This study was designed in two steps with Step 1, a single-center, double-blind, randomized clinical Pilot study and Step 2, a multi-center, single-blind, randomized clinical Pivotal study. The investigator evaluate the immunogenicity and safety of the investigational vaccine in the subjects during their participation in the study.

MG1109 is purified, inactivated influenza viral antigen.

Inclusion Criteria:

• Healthy adults who are available for follow-up during the study

Exclusion Criteria:

• Subjects with history of exposure to the H5N1 subtype or H5N1 subtype vaccine
• Subjects with immune system disorder including immune deficiency disease