Patient description: A 42-year-old healthy woman came to the clinic to have her flu shot in early October. She works in a rehab center and has no underlying disease. It's her first time getting the vaccine this year. She is married for 5 years and uses barrier methods of contraception. Her menstrual cycle is irregular. She does not smoke. She is not on any medications. She exercises regularly for 30 minutes a day at least 5 days a week. She has no history of allergies to any food or drugs. Her past surgical history is significant for tonsillectomy and she is otherwise healthy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-99.0,  Influenza Are males or non-pregnant females age 18 and older, inclusive Women of child-bearing potential (not surgically sterile via tubal ligation, bilateral oophorectomy or hysterectomy or who are not postmenopausal for greater than or equal to 1 year) must agree to practice adequate contraception that may but is not limited to, abstinence, monogamous relationship with vasectomized partner, barrier methods such as condoms, diaphragms, spermicides, intrauterine devices, and licensed hormonal methods during the study for at least 30 days following the last vaccination Are in good health, as determined by vital signs, medical history to ensure any existing medical diagnoses or conditions are stable and not considered clinically significant, and limited physical examination. A stable chronic medical condition is defined as no change in prescription medication, dose, or frequency of medication in the last 3 months and health outcomes of the specific disease are considered to be within acceptable limits in the last 6 months. Any change that is due to change of health care provider, insurance company etc, or that is done for financial reasons, as long as in the same class of medication will not be considered a violation of this criterion. Any change in prescription medication due to improvement of a disease outcome will not be considered a violation of this criterion Have erythrocyte sedimentation rate (ESR) less than 30 mm per hour Are able to understand and comply with planned study procedures Provide written informed consent prior to initiation of any study procedures  Have a known allergy to eggs or other components of the vaccine (including squalene based adjuvants, thimerosal, neomycin, polymyxin, and chicken protein) Have a positive urine or serum pregnancy test within 24 hours prior to vaccination if female of childbearing potential or women who are breastfeeding Have immunosuppression as a result of an underlying illness or treatment, or use of anticancer chemotherapy or radiation therapy (cytotoxic) within the preceding 36 months Have an active neoplastic disease or a history of any hematologic malignancy Have long term use of glucocorticoids including oral, parenteral or high-dose inhaled steroids (>800 micrograms (mcg)/day of beclomethasone dipropionate or equivalent) within the preceding 6 months. (Nasal and topical steroids are allowed.) Have a diagnosis of schizophrenia, bipolar disease, or other major psychiatric diagnosis Have been hospitalized for psychiatric illness, history of suicide attempt, or confinement for danger to self or others, within the past 10 years Are receiving psychiatric drugs (aripiprazole, clozapine, ziprasidone, haloperidol, molindone, loxapine, thioridazine, thiothixene, pimozide, fluphenazine, risperidone, mesoridazine, quetiapine, trifluoperazine, chlorprothixene, chlorpromazine, perphenazine, trifluopromazine, olanzapine, carbamazepine, divalproex sodium, lithium carbonate or lithium citrate). Subjects who are receiving a single antidepressant drug and are stable for at least 3 months prior to enrollment, without de-compensating symptoms will be allowed to be enrolled in the study Have a history of receiving immunoglobulin or other blood product within the 3 months prior to vaccination in this study Received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to vaccination in this study or expect to receive an experimental agent during this study (prior to the Day 386 clinic visit