This is a phase I, double-blind, randomized, placebo-controlled trial with two groups of subjects to receive seasonal trivalent inactivated split virion influenza vaccine (A/H1N1; A/H3N2 and B strains) or placebo (phosphate buffered saline). A total of 60 healthy male and female adults 18 through 45 years of age will be randomized to receive vaccine (30) or placebo (30).

This is a phase 1, single center, double blinded, randomized, placebo-controlled study. Sixty (60) healthy male and female adults, 18 to 45 years of age, will be enrolled into the trial. Subjects will be randomized 1:1 to one of two treatment allocations: 30 to vaccine, 30 to placebo. The study will utilize a "randomized block design" to assure a balance of 1:1 vaccine and placebo when all subjects are enrolled. The study will be double blinded, meaning the study subjects, investigators, and the sponsor will be unaware of the treatment allocated to each subject until the clinical trial database is declared final and locked. The study should take about 5 months to complete, with each subject involved for 3 months from the day of injection. The justification for the 3 month follow up, rather than 6 month follow up is that this is an inactivated vaccine that follows very standard manufacturing practices with standard antigens. The safety of inactivated influenza vaccines is well-established. Adding length to the follow up results in delays in future testing of the vaccine for licensure.

Inclusion Criteria:

• Male or female adult 18 through 45 years of age at the enrollment visit.
• Literate (by self-report) and willing to provide written informed consent.
• Healthy, as established by the medical history, physical examination, and screening laboratory evaluations.
• Capable and willing to complete Diary Cards and willing to return for all follow-up visits.
• For females, willing to utilize reliable birth control measures (e.g., intrauterine device, hormonal contraception, condoms) through the Day 22 visit.

Exclusion Criteria:

• Participation in another clinical trial involving any therapy within the previous three months or planned enrollment in such a trial during the period of this study.
• Receipt of any non-study vaccine within 4 weeks prior to enrollment or refusal to postpone receipt of such vaccines until after the Day 22 visit.
• Current or recent (within 2 weeks of enrollment) acute illness with or without fever.
• Receipt of immune globulin or other blood products within 3 months prior to study enrollment or planned receipt of such products prior to the Day 22 visit.
• Chronic administration (defined as more than 14 consecutively-prescribed days) of immunosuppressants or other immune-modulating therapy within six months prior to study enrollment. (For corticosteroids, this means prednisone or equivalent, 0.5 mg per kg per day; topical steroids are allowed.)
• History of asthma.
• Hypersensitivity after previous administration of any vaccine.
• Suspected or known hypersensitivity to any of the study vaccine components, including chicken or egg protein, antibiotics, and rubber (from the vaccine vial stoppers).
• Acute or chronic clinically significant pulmonary, cardiovascular, hepatobiliary, metabolic, neurologic, psychiatric or renal functional abnormality, as determined by medical history, physical examination or clinical laboratory screening tests, which in the opinion of the investigator, might interfere with the study objectives.
• History of any blood or solid organ cancer.
• History of thrombocytopenic purpura or known bleeding disorder.
• History of seizures.
• Known or suspected immunosuppressed or immunodeficient condition of any kind.
• Confirmed hepatitis B virus (HBV) or hepatitis C virus (HCV) infection
• Known human immunodeficiency virus (HIV) infection (self-report).
• Known active tuberculosis or symptoms of active tuberculosis, regardless of cause (self-report).
• History of chronic alcohol abuse and/or illegal drug use.
• Pregnancy or lactation. (A negative pregnancy test will be required before administration of study product for all women of childbearing potential.)
• History of Guillain-Barré Syndrome
• Any condition that, in the opinion of the investigator, would increase the health risk to the subject if he/she participates in the study or would interfere with the evaluation of the study objectives.

Note: Minor out-of-range laboratory values no greater than Grade 1 will not be considered to be exclusionary at screening.

90 days

We included AEs that occurred any time after the vaccine/placebo was administered , whether or not deemed "related" to the product, and are not solicited (specifically asked of the subject) unless they started after 7 days post-vaccination. In this study, laboratory results were considered AEs when (1) the result was judged to be clinically significant by the Principal Investigator, regardless of grade; or (2) the result is Grade 2 or higher.

Note: all unsolicited AEs were mild in intensity.