The Immunologic Basis for an Attenuated Immune Response to the Influenza Vaccine After Repeated Annual Vaccination

This is a prospective pilot study designed to suggest differences in the immunologic response to the seasonal influenza vaccine in people with regular vaccination history compared to those vaccinated less regularly. Participants will receive one dose of the Food and Drug Administration (FDA) approved 2016-2017 seasonal influenza vaccine. Immune system data will be collected at standard time points. The duration of the study for each participant will be approximately 1 month.

This is a prospective pilot study in 20 males and non-pregnant females, 20 to 30 years old, inclusive, who are in good health and meet all eligibility criteria. The study is designed to evaluate differences in the immunologic response to the seasonal influenza vaccine in people with regular vaccination history compared to those vaccinated less regularly.

Participants will be sorted to either Arm A (Naïve) or Arm B (Experienced) based on their vaccination history. Those vaccinated no more than 2 out of the past 5 years will be in Arm A. Those vaccinated 3 or more out of the past 5 years will be in Arm B. Participants will receive one dose of the Food and Drug Administration (FDA) approved 2016-2017 seasonal influenza vaccine. The duration of the study for each participant will be approximately 1 month. Subjects will return for clinic visits on Days 3, 8, 15, and 29 during the month follow-up period following vaccination.

The study has two primary objectives; to evaluate the antibody response to the influenza vaccine in people who are vaccinated regularly and those vaccinated less regularly; the second is to evaluate circulating follicular helper T cells (TFH) in people who are vaccinated regularly and those vaccinated less regularly.

Eligibility Criteria:
Inclusion Criteria:

* Capable of informed consent and provision of written informed consent before any study procedures.
* Capable of attending all study visits according to the study schedule.
* Are in good health, as determined by medical history and targeted physical exam related to this history.
* Oral temperature is less than 38 degrees Celsius.
* Resting pulse rate is between 50 and 115 beats per minute.
* Female subjects of childbearing age must have a negative urine pregnancy test within 24 hours before study vaccination.
* Have received the influenza vaccine at least 3 of the past 5 years or have received the influenza vaccine in 2 or less of the past 5 years.

Exclusion Criteria:

* Have an acute illness within 72 hours before vaccination.
* Have any condition that, in the opinion of the principal investigator, would place the subject at an unacceptable risk of injury or confound the interpretation of the study results.
* Have any acute or chronic medical condition that, in the opinion of the principal investigator, would make vaccination unsafe or interfere with the evaluation of immune response to study vaccination.
* Have a suppressed immune system as a result of illness, immunosuppressive medication, chemotherapy, or radiation therapy within 3 years prior to study vaccination.
* Have known HIV, hepatitis B, or hepatitis C infection.
* Have a known history of autoimmune disease.
* Have taken oral or parenteral corticosteroids of any dose within 30 days before study vaccination.
* Have taken high-dose inhaled corticosteroids within 30 days before study vaccination.
* Have received any licensed live vaccine within 30 days or any licensed inactivated vaccine within 14 days prior to study vaccination.
* Have planned vaccination with any vaccine during the 29-day duration of subject study participation.
* Have received immunoglobulin or other blood products, with the exception of Rho D immunoglobulin, within 90 days prior to study vaccination.
* Have donated blood or blood products within 30 days before study vaccination, plan to donate blood at any time during the 29-day duration of subject study participation, or plan to donate blood within 30 days after the last blood draw.
* Have known hypersensitivity or allergy to eggs, egg protein, chicken protein, or other compounds of the study vaccine.
* Have a history of severe reactions following vaccination with influenza virus vaccines