Clinical study to identify factors that affect the immune response to yellow fever and dengue vaccines

Clinical study for the identification of factors influencing the immune response to yellow fever and dengue vaccines

Status

Recruiting

Phases

Unknown

Study type

Observational

Source

ISRCTN

Registry ID

ISRCTN66253408

Enrollment

400

Registered

2026-06-23

Start date

2025-07-01

Completion date

Unknown

Last updated

2026-07-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Investigation of the immune response to the yellow fever and dengue vaccines in healthy volunteers with or without prior orthoflavivirus immunity Infections and Infestations

Interventions

This is an investigation of the immune response to the yellow fever (YF17D) and dengue (QDENGA) vaccines in healthy adult volunteers with or without prior orthoflavivirus immunity in the Veneto Region

Eligibility

Sex/Gender

All

Age

18 Years to 60 Years

Inclusion criteria

Inclusion criteria: 1. Male or female individuals aged between 18 and 60 years 2. Healthy individuals, free from acute infections or chronic diseases 3. Willingness to provide written informed consent after being adequately informed about the risks and benefits of the study 4. Availability to participate in at least two study-scheduled visits

Exclusion criteria

Exclusion criteria: 1. Hypersensitivity to vaccine components (active ingredients or excipients) for YF17D and QDENGA vaccines, including egg/chicken proteins for YF17D. 2. Severe hypersensitivity reactions to previous yellow fever or dengue vaccines. 3. Immunodeficiency (congenital, idiopathic, or treatment-induced). 4. History of thymic dysfunction. 5. Symptomatic HIV infection or asymptomatic HIV with compromised immune response. 6. Moderate to severe illness or acute disease. 7. Pregnancy or breastfeeding. 8. Body temperature >38°C or acute illness on study entry day. 9. Autoimmune diseases or immunosuppressive therapy within 6 months. 10. Corticosteroid therapy >2 weeks in the past 3 months. 11. Known allergic or anaphylactic reactions. 12. Use of unregistered drugs or participation in other clinical trials. 13. Recent (<3 months) or planned administration of immunoglobulins or blood products. 14. Non-compliance with study objectives or protocol (investigator's opinion). 15. Anticipated absence from the study center during the study period.

Design outcomes

Primary

Measure	Time frame
YF17D-binding (IgM and IgG) and neutralizing antibody titres measured by enzyme immunoassay (EIA) and microneutralization assays; evaluation of cell-mediated response using flow-cytometry, analysis of viral replication kinetics using quantitative PCR (qPCR), and study of predictive biomarkers for adaptive immune response efficacy by cytokine profiling by multiplex assays on Luminex platform. Analyses will be performed at baseline and during follow-ups at days 14 and 28 post-vaccination, and one year after vaccination.	—

Measure

Time frame

YF17D-binding (IgM and IgG) and neutralizing antibody titres measured by enzyme immunoassay (EIA) and microneutralization assays; evaluation of cell-mediated response using flow-cytometry, analysis of viral replication kinetics using quantitative PCR (qPCR), and study of predictive biomarkers for adaptive immune response efficacy by cytokine profiling by multiplex assays on Luminex platform. Analyses will be performed at baseline and during follow-ups at days 14 and 28 post-vaccination, and one year after vaccination.

—

Secondary

Measure	Time frame
There are no secondary outcome measures	—

Countries

Italy

Contacts

Public ContactLuisa Barzon

luisa.barzon@unipd.it+390498218946

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Jul 23, 2026