Scientists use yellow fever vaccine to map immune System's battle plan

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Able to understand and give informed consent 2. Age 18-45 years 3. Participant agrees not to take any live vaccines 30 days before or after (14 days for inactivated, including coronavirus disease 2019 (COVID-19) vaccination) yellow fever vaccination 4. Women of child bearing potential must agree to use effective birth control throughout the duration of the study. A negative urine pregnancy test must be documented prior to vaccination. Participants who have a history of surgical sterilization or post-menopausal status \>1 year, are not required to have a pregnancy test. Exclusion Criteria: 1. Prior receipt of a yellow fever vaccine 2. Lived in a country/area which is endemic for yellow fever 3. Travel to country/area which is endemic for yellow fever. Subject to investigator discretion 4. History of previous yellow fever, West Nile, Dengue, St. Louis encephalitis, Japanese encephalitis vaccination or infection 5. Any history of allergy to eggs, chicken or gelatin or to any previous vaccine 6. A 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 7. History of HIV infection 8. Active Hepatitis B or Hepatitis C infection 9. COVID-19 infection in the last 30 days. Symptoms of COVID-19 must be completely resolved before yellow fever vaccine receipt. 10. History of any chronic medical conditions that are considered progressive (ex, diabetes, heart disease, lung disease, liver disease, kidney disease, gastrointestinal diseases and uncontrolled hypertension). Use of systemic immunosuppressive medications (ex, prednisone) for 2 weeks or more in the past 3 months 11. History of excessive alcohol consumption, drug abuse, psychiatric conditions, social conditions or occupational conditions that in the opinion of the investigator would preclude compliance with the trial 12. Thymus gland problems (such as myasthenia gravis, DiGeorge syndrome, thymoma) or removal of thymus gland or history of autoimmune disorder 13. Recipient of a blood products or immune globulin product within 42 days of the vaccination visit. Participants who received COVID monoclonal antibodies (mAbs) for treatment are not excluded 14. Pregnant women and nursing mothers or women who are planning to become pregnant for the duration of the study 15. Any condition in the opinion of the investigator that would interfere with the proper conduct of the trial