Antibody Persistence And Long Term Safety Of A Chikungunya Virus Vaccine (VLA1553)

December 22, 2025 updated by: Valneva Austria GmbH

An Open-Label, Single Arm Trial To Evaluate Antibody Persistence And Long Term Safety Of A Live-Attenuated Chikungunya Virus Vaccine (VLA1553) In Adults Aged 18 Years and Above

In this open-label Phase 3b, single arm trial, persistence of antibodies and long term safety will be evaluated in up to 375 participants rolled over from trial VLA1553-301 (NCT number: NCT04546724).

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

In this open-label Phase 3b, single arm trial, persistence of antibodies and long term safety in up to 375 participants rolled over from trial VLA1553-301 (NCT number: NCT04546724)

These participants will have annual follow-up visits at Months 12, 24, 36, 48, 60, 72, 84, 96, 108 and 120 after immunization. The primary objective of this trial will be to evaluate persistence of antibodies annually from 1 to 10 years after the single immunization with VLA1553. The secondary objective is to evaluate long-term safety 6 months to 2 years after the single immunization with VLA1553.

Study Type

Interventional

Enrollment (Actual)

363

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85020
        • Accelerated Enrollment Solutions (AES)
    • Florida
      • Hallandale, Florida, United States, 33090
        • Velocity Clinical Research
    • Illinois
      • Chicago, Illinois, United States, 60602
        • Accelerated Enrollment Solutions (AES)
    • Kentucky
      • Lexington, Kentucky, United States, 40509
        • Alliance for Multispecialty research (AMR)
    • Nebraska
      • Grand Island, Nebraska, United States, 68803
        • Velocity Clinical Research
      • Omaha, Nebraska, United States, 68134
        • Velocity Clinical Research
    • Tennessee
      • Knoxville, Tennessee, United States, 37920
        • Alliance for Multispecialty research (AMR)
    • Texas
      • Austin, Texas, United States, 78759
        • Velocity Clinical Research
    • Utah
      • West Jordan, Utah, United States, 84088
        • Velocity Clinical Research
    • Virginia
      • Norfolk, Virginia, United States, 23502
        • Allliance for Multispecialty Research (AMR)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Individual participated in the VLA1553-301 clinical trial;
  • Participant has an understanding of the trial and its procedures, agrees to its provisions, and voluntarily gives written informed consent prior to any trial-related procedures;
  • Participant had immunogenicity blood samples taken at baseline (Visit 1) and either Day 29 (Visit 3), Day 85 (Visit 4) or Day 180 (Visit 5) in Trial VLA1553-301 and was negative for neutralizing antibodies at baseline

Exclusion Criteria:

  • Participant presents with clinical conditions representing a contraindication to blood draws;
  • Participant has donated blood or use of blood products prior 30 days of immunogenicity sampling;
  • Participant has received an active drug with potential immunosuppressive action or investigational drug or device within a period of 30 days prior a trial visit;
  • Participant has a known or suspected problem with alcohol or drug abuse as determined by the Investigator;
  • Participant has any condition that, in the opinion of the Investigator, may compromise the participant's well-being, might interfere with evaluation of trial endpoints, or would limit the participant's ability to complete the trial;
  • Participant is committed to an institution (by virtue of an order issued either by the judicial or the administrative authorities);
  • Participant is a member of the team conducting the trial or in a dependent relationship with one of the trial team members. Dependent relationships include close relatives (i.e., children, partner/spouse, siblings, parents) as well as employees of the Investigator or site personnel conducting the trial.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: VLA1553
Biological: VLA1553
Trial participants previously vaccinated with VLA1553 in trial VLA1553-301 will be followed up for safety and immunogenicity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Proportion of participants with seroresponse levels post-vaccination. (defined as µPRNT50 ≥150)
Time Frame: until Year 10
until Year 10

Secondary Outcome Measures

Outcome Measure
Time Frame
Frequency of any Serious Adverse Event (SAE)
Time Frame: until Year 2
until Year 2
Relatedness of any Serious Adverse Event (SAE)
Time Frame: until Year 2
until Year 2
Immune response as measured by CHIKV-specific neutralizing antibody titers post-vaccination
Time Frame: until Year 10
until Year 10
Proportion of participants with seroconversion
Time Frame: until Year 10
until Year 10
Fold increase of CHIKV-specific neutralizing antibody titers post-vaccination as compared to baseline (i.e. at start of trial VLA1553-301)
Time Frame: until Year 10
until Year 10
Proportion of participants reaching an at least 4-fold, 8-fold, 16-fold or 64-fold increase in CHIKV-specific neutralizing antibody titer compared to baseline
Time Frame: until Year 10
until Year 10

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Valneva Austria GmbH

Investigators

  • Study Chair: Valneva Clinical Development, Valneva Austria GmbH

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 2, 2021

Primary Completion (Estimated)

December 1, 2025

Study Completion (Estimated)

May 1, 2031

Study Registration Dates

First Submitted

April 6, 2021

First Submitted That Met QC Criteria

April 8, 2021

First Posted (Actual)

April 9, 2021

Study Record Updates

Last Update Posted (Actual)

December 24, 2025

Last Update Submitted That Met QC Criteria

December 22, 2025

Last Verified

August 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • VLA1553-303

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

After trial completion, Valneva may provide access to individual de-identified participant data and related trial documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Trial Report (CTR)) upon request from qualified researchers, and subject to Valneva's review and approval.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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