The purpose of this study is to compare immunogenicity and safety of ASP7374 (cell-culture derived influenza vaccine) with those of approved egg-derived trivalent inactivated vaccine (TIV) in adults ≥20 and <65 years.

Inclusion Criteria:

• Healthy or medically stable, as judged on the basis of history and concurrent diseases.
• Subject understands procedure of the protocol and is willing to comply with the protocol.
• Written informed consent has been obtained.

Exclusion Criteria:

• Scheduled to receive another vaccine during the study.
• Received influenza HA vaccine within 180 days prior to screening.
• Received or scheduled to receive a live vaccine within 28 days prior to vaccination with the study vaccine, and received or scheduled to receive an inactivated vaccine or a toxoid within 7 days prior to vaccination with the study vaccine.
• Diagnosis of immune deficit in the past, has a family member (within the third degree of kinship) with a diagnosis of congenital immunodeficiency syndrome.
• Received one of the following medications or treatment prior to vaccination with the study vaccine.
• Received one of the following medications or treatment prior to vaccination with the study vaccine: Interferon formulation, Drugs which affect the immune system, corticosteroids, G-CSF, M-CSF, Human immunoglobulin products, Blood products, Blood transfusion
• History of anaphylactic shock or an allergic reaction such as generalized eruption due to food (including chicken, poultry, foodstuffs derived from chicken, et al.) or drug (including vaccines) allergies, fever ≥39.0°C within 2 days after the previous vaccination (influenza vaccine and others)
• History of seizures, except for febrile seizures in childhood