Immunogenicity, Safety, Reactogenicity, Efficacy, Effectiveness and Lot Consistency of FluBlok

Inclusion Criteria: * Healthy adult aged 18-49 years. * Provided informed consent prior to any study procedures. * Able to comply with all study procedures. * Available for follow-up for the duration of the influenza season. * Women of child-bearing potential must have had a negative urine pregnancy test at the time of randomization and must be willing to use an adequate form of contraception (includes abstinence, condom with spermicide, licensed hormonal contraceptive, intrauterine device \[IUD\], monogamous relationship with a vasectomized partner) during the course of the study. Exclusion Criteria: * Long-term use of oral steroids, parenteral steroids, or high-dose inhaled steroids (greater than \[\>\] 800 mcg/day of beclomethasone dipropionate or equivalent) within the preceding 6 months (Nasal and topical steroids were allowed). * Presence of high-risk conditions or other characteristics were considered to be indication for influenza vaccination, as defined by the Advisory Committee on Immunization Practices. * Acute febrile illness (defined as having a temperature greater than or equal to \[\>=\]100 degrees Fahrenheit) or upper respiratory tract illness within 72 hours of vaccination. Participants with acute febrile illness were rescheduled after fever resolved. * Use of experimental vaccines or any influenza vaccine other than FluBlOk after May 31st 2007 for the 2008 Southern Hemisphere or 2007 to 2008 Northern hemisphere epidemic seasons. * Immunosuppression as a result of an underlying illness or treatment, or used anticancer chemotherapy or radiation therapy within the preceding 36 months. * Any malignancy diagnosed or treated actively during the past five (5) years, with two (2) exceptions. Participant with any history of lymphoproliferative disorder were excluded. However, participants with a history of localized non-melanotic skin cancer were eligible. * Receipt of any other licensed vaccines within 2 weeks (for inactivated vaccines) or 4 weeks (for live vaccines) prior to enrollment in this study. * Receipt of an experimental agent (vaccine, drug, biologic, device, blood product or medication) within 1 month prior to enrollment in this study, or expected to receive an experimental agent during study period. * Receipt of parenteral immunoglobulin or other blood product within the three months prior to study vaccination. * Major psychiatric diagnosis including schizophrenia, bipolar disease or other major depression, or any diagnosis of dementia or associated concomitant medications (e.g., Aricept) used for treating dementia. * Known active human immunodeficiency virus, hepatitis B, or hepatitis C infection. * History of alcohol or drug abuse in the last 5 years. * Not available for three or more consecutive weeks during flu surveillance period. * Any acute or chronic condition that, in the opinion of the investigator, would render vaccination unsafe or interfere with the evaluation of responses or render the participant unable to meet the requirements of the protocol.