The purpose of this study is to evaluate the safety and immunogenicity of IL-YANG Inactivated Split Influenza Vaccine (IL-YANG FLU Vaccine Prefilled Syringe INJ.) administered as a single intramuscular injection.

This was a multi-center, randomized, double-blind, active-controlled study.

Before initiation of any protocol-specific activities, written informed consent was obtained from each patient and their legally acceptable representatives (consent of the legally acceptable representative was required for children younger than 10 years of age, and for the some sites, for children younger than 7 years of age). Subjects who met all of the eligibility criteria after screening assessments as specified in the protocol, were randomized into the test group or the comparator group in a ratio of 5 to 1 according to the pre-generated site-specific randomization table, and received a single dose or two doses of the study vaccine. The investigator performed the efficacy (immunogenicity) and safety assessments throughout the study. Efficacy data were collected at Visit 1 (prior to vaccination) and at the end-of-study visit for efficacy (immunogenicity) assessments, and for safety assessment, subjects and their legally acceptable representatives were instructed to record any treatment-emergent adverse event in Patient Diary cards.

For all randomized subjects, blood sample was obtained prior to vaccination, and the study vaccine 0.5mL or 0.25mL was administered to the deltoid muscle or anterolateral thigh muscle. For children aged from 6 months to <9 years of age who had not been previously exposed to influenza virus or had not previously received influenza vaccine, another dose of the study vaccine was administered 4 to 5 weeks after the first dose. Blood samples were collected 4 to 5 weeks after the last dose of the study drug for the assessment of antibody titer. All subjects were followed for 6 months after the last dose of the study drug for the safety assessments, and Month 6 follow-up visit was the end-of-study visit.

Inclusion Criteria:

• Healthy men or women aged from 6 months to < 18 years
• Subjects were born after full term pregnancy (37 weeks)
• Voluntary written informed consent was obtained from the subject and the subject's legally acceptable representative (consent of legally acceptable representative was required for subjects younger than 10 years of age (and for subjects younger than 7 years of age for the some institutions)).

Exclusion Criteria:

• Subject with a known allergy to eggs, chicken, neomycin, gentamicin or any components of the study vaccine
• Subject who had received an influenza vaccine within the last 6 months
• Subject who has, or has a family history of, an immune system disorder including immune deficiency disease
• Subject with a history of Guillain-Barre syndrome
• Subject with Down's syndrome or cytogenetic disorders.
• Subject with severe chronic disease which in the investigator's opinion would not make the subject a good candidate for the clinical trial
• Subject with hemophilia or being treated with an anticoagulant, who are at increased risk of serious bleeding during intramuscular injection
• Subject who had an acute fever with body temperature > 38.0 Cº within 72 hours prior to administration of the study vaccine
• Subject who had previously received another vaccine within 28 days before administration of the study drug, or is scheduled to receive another vaccine during the study period.
• Subject who had received immunosuppressant or immune modifying drug within the last 3 months prior to administration of the study vaccine
• Subject who had previously received immunoglobulin or blood-derived products within the last 3 months prior to administration of the study vaccine, or is expecting to be treated with immunoglobulin or blood-derived products during the study.
• Subject who had participated in another experimental study within 30 days prior to administration of the study vaccine
• Subject with other clinically significant medical or psychological condition who in the investigator's opinion would not be suitable for the study.