Characterisation of Dengue Vaccine-induced Specific Immunity in Vaccinees With and Without Prior Exposure to Flavivirus Infections or Vaccination

Recruiting

• Conditions: Dengue Vaccines
• Interventions: Drug: Qdenga

• Registration Number: NCT06776692
• Lead Sponsor: IRCCS Sacro Cuore Don Calabria di Negrar

Brief Summary

The goal of this observational study is to learn about the immunity induced by the Qdenga® vaccine in vaccinees.

Participants that will receive the Dengue vaccine as part of their routine before a travel will be asked to undergo a blood sample at the time of administration of the first dose (T0), 24-48 hours after the first dose (T1) of the vaccine, immediately before the second dose (T2 ) and one to two months after the second dose (T3). Possibly a further sample will be collected within 2 years.

Detailed Description

This is a non-profit, single-center, drug-based observational study whose primary objective is to characterize dengue-specific humoral and cellular immunity induced by the Qdenga® vaccine in vaccinees.

The study involves the enrollment of all pediatric subjects (age ≥ 4 years) and adults who present themselves at the DITM travel clinic for the administration of the Dengue vaccine; 402 patients are expected to be enrolled and will be asked to undergo a blood sample at the time of administration of the first dose (T0), 24-48 hours after the first dose (T1) of the vaccine, immediately before the second dose (T2 ) and one to two months after the second dose (T3). Possibly a further sample will be collected within 2 years (T4). The samples thus collected will be analyzed for the characterization of innate immunity, the characterization of cellular immunity and the characterization of the humoral response.

Study Timeline

• Study Start: 2024-07-10
• Study First Submitted: 2025-01-03
• Study First Submitted QC: 2025-01-14
• Study First Posted: 2025-01-15
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-16
• Last Update Posted: 2025-05-18
• Primary Completion: 2028-01
• Study Completion: 2028-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 402

Inclusion Criteria

• Subjects of both sexes presenting to the DITM to receive the anti-DENV vaccine whether or not they have had a history of prior DENV or other flaviviruses infection or a history of prior vaccination against other flaviviruses. These data will be recorded in the study CRF.
• Age >= 4 years.
• Signed informed consent.

Exclusion Criteria

• Age < 4 years.
• Absence of signed informed consent.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Patients	Qdenga	All pediatric and adult subjects attending the travel clinic of the DITM for the administration of Dengue vaccine.

Primary Outcome Measures

Name	Time	Method
Anti-DENV antibodies	BEFORE administration of the first dose (Time 0 = T0), immediately BEFORE the second dose (Time 2 = T2) of vaccine, and one to two months after the second dose (Time 3 = T3)	Anti-DENV antibodies quantities (IgG and IgM, continuous variables unity of measure: Antibody titre dilution) BEFORE administration of the first dose (T0), immediately BEFORE the second dose (T2) of vaccine, and one to two months after the second dose (T3)

Secondary Outcome Measures

Name	Time	Method
Innate immunity response	BEFORE administration of the first dose (T0), after 24-48h after the first dose (Time 1 = T1)	Type I and II IFN and IFN-inducible genes, specific cytokines and chemokines induced by Qdenga® vaccine (continuous variables: deltaCt mRNA expression and Optical Density (OD)) at T0 and T1
Cellular response	At the moment of the administration of the first dose (T0), immediately before the second dose (T2), and one to two months after the second dose (T3)	1. immunophenotype asset: results of the flow cytometry profiles (proportions of cells),; 2. specific T- and B-cells response to viral peptides: analysis results of T- and B-cells stimulation with DENV specific peptides (continuous variables, unity of measure: Optical Density (OD)) at T0, T2 and T3.
Quantitative and qualitative anti-DENV antibody response	At the moment of the administration of the first dose (T0), immediately before the second dose (T2), and one to two months after the second dose (T3)	1. anti-DENV antibodies quantities (IgG and IgM, continuous variables unity of measure: Antibody titre dilution) at T0, T2 and T3,; 2. Analysis results of neutralization assays against different DENV serotypes (continuous variables, unity of measure: TCID50/ml) at T0, T2 and T3,
Humoral response	At the moment of the administration of the first dose (T0), immediately before the second dose (T2), and one to two months after the second dose (T3)	1. Analysis results humoral response against different flaviviruses (IgG and IgM, continuous variables unity of measure: Antibody titre dilution) at T0, T2 and T3,; 2. Analysis results of DENV specific avidity assays (unity of measure: Index); 3. Previous infections with (y/n) or vaccinations against (y/n) other flaviviruses
Cell mediated response	At the moment of the administration of the first dose (T0), immediately before the second dose (T2), and one to two months after the second dose (T3)	Analysis results cell mediated response against different flaviviruses (continuous variables, unity of measure: Optical Density (OD)) at T0, T2 and T3.

Trial Locations

Locations (1)

IRCCS Sacro Cuore Don Calabria; 🇮🇹 Negrar, VR, Italy