allows researchers to measure immune responses over time and evaluate how well the vaccine boosts immunity. During the study, participants will provide medical and travel histories, blood samples before vaccination, and blood samples approximately every other day for 14 days after vaccination. They will also give a blood sample around 28 days post-vaccination. Participants will complete daily symptom diaries for 14 days and report any symptoms afterward. Researchers will monitor antibody levels, vaccine virus presence in the blood, and immune cell responses to assess vaccine effects and safety over the study period.
CONDITIONS
Brief Title
Immunogenicity of Yellow Fever Vaccine 17D in Adults With Prior 17D Vaccination
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Aged 20 to less than 50 years
- Male or female
- In good health based on medical history, physical exam, and investigator judgment
- Documented prior yellow fever vaccination 8 or more years ago with official records
- Able to comply with all trial procedures and available for follow-up
You will not qualify if you...
- Active infection or fever (temperature 38°C/100.4°F or higher) within 3 days of vaccination
- Known allergy or hypersensitivity to any vaccine components including eggs
- Behavioral or cognitive impairment interfering with safe participation
- History of neurologic disorders, seizures, or neuro-inflammatory diseases
- Any illness or medical history posing additional risk or interfering with the trial
- Immune system impairments including recent steroid use, immunoglobulin or blood product receipt, immunostimulants, chemotherapy, HIV, hepatitis C, or genetic immunodeficiency
- History of spleen or thymus dysfunction
- Serious chronic or progressive diseases such as cancer, insulin-dependent diabetes, cardiac, renal, or liver disease
- Body Mass Index (BMI) of 35 kg/m2 or higher
- Participation in other clinical trials with investigational products within 30 days
- Recent vaccination within 14 days for inactivated or 28 days for live vaccines
- Use of antipyretics or analgesics within 24 hours prior to vaccination
- History of substance or alcohol abuse within past 2 years
- Pregnancy or breastfeeding
- Sexually active women of childbearing potential not using acceptable contraception for at least 2 months prior
- Refusal to use acceptable contraception up to 28 days after vaccination
- Positive or unclear pregnancy test
- Planned vaccination against other diseases or travel to yellow fever endemic areas during the trial
- Screening blood tests showing prior dengue, Zika, West Nile, or Japanese encephalitis infection
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 1 day
Participants receive a single subcutaneous dose of the yellow fever vaccine 17D (YFVax).
1 vaccination visit (in-person)
Duration - 28 days
Participants are monitored for immune response and vaccine viremia after vaccination.
Multiple follow-up visits up to 28 days
Trial Site Locations
Total: 1 location
1
Oregon Health & Science University
Portland, Oregon, United States, 97239
Actively Recruiting
Research Team
W
William Messer, MD PhD
S
Sarah Siegel, PhD
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
PREVENTION
Number of Arms
1
Similar Trials
Frequently Asked Questions
Have more questions? Get in touch with our team for quick support
Not the Right Trial for You?
Explore thousands of other clinical trials that might be a better match.
Sign up to get personalized trial recommendations delivered to your inbox.
Already have an account? Log in here