A Study to Assess the Immunogenicity and Safety of CSL's 2009 / 2010 Formulation of Enzira® Vaccine in Healthy Volunteers

Inclusion Criteria: * Males or females aged ≥ 18 years at the time of providing informed consent * Participants are capable of understanding the purposes and risks of the study and are able to provide written informed consent * Willing and able to adhere to all protocol requirements * Able to provide a sample of approximately 17 mL of venous blood on two separate occasions without undue distress/discomfort * Females of child bearing potential (i.e. ovulating, pre-menopausal, not surgically sterile) must be abstinent or be willing to use a medically accepted contraceptive regimen for the duration of the study Exclusion Criteria: * Known hypersensitivity to a previous dose of influenza vaccine or allergy to eggs, chicken protein, neomycin, polymyxin, or any components of the Enzira® vaccine * Clinical signs of an active infection and/or an elevated oral temperature (≥ 38.0°C) at study entry * A clinically significant medical or psychiatric condition * A confirmed or suspected immunosuppressive condition * History of seizures * History of Guillain-Barré Syndrome * Vaccination with a seasonal influenza virus vaccine or with an experimental influenza virus vaccine in the 6 months preceding study entry * Currently receiving treatment with radiotherapy or cytotoxic drugs, or have received such treatment within the 6 months preceding administration of Enzira® vaccine * Currently receiving systemic glucocorticoid therapy (excluding topical or inhaled preparations) or have received such therapy within the 3 months preceding study entry * Currently receiving immunoglobulins and/or any blood products or have received such treatment within the 3 months preceding the administration of Enzira® vaccine * Currently participating in another investigational study or recent study participation ending 3 months preceding administration of Enzira® vaccine * Currently receiving treatment with warfarin or other anticoagulants * Evidence or history of substance or alcohol abuse within the 12 months before study entry * Females of child bearing potential who are planning to become pregnant or planning to discontinue contraceptive precautions during the study period * Females who are pregnant or lactating * Any issues that, in the opinion of the investigator, would render the subject unsuitable for study participation