Effect of Oral Supplement on Influenza Vaccine Long-term Response
Trial statusNot yet recruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age60-70
SponsorTsinghua University
About this trial
This is a follow-up study of a previously completed randomized controlled trial (NCT06827873) that investigated the effects of oral supplements on influenza vaccine response in adults aged 60-70 years. The original study was completed in April 2025, with participants receiving either TUDCA (Tauro Ursodesoxy Cholic Acid) supplementation, fatty acid supplementation, or placebo during influenza vaccination.
The primary objectives of this follow-up study are to:
1. Evaluate the durability of vaccine-induced antibody responses approximately 8 months post-vaccination 2. Assess the persistence of immune memory cells, particularly long-lived plasma cells and memory B cells 3. Compare long-term immune responses between the TUDCA supplementation group and placebo group
This observational follow-up involves a single visit where participants will:
1. Provide one blood sample for antibody and immune cell analysis 2. No intervention or vaccination will be administered
The study will specifically focus on B cell subsets through flow cytometry analysis, including total B cells, memory B cells, plasma cells, and long-lived plasma cells. This research aims to determine whether TUDCA supplementation can enhance the durability of vaccine-induced immunity in older adults.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Originally assigned to either the TUDCA supplementation group or placebo control group
No influenza vaccination or other vaccines received between April 2025 and December 2025
Willing to participate in this follow-up study and sign supplementary informed consent
Stable health condition
Disqualifiers
Started using immunosuppressants or hormonal medications after the original study
Experienced serious illness or hospitalization within the past month, or planning surgery soon
Experienced fever, cold, severe diarrhea, or taken influenza antiviral medications within the past month
Unable or unwilling to participate in blood collection
Trial population
This extended follow-up study includes participants from the original randomized controlled trial (Protocol ID: THU01-20240201; NCT06827873) conducted between February and April 2025. Thirty older adults (aged 60-70 years) were previously randomized to either the TUDCA group (n=15) or placebo group (n=15). All completed the 25-day intervention, received quadrivalent influenza vaccine on Day 3, and finished all Day 24 assessments. Participants were recruited from community health centers affiliated with the Second Affiliated Hospital of Bengbu Medical College, Anhui, China, and provided written informed consent for both the original and follow-up studies.
Trial design
Design model
Cohort
Time perspective
Prospective
Treatments tested in this trial
Not listed
Trial groups
30 Participants
are grouped into 2 trial groupsGroup A: TUDCA Supplementation Group
Group B: Placebo Group
Trial outcomes
Primary outcomes
1
Long-term Influenza-Specific Antibody Levels Post-Vaccination
Evaluate influenza virus-specific IgG antibody levels at approximately 12 months post-vaccination to assess the durability of vaccine-induced humoral immunity. Antibody levels will be measured for all four strains contained in the quadrivalent influenza vaccine (H1N1, H3N2, B/Victoria, B/Yamagata) using ELISA or hemagglutination inhibition (HI) assay.
Time frame
Day 360 (approximately 12 months post-vaccination)Secondary outcomes
1
B Cell Immune Memory Persistence
Assess B cell subsets through flow cytometry analysis, including Total B cells (CD19+), Memory B cells (CD19+ \& CD27+), Plasma cells (CD19+, CD38+ \& CD27+) and Long-lived plasma cells (CD19+, CD38+ \& CD138+). Compare the persistence of these immune memory cell populations between TUDCA supplementation and placebo groups to evaluate whether TUDCA enhances long-term cellular immunity.
Time frame
Day 360 (approximately 12 months post-vaccination)Other outcomes
1
Safety Assessment
Record and monitor any adverse events related to blood collection, including pain, dizziness, bruising, or hematoma formation. In addition, participants will be asked to report any delayed or persistent adverse effects that may have occurred since completion of the original study, including those potentially associated with prior vaccination or nutritional supplementation. These events will be documented and evaluated descriptively.
Time frame
Day 360 (at blood collection visit, 12 months post-vaccination)Sponsors and contacts
Click on the lead sponsor to view all of their trials.
Tsinghua University
Lead sponsor
Second Affiliated Hospital of Bengbu Medical College
Collaborator
Source ClinicalTrials.gov
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