NCT05801978 · Emory University
Durability of Vaccine Responses
What this study is about
The ability of the vaccines today to generate a long-lasting protection against infections varies greatly from one vaccine to another. The yellow fever vaccine (YF-17D) is one of the most successful vaccines ever developed, having been administered to over 600 million people globally. A single vaccination is known to induce durable protection over several decades.
View original scientific description
The ability of the vaccines today to generate a long-lasting protection against infections varies greatly from one vaccine to another. The yellow fever vaccine (YF-17D) is one of the most successful vaccines ever developed, having been administered to over 600 million people globally. A single vaccination is known to induce durable protection over several decades. In contrast, the quadrivalent influenza vaccine (QIV) generates an immunity that wanes quickly with no long-lasting protection.
Interventions
BIOLOGICAL
Live Attenuated Yellow Fever 17D Vaccine
The FDA-approved YF-17D (YF-VAX®) is a live attenuated vaccine manufactured by Sanofi Pasteur as a one-dose vial. The vaccine is prepared by culturing the 17D-204 strain of yellow fever virus, contains sorbitol and gelatin as a stabilizer, and contains no preservative. Each vial of vaccine is supplied with a separate vial of sterile diluent, which contains sodium chloride injection USP (United States Pharmacopeia) without a preservative.
BIOLOGICAL
Quadrivalent seasonal influenza vaccine
The FDA-approved quadrivalent seasonal influenza vaccine contains four distinct strains: two influenza A viruses and two influenza B viruses. The approved seasonal QIV will be purchased from the manufacturer to be given for each season of influenza.
Primary outcome measures
Magnitude of neutralizing antibody (nAB) response against YF-17D in blood
Time frame: Up to 270 days after vaccination
Magnitude of neutralizing antibody responses against YF-17D at 270 days after vaccination among participants who receive YF-17D.
Magnitude of neutralizing antibody (nAb) response against QIV in blood
Time frame: Up to 270 days after vaccination
Magnitude of neutralizing antibody responses against influenza vaccine strains at 270 days after vaccination among participants who receive QIV.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Able to understand and give informed consent.
- Age 18-50 years.
- Participants agree not to take any live vaccines 30 days before or after (14 days for inactivated) vaccination.
- Women of child bearing potential must agree to use effective birth control for the first 3 months of the study. A negative urine pregnancy test must be documented prior to vaccination and prior to tissue sampling procedures.
Exclusion criteria
- History of allergy or serious adverse reaction, including Guillain-Barré syndrome, to a vaccine or vaccine products.
- History of a medical condition resulting in impaired immunity (such as HIV infection, cancer, particularly leukemia, lymphoma, use of immunosuppressive or antineoplastic drugs or X-ray treatment). Persons with previous skin cancers or cured non-lymphatic tumors are not excluded from the study.
- History of Hepatitis B or Hepatitis C infection.
- Chronic clinically significant medical problems that could affect the immune res
Where
- Atlanta, Georgia
- Decatur, Georgia
Collaborators
Defense Advanced Research Projects Agency, Open Philanthropy
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 17, 2026 · Source of record for eligibility and locations