A Phase IV Study to Evaluate the Immune Responses of Subunit Influenza Vaccine in Healthy Adults

Summary

This is a prospective, open-label, parallel time-cohort study designed to characterize the humoral and cellular immune responses induced by a subunit influenza vaccine (manufactured by Ab\&B Bio-tech Co., Ltd.JS) in healthy adults within one month after vaccination. Eligible participants will receive a single intramuscular dose and will be assigned in parallel to one of two blood-sampling schedules to capture the kinetic profile of the immune response: Group A (pre-vaccination, Day 5, and Day 14 post-vaccination) and Group B (pre-vaccination, Day 7, and Day 21 post-vaccination). Hemagglutination inhibition (HI) antibody titers will be measured to assess humoral immunity, while circulating CD4⁺ and CD8⁺ T-cell levels will be analyzed to evaluate cellular immunity. The occurrence of adverse events（AEs) and serious adverse events(SAEs) within 28 days post-vaccination will be recorded.

Timeline

Start

2026-10-11

Primary completion

2026-11-30

Completion

2027-10-11

Drugs

Indications