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NCT Number: NCT07232745

Mucosal and Systemic Immune Responses Induced by an Intranasal Influenza Live Attenuated Vaccine

This is a single-center, open-label, single-arm clinical trial designed to evaluate the mucosal and systemic immune responses induced by an intranasal influenza live attenuated vaccine, and to explore the correlation between the two. The study plans to recruit 60 healthy volunteers aged 14-17 years, with a male-to-female ratio of 1:1. Participants and their guardians must be able and willing to comply with the clinical trial protocol and provide informed consent. Eligible participants will receive a single 0.2 mL dose of LAIV prior to the influenza season. Information on participants' historical vaccination records, baseline demographic data, and past health status will be collected. Nasal specimens (nasal secretions and nasal mucosal cells) and blood samples (serum and PBMCs) will be collected on Day 0 (before vaccination), Day 7, and Day 28 after vaccination for transcriptome sequencing and immunogenicity analysis. In addition, fecal samples will be collected on Day 0 (before vaccination), Day 7, and Day 28 after vaccination for intestinal microbiota detection.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

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Key information

Conditions

Influenza Infections Influenza, Human Orthomyxoviridae Infections RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

14 year–17 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Haizhou District Center for Disease Control and Prevention

Lianyungang, Jiangsu, China

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Individuals aged 14-17 years.
  • Volunteers and their guardians are able and willing to comply with the requirements of the clinical trial protocol and sign the informed consent form.

Exclusion criteria

  • Allergy to any component of the vaccine product, including eggs, excipients, or gentamicin sulfate.
  • Individuals with acute illnesses, severe chronic illnesses, acute exacerbations of chronic illnesses, or fever.
  • Pregnant or lactating women.
  • Individuals with Leigh syndrome who are receiving treatment with aspirin or aspirin-containing medications.
  • Individuals with immunodeficiency, immunosuppression, or those undergoing immunosuppressive therapy.
  • Individuals with uncontrolled epilepsy, other progressive neurological disorders, or a history of Guillain-Barré syndrome.
  • Individuals with rhinitis or asthma.
  • Individuals with a personal or family history of seizures, chronic diseases, epilepsy, or allergic tendencies.
  • Individuals who have received immunoglobulin injections within the last 3 months prior to vaccination.
  • Individuals who have used other live attenuated vaccines within 1 month prior to vaccination.
  • Individuals planning to use antiviral drugs for influenza within 48 hours before or 2 weeks after vaccination.
  • Individuals planning to use any other intranasal medication within 2 days after vaccination.
  • Subjects with underlying gastrointestinal diseases, including but not limited to inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), chronic diarrhea, peptic ulcer, and intestinal polyps.
  • Subjects with metabolic diseases, such as diabetes mellitus, obesity (BMI ≥ 25.9 kg/m²), hyperlipidemia, or metabolic syndrome.
  • Subjects who have used antibiotics, probiotics, or other drugs that may affect the intestinal microbiota within the past 3 months.
  • Other circumstances in which the subject is deemed unsuitable for participation in the study by the investigator.

Treatment and study plan

LAIV

Biological

This vaccine is produced by Changchun BCHT Biotechnology Co.

Primary outcomes

  1. The level of IgG antibodies (ng/mL) against the vaccine strain in serum at 28 days post-vaccination.

    Time frame: Day 28 post-vaccination

    Measured by Enzyme-Linked Immunosorbent Assay (ELISA)

  2. The level of sIgA antibodies (AU/mL) against the vaccine strain in nasal secretions at 28 days post-vaccination.

    Time frame: Day 28 post-vaccination

    Measured by Enzyme-Linked Immunosorbent Assay (ELISA)

Secondary outcomes

  1. The levels of cytokines in serum at 7 days post-vaccination.

    Time frame: Day 7 post-vaccination

    Measured by Meso Scale Discovery

  2. The levels of cytokines in nasal mucosal secretions at 7 days post-vaccination.

    Time frame: Day 7 post-vaccination

    Measured by Meso Scale Discovery

  3. The levels of cytokines in serum at 28 days post-vaccination.

    Time frame: Day 28 post-vaccination

    Measured by Meso Scale Discovery

  4. The levels of cytokines in nasal mucosal secretions at 28 days post-vaccination.

    Time frame: Day 28 post-vaccination

    Measured by Meso Scale Discovery

  5. The level of IgG antibodies (ng/mL) against the vaccine strain in serum at 7 days post-vaccination.

    Time frame: Day 7 post-vaccination

    Measured by Enzyme-Linked Immunosorbent Assay (ELISA)

  6. The level of neutralizing antibodies (NT50 and IC50, ng/mL) against the vaccine strain in serum at 28 days post-vaccination.

    Time frame: Day 28 post-vaccination

    Measured by Neutralization Assay

  7. The gene expression levels in PBMCs (Peripheral Blood Mononuclear Cells) at 7 days post-vaccination.

    Time frame: from baseline (pre-vaccination) to 7 days post-vaccination

    Measured by Bulk Ribonucleic Acid Sequencing.

  8. The gene expression levels in nasal mucosal cells at 7 days post-vaccination.

    Time frame: from baseline (pre-vaccination) to 7 days post-vaccination

    Measured by Bulk Ribonucleic Acid Sequencing.

  9. The gene expression levels in PBMCs (Peripheral Blood Mononuclear Cells) at 28 days post-vaccination.

    Time frame: Day 28 post-vaccination

    Measured by Bulk Ribonucleic Acid Sequencing.

  10. The gene expression levels in nasal mucosal cells at 28 days post-vaccination.

    Time frame: Day 28 post-vaccination

    Measured by Bulk Ribonucleic Acid Sequencing.

  11. The level of sIgA antibodies (AU/mL) against the vaccine strain in nasal secretions at 7 days post-vaccination.

    Time frame: Day 7 post-vaccination

    Measured by Enzyme-Linked Immunosorbent Assay (ELISA)

Other outcomes

  1. Changes in the abundance of intestinal microbiota compared with baseline (Exploratory).

    Time frame: Day 28 post-vaccination

    Measured by 16s RNA or metagenomic analysis

  2. Changes in the levels of fecal or serum metabolites compared with baseline (Exploratory)

    Time frame: Day 28 post-vaccination

    Ultra-High Performance Liquid Chromatography-Mass Spectrometry

Sponsors and collaborators

Lead sponsor

Jiangsu Province Centers for Disease Control and Prevention

Network

Registry information

Official study title

Mucosal and Systemic Immune Responses Induced by an Intranasal Influenza Live Attenuated Vaccine: A Single-Center, Open-Label, Single-Arm Clinical Study

Important dates

Study start
2025
Primary completion
2025
Study completion
2026
First posted
Nov 18, 2025
Registry last updated
Nov 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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