Phase 2/3 Clinical Trial to Evaluate the Immunogenicity and Safety of GC3114B in Adults Aged 65 Years or Older

This is a multicenter, randomized, double-blind, active-controlled, parallel-group clinical trial in adults aged 65 years or older. The study will evaluate the safety of GC3114B and assess whether its immune response is non-inferior to that of the active control. After providing written informed consent, participants will undergo screening to determine whether they are eligible. Eligible participants will be randomly assigned to a study group and receive a single dose of the investigational product on Day 0. Participants will record solicited adverse events in a subject diary from Day 0 through Day 7. The study site will contact participants by telephone on Day 7 to check on adverse events, concomitant medications, and diary completion. On Day 28, participants will visit the study site for safety follow-up and blood sampling. Participants will be monitored for serious adverse events for 6 months.

Inclusion Criteria: * Adults aged 65 years or older at the time of IP vaccination * Subjects who have voluntarily decided to participate in the study after receiving and understanding a detailed explanation of the study and provided written informed consent to comply with the precautions Exclusion Criteria: * History of severe hypersensitivity reactions after previous influenza vaccination or to eggs or any component of the vaccine (see Section 6.1) (e.g., anaphylaxis) * Record of an influenza vaccination within 24 weeks prior to IP vaccination * Known or suspected history of impaired immune function, including congenital or acquired immunodeficiency disorders * History or family history of Guillain-Barre syndrome