A Phase IV Study to Evaluate the Immune Responses of Subunit Influenza Vaccine in Healthy Adults
ConditionInfluenza
Trial statusRecruiting
Trial phasePhase 4
Trial typeInterventional
Biological sexAll
Age18-59
SponsorAb&B Bio-tech Co., Ltd.JS
About this trial
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.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Adults aged between 18 and 59 years at the time of informed consent signature.
Judged by the investigator to be in good health, based on medical history and physical examination findings obtained at screening.
Able to comprehend and voluntarily provide written informed consent, and willing to comply with all study procedures and requirements.
Disqualifiers
Known allergy to any component of the vaccine, including excipients, formaldehyde, or Triton N-101.
Confirmed influenza infection or influenza-like illness within the past 6 months, or close contact with a confirmed influenza case within 14 days prior to the screening visit.
Receipt of any influenza vaccine (licensed or investigational) within the past 6 months.
Receipt of any licensed vaccine within 28 days prior to study vaccination, or planned receipt of any licensed vaccine within 28 days after study vaccination.
Trial design
Design model
Parallel
Treatments tested in this trial
Group A
Biological/VaccineParticipants will receive one dose of Subunit Influenza Vaccine
Group B
Biological/VaccineParticipants will receive one dose of Subunit Influenza Vaccine
Treatment groups
138 Participants
are divided into 2 treatment groupsGroup A: Group AExperimental treatment 1 intervention
Group B: Group BExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
GMTs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Influenza A includes H1N1 and H3N2; influenza B includes Victoria-lineage. Geometric mean HI antibody titer for each strain will be calculated with two-sided 95% CIs.
Time frame
Day 21 post-vaccination (Group B)2
GMIs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Geometric mean fold increase in HI antibody titer from pre-vaccination (Day 0) to Day 21 for each strain, with two-sided 95% CIs.
Time frame
Day 21 post-vaccination (Group B)3
SCRs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Seroconversion is defined as either a pre-vaccination HI titer \<1:10 with a post-vaccination titer ≥1:40, or a pre-vaccination HI titer ≥1:10 with at least a four-fold increase in titer.
Time frame
Day 21 post-vaccination (Group B)4
SPRs of HI antibodies against the three vaccine strains (Group B, Day 21 post-vaccination)
Seroprotection is defined as an HI titer ≥1:40.
Time frame
Day 21 post-vaccination (Group B)Secondary outcomes
1
GMTs of HI antibodies against the three vaccine strains (Group A, Day 5 and Day 14 post-vaccination)
Influenza A includes H1N1 and H3N2; influenza B includes Victoria-lineage. GMTs will be calculated for each strain at Day 5 and Day 14 in Group A.
Time frame
Day 5 and Day 14 post-vaccination (Group A)2
GMTs of HI antibodies against the three vaccine strains (Group B, Day 7 post-vaccination)
Influenza A includes H1N1 and H3N2; influenza B includes Victoria-lineage. GMTs will be calculated for each strain at Day 7 in Group B.
Time frame
Day 7 post-vaccination (Group B)3
Antigen-specific CD4⁺ T-cell counts and proportions (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
Number and percentage of antigen-specific CD4⁺ T cells will be measured by flow cytometry at all three time points in Group A and Group B.
Time frame
Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B:)4
Antigen-specific CD8⁺ T-cell counts and proportions (Group A: Day 0, Day 5, Day 14; Group B: Day 0, Day 7, Day 21)
Number and percentage of antigen-specific CD8⁺ T cells will be measured by flow cytometry at all three time points in Group A and Group B.
Time frame
Day 0, Day 5, Day 14 (Group A); Day 0, Day 7, Day 21(Group B)Sponsors and contacts
Click on the lead sponsor to view all of their trials.
Ab&B Bio-tech Co., Ltd.JS
Lead sponsor
Zhejiang Provincial Center for Disease Control and Prevention
Collaborator
Shangyu District Center for Disease Control and Prevention
Collaborator
Source ClinicalTrials.gov