Inclusion Criteria:

• Has the subject given written informed consent?
• Is the subject in good health?
• Is the subject between the ages of 50 and 74 years?
• Is the subject able to follow study procedures?
• Is the subject expected to be available for the duration of the study?
• Does the subject agree NOT to donate blood during the length of the study or in the 56 days after the last blood draw?
• If the subject has any medical conditions, are those conditions stable—where stable is defined as not requiring either a significant change in therapy or a hospitalization in the last 12 weeks?

Exclusion Criteria:

• Has subject received this year’s 2010-2011 influenza vaccine outside of this study?
• Has the subject had a severe reaction that was associated with the influenza vaccine?
• Is subject allergic to egg proteins (egg or egg products) and chicken proteins?
• Does the subject have a history of Guillain-Barré syndrome?
• Does the subject have trouble with blood draws?
• Does the subject have a known or suspected immunodeficiency or receiving treatment with immunosuppressive therapy including cytotoxic agents or systemic corticosteroids (e.g., for cancer, HIV, or autoimmune disease?
• Has the subject received systemic corticosteroids for treatment of an acute illness in the last 30 days?
• Does the subject have a serious chronic disorder including metastatic malignancy, severe chronic obstructive pulmonary disease requiring supplemental oxygen, end stage renal disease with or without dialysis, clinically unstable cardiac disease, or any other disorder that in the investigators opinion precludes the subject from participating in the study?
• Has the subject received any blood products, including immunoglobulin, within 6 months of study enrollment?
• Is the subject receiving anticoagulant therapy or have a history of bleeding diathesis that would contraindicate intramuscular (IM) injection? Note: antiplatelet drugs such as aspirin and clopidrogel are permitted.
• Does the subject intend to receive any other investigational vaccine or agent during the course of the study?
• If the flu season has begun, has subject been diagnosed with the flu or flu like illness or had flu-like symptoms this season?
• Does subject have any medical condition that would, in the opinion of the investigator, interfere with the evaluation of the study objectives?