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): 18.0-999.0,  Influenza A male or female aged 18 years or above at the time of the first vaccination Subjects who the investigator believes that they can and will comply with the requirements of the protocol Written informed consent obtained from the subject Satisfactory baseline medical assessment by history and physical examination. Stable health status is defined as the absence of a health event satisfying the definition of a serious adverse event, or a change in an ongoing drug therapy due to therapeutic failure or symptoms of drug toxicity, within one month prior to enrolment Access to a consistent means of telephone contact, which may be either in the home or at the workplace, land line or mobile, but NOT a pay phone or other multiple-user device Female subjects of non-childbearing potential may be enrolled in the study Non-childbearing potential is defined as pre-menarche, current tubal ligation, hysterectomy, ovariectomy or post-menopause Female subjects of childbearing potential may be enrolled in the study, if the subject has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination, and  Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the first dose of the study vaccine or planned use during the study period. Potential subjects in the follow-up phase of a prior investigational study may be enrolled if the investigator's judgment is that it will have no effect on safety, reactogenicity, or immunogenicity endpoints in this study, and that it does not violate the protocol requirements of the prior trial Presence of evidence of substance abuse or of neurological or psychiatric diagnoses which, although stable, are deemed by the investigator to render the potential subject unable/unlikely to provide accurate safety reports Presence of an axillary temperature >= 37.5ºC, or acute symptoms greater than "mild" severity on the scheduled date of first vaccination. NOTE: The subject may be vaccinated at a later date, provided symptoms have resolved, vaccination occurs within the window specified by the protocol, and all other continue to be satisfied Diagnosed with cancer, or treatment for cancer, within the past 3 years Persons with a history of cancer who are disease-free without treatment for 3 years or more are eligible Persons with a history of histological-confirmed basal cell carcinoma of the skin successfully treated with local excision only are excepted and may enrol within 3 years of diagnosis, but other histological types of skin cancer require a 3 year untreated and disease-free window as above Women who are disease-free 3 years or more after treatment for breast cancer and receiving long-term prophylactic hormonal therapy are excepted and may enrol Any confirmed or suspected immunosuppressive or immunodeficient condition including history of human immunodeficiency virus (HIV) infection Chronic administration of immunosuppressants or other immune modifying drugs within 6 months of study enrolment or planned administration during the study period Receipt of any immunoglobulins and/or any blood products within 3 months of study enrolment or planned administration of any of these products during the study period