Effect of Oral Supplement on Influenza Vaccine Long-term Response

NCT07357467 | Not Yet Recruiting

• 1 other identifier: THU01-20251109
• Study Type: observational
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

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. 1.Evaluate the durability of vaccine-induced antibody responses approximately 8 months post-vaccination
2. 2.Assess the persistence of immune memory cells, particularly long-lived plasma cells and memory B cells
3. 3.Compare long-term immune responses between the TUDCA supplementation group and placebo group
4. 4.Provide one blood sample for antibody and immune cell analysis
5. 5.No intervention or vaccination will be administered

Conditions

Influenza; Immunosenescence

Keywords

Tauroursodeoxycholic Acid (TUDCA); Influenza Vaccine; Antibody; Memory B Cells; Long-lived Plasma Cells; Elderly Adults; Humoral Immunity; Nutritional Immunomodulation; Bile Acids

Outcome Measures

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.

  Day 360 (approximately 12 months post-vaccination)

Secondary Outcomes (1)

• B Cell Immune Memory Persistence

  Day 360 (approximately 12 months post-vaccination)

Other Outcomes (1)

• Safety Assessment

  Day 360 (at blood collection visit, 12 months post-vaccination)

Study Arms (2)

TUDCA Supplementation Group

Participants who received TUDCA supplementation (1000 mg/day) during the original study (February-April 2025). In the original trial, participants took 1000 mg of TUDCA (Tauroursodeoxycholic acid) dietary supplement capsules daily. Each capsule contained 500 mg of TUDCA (two capsules per serving). Participants maintained their usual lifestyle during the intervention: Day 0-Day 2 served as an adaptation period; on Day 3, they received a quadrivalent influenza vaccine, followed by continued supplementation until Day 24. This extended follow-up study involves no intervention, only a single fasting blood draw (20 mL) approximately 12 months post-vaccination to assess long-term immune responses.

Placebo Group

Participants who received placebo during the original study (February-April 2025). In the original trial, participants took placebo capsules identical in appearance and smell to the TUDCA capsules. Participants maintained their usual lifestyle during the intervention: Day 0-Day 2 served as an adaptation period; on Day 3, they received a quadrivalent influenza vaccine, followed by continued placebo supplementation until Day 24. This extended follow-up study involves no intervention, only a single fasting venous blood draw (approximately 20 mL) about 12 months post-vaccination to assess long-term immune responses.

Eligibility Criteria

• Age: 60 Years - 70 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study 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.

You may qualify if:

• 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

You may not qualify if:

• 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
• Lost to follow-up or unable to contact

Sponsors & Collaborators

• Tsinghua University: lead
• Second Affiliated Hospital of Bengbu Medical College: collaborator

Study Sites (1)

Tsinghua University

Beijing, Beijing Municipality, 100084, China

Location

Related Publications (3)

• Mordant FL, Price OH, Rudraraju R, Slavin MA, Marshall C, Worth LJ, Peck H, Barr IG, Sullivan SG, Subbarao K. Antibody titres elicited by the 2018 seasonal inactivated influenza vaccine decline by 3 months post-vaccination but persist for at least 6 months. Influenza Other Respir Viruses. 2023 Jan;17(1):e13072. doi: 10.1111/irv.13072. Epub 2022 Nov 30.

  PMID: 36451293 BACKGROUND

• Ellebedy AH. Immunizing the Immune: Can We Overcome Influenza's Most Formidable Challenge? Vaccines (Basel). 2018 Sep 22;6(4):68. doi: 10.3390/vaccines6040068.

  PMID: 30248996 BACKGROUND

• Ferdinands JM, Fry AM, Reynolds S, Petrie J, Flannery B, Jackson ML, Belongia EA. Intraseason waning of influenza vaccine protection: Evidence from the US Influenza Vaccine Effectiveness Network, 2011-12 through 2014-15. Clin Infect Dis. 2017 Mar 1;64(5):544-550. doi: 10.1093/cid/ciw816. Epub 2016 Dec 29.

  PMID: 28039340 BACKGROUND

MeSH Terms

Conditions

Influenza, Human

Condition Hierarchy (Ancestors)

Respiratory Tract Infections; Infections; Orthomyxoviridae Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases

Study Officials

• Cong Tian, Master

  The Second Affiliated Hospital of Bengbu Medical College

  STUDY DIRECTOR

Central Study Contacts

Ai Zhao, PhD

CONTACT

+86 13811131994; aizhao18@mail.tsinghua.edu.cn

Litian Hou, Master

CONTACT

+86 17888846812; hlt24@mails.tsinghua.edu.cn

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 1 Year
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: January 12, 2026
• First Posted: January 22, 2026
• Study Start: March 1, 2026
• Primary Completion: May 1, 2026
• Study Completion (Estimated): July 1, 2026
• Last Updated: January 22, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)