A Study to Assess the Safety of ASP7374 in Adult Subjects Aged 20 or Older

Inclusion criteria

• 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.

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:

• 1. Within 28 days prior to vaccination with the study vaccine

• Interferon formulation
• Drugs which affect the immune system (e.g., immunosuppressants)
• Systemic corticosteroids and inhaled corticosteroids
• G-CSF and M-CSF
• 2. Within 84 days prior to vaccination with the study vaccine

• Human immunoglobulin products
• Blood products
• Blood transfusion
• 3. Within 180 days prior to vaccination with the study vaccine

• High-dose human immunoglobulin products (≥200 mg/kg)
• History of anaphylactic shock or an allergic reaction such as generalized eruption due to food or drug (including vaccines) allergies, fever ≥39.0°C within 2 days after the previous vaccination (influenza vaccine and others)
• History of seizures (exclude a pyrexial attack in childhood)
• History of Guillain-Barre syndrome or acute disseminated encephalomyelitis (ADEM)
• Body temperature of ≥37.5°C on Day 1 (before vaccination)
• Moderate to severe acute or febrile illness (≥37.5°C) within 7 days prior to vaccination
• Concurrent hepatic disease (exclude fatty liver, hepatic cyst, biliary stone and gallbladder poly, which have laboratory findings only, no clinical symptoms, and not necessary to treat), or AST (GOT) and/or ALT (GPT) of >100 IU/L at screening on Day 1
• Concurrent renal disease (exclude rental cyst and calculus kidney which have laboratory findings only, no clinical symptoms, and not necessary to treat), or creatinine of > 1.5 mg/dL at screening
• Concurrent respiratory disease, hematologic disease, or developmental disorders
• Concurrent or previous heart disease
• Concurrent or previous cerebrovascular disorder
• Concurrent malignancy or diagnosis or treatment of malignancy within 5 years before screening
• Diagnosis of mental disorder including schizophrenia, bipolar disorder, or major depressive disorder or cognitive impairment, or received medications for cognitive impairment
• Concurrent disease interfering with the evaluation of local and systemic reactions