Effect of Oral Supplement on Influenza Vaccine Long-term Response

Condition(s) studied

Study 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. 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

Primary outcome measure(s)

• Long-term Influenza-Specific Antibody Levels Post-Vaccination — Day 360 (approximately 12 months 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.

Trial sites (1)

More Tsinghua University trials in China

Other trials for the same condition