Clinical trial NCT01244802: Characterization of Human Memory Immune Responses to Prior Yellow Fever Vaccination
Official title: Characterization of Human Memory Immune Responses to Prior Yellow Fever Vaccination
Study type: OBSERVATIONAL
Overall status: ENROLLING_BY_INVITATION
Conditions: Yellow Fever Vaccine
Lead sponsor: Emory University
Sponsor class: OTHER
Collaborators: name: National Institute of Allergy and Infectious Diseases (NIAID)
First posted: 2010-11-19
Enrollment: 300
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: OTHER
Time perspective: CROSS_SECTIONAL
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Healthy adults between the ages of 18 to 45 years or 55 or above who previously received the yellow fever vaccine

Brief summary: The objective of this study is to study immune memory generated against the yellow fever (YFV) vaccine in participants who have previously received the vaccine. Volunteers will not receive vaccine shots; only immune responses to previous yellow fever vaccination will be studied. The study involves one or multiple blood draws.

Detailed description: The goal of this study is to characterize immune memory in humans who have previously received yellow fever vaccine. The project is designed to study the magnitude and persistence of both humoral, and cell-mediated immune memory generated post-vaccination. Since aging has an effect on the immune system (eg. decreased thymic output, replacement of hematopoietic cells in the bone marrow with adipocytes), the researchers will analyze the young adults (aged 18-45 years) and the older vaccinees (55 years or older) in separate groups.

The specific aims of the study are to:

* Determine the phenotypic and functional characterization of memory T cell responses to yellow fever vaccination
* Determine neutralizing antibody titer after yellow fever vaccination

Eligibility criteria: Inclusion Criteria:

* Able to understand and give informed consent
* Age 18-45 years (Group 1) or 55 years and above (Group 2) at the time of yellow fever vaccination
* Documentation (international certificate of vaccination (yellow card) or medical record) indicating receipt of yellow fever vaccine.

Exclusion Criteria:

* Recipient of any vaccines within 30 days before the study visit (not applicable to older adults)
* History of a progressive and severe chronic medical condition resulting in impaired immunity (such as diabetes, kidney or liver dysfunction)
* Required use of immunosuppressive medications
* Reporting HIV, Hepatitis B (surface antigen positive) or Hepatitis C infections (antibody positive) on the medical/health history form
* Recipient of a blood product or immune globulin product within 42 days of study visit
* Reporting pregnancy

Primary outcomes:
measure: Determine the phenotypic and functional characterization of memory T cell responses to YF vaccination
timeFrame: Immune responses will be measured from at least 30 days after yellow fever vaccination.
Secondary outcomes:
Other outcomes:
Locations:
city: Decatur
country: United States
facility: The Hope clinic of Emory Vaccine Center
state: Georgia
Study officials:
affiliation: Emory University
name: Rafi Ahmed, PhD
role: STUDY_CHAIR
affiliation: Emory University
name: Srilatha Edupuganti, MD
role: PRINCIPAL_INVESTIGATOR
References: