This study is to identify the preferred vaccine dosage (of antigen and adjuvant) and schedule (one or two administrations) of the cell-derived H1N1sw monovalent vaccine in healthy adults based on EMEA/CHMP criteria, and safety & tolerability.

Inclusion Criteria:

• Healthy Japanese adults aged 20 to 60 years

Exclusion Criteria:

• History of anaphylaxis, serious vaccine reactions, hypersensitivity to vaccine viral proteins or excipients
• Administration of adjuvanted influenza vaccine or suspected influenza disease within 3 month prior to study start
• Administration of any other vaccines within 4 weeks prior to enrollment expect for seasonal influenza vaccines within 1 week
• History of progressive or severe neurological disorders