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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
PREVENTION
Masking
NONE
Enrollment
60
This vaccine is produced by Changchun BCHT Biotechnology Co.
Haizhou District Center for Disease Control and Prevention
Lianyungang, Jiangsu, China
The level of IgG antibodies (ng/mL) against the vaccine strain in serum at 28 days post-vaccination.
Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Time frame: Day 28 post-vaccination
The level of sIgA antibodies (AU/mL) against the vaccine strain in nasal secretions at 28 days post-vaccination.
Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Time frame: Day 28 post-vaccination
The levels of cytokines in serum at 7 days post-vaccination.
Measured by Meso Scale Discovery
Time frame: Day 7 post-vaccination
The levels of cytokines in nasal mucosal secretions at 7 days post-vaccination.
Measured by Meso Scale Discovery
Time frame: Day 7 post-vaccination
The levels of cytokines in serum at 28 days post-vaccination.
Measured by Meso Scale Discovery
Time frame: Day 28 post-vaccination
The levels of cytokines in nasal mucosal secretions at 28 days post-vaccination.
Measured by Meso Scale Discovery
Time frame: Day 28 post-vaccination
The level of IgG antibodies (ng/mL) against the vaccine strain in serum at 7 days post-vaccination.
Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Time frame: Day 7 post-vaccination
The level of neutralizing antibodies (NT50 and IC50, ng/mL) against the vaccine strain in serum at 28 days post-vaccination.
Measured by Neutralization Assay
Time frame: Day 28 post-vaccination
The gene expression levels in PBMCs (Peripheral Blood Mononuclear Cells) at 7 days post-vaccination.
Measured by Bulk Ribonucleic Acid Sequencing.
Time frame: from baseline (pre-vaccination) to 7 days post-vaccination
The gene expression levels in nasal mucosal cells at 7 days post-vaccination.
Measured by Bulk Ribonucleic Acid Sequencing.
Time frame: from baseline (pre-vaccination) to 7 days post-vaccination
The gene expression levels in PBMCs (Peripheral Blood Mononuclear Cells) at 28 days post-vaccination.
Measured by Bulk Ribonucleic Acid Sequencing.
Time frame: Day 28 post-vaccination
The gene expression levels in nasal mucosal cells at 28 days post-vaccination.
Measured by Bulk Ribonucleic Acid Sequencing.
Time frame: Day 28 post-vaccination
The level of sIgA antibodies (AU/mL) against the vaccine strain in nasal secretions at 7 days post-vaccination.
Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Time frame: Day 7 post-vaccination
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