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

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.