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Chikungunya Virus InfectionPhase 3NCT07133178

A Trial to Evaluate the Safety and Immunogenicity of VLA1553 in Healthy Children

A Phase 3 study testing VLA1553 in people with Chikungunya Virus Infection, run by Valneva Austria GmbH.

Withdrawn

Withdrawn. The study stopped before anyone enrolled.

Official record
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Trial summary

VLA1553-322 is a multicenter, prospective, randomized, double-blind, phase 3 clinical trial evaluating VLA1553 in comparison to a comparator (Nimenrix®) for each stratum (age group). Read more about this study

Who is it for?
Ages 1 year to 11 yearsHealthy volunteers can take part
Conditions the study is for
Chikungunya Virus Infection
What is being tested?
VLA1553
Could I receive a placebo?
No, everyone receives an active treatment
How many people
0 participants
Where
No sites listed yet
Study dates
6 Feb 2026to Nov 2027
Phase
Phase 3
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 1 year to 11 years
  • All sexes
  • Healthy volunteers accepted
  • Child

Who may be able to join

  • Male or female healthy children aged 7 to 11 years for Stratum A, 3 to 6 years for Stratum B and 1 to 2 years for Stratum C at the time of obtaining participant informed consent / assent;
  • Written informed consent by the participant's parent(s) / Legally Acceptable Representative(s) (LAR(s), according to local requirements, and written informed assent of the participant, if applicable;
  • Participant is generally healthy as determined by the Investigator's clinical judgement based on medical history, physical examination and screening laboratory tests;
  • Participants in Stratum C (1 to 2 years) must be within the normal WHO growth and weight ranges for their age.
  • Participant is seropositive for previous CHIKV exposure (i.e. IgM+ / IgG+ or IgM- / IgG+) or seronegative (i.e. IgM- / IgG-);
  • If participant is of childbearing potential (e.g. after onset of menarche) and if involved in activities that could result in pregnancy:
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  • Female participant has a negative pregnancy test (in accordance with local regulations) at Screening (Visit 0) and Day 1 (Visit 1), respectively;
  • Female participant has practiced an adequate method of contraception during at least the 30 days before Screening (Visit 0) and during the Screening period;
  • Female/ male participant agrees to employ adequate birth control measures ) for the first three months post-vaccination (i.e. until Day 85, Visit 5).

Who cannot join

  • Participant who is anti-CHIKV IgM+ / IgG- does not qualify for participation in this trial.
  • Participant is taking medication or other treatment for unresolved symptoms attributed to a previous CHIKV infection; or has participated in a clinical trial involving an investigational CHIKV vaccine;
  • Participant has an acute or recent infection and who is not symptom-free in the week prior to both the Screening visit (Visit 0) and Visit 1;
  • Participant has received another live virus vaccine within 28 days or inactivated / other vaccine within 14 days prior to vaccination in this trial or plans to receive a live virus vaccine within 28 days or inactivated vaccine / other within 14 days after vaccination; Whenever possible, standard of care vaccinations should be planned with the trial VLA1553 administration in mind.
  • Participant has an ongoing medical history of or currently has acute or progressive, unstable, controlled or uncontrolled clinical condition (e.g., cardiovascular, respiratory, neurologic, psychiatric, or rheumatologic conditions) that poses a risk for participation in the trial, based on the Investigators clinical judgement. Examples include individuals with controlled, poorly controlled or unstable disease, ongoing suspected or active inflammation, or poor compliance with pharmacologic treatment, or presence of high-risk comorbidities (e.g., significant cardiopulmonary disease);
  • Participant has abnormal findings in any required trial investigations (including medical history, physical examination, and clinical laboratory) considered clinically relevant by the Investigator which pose a risk for participation in the trial based on his / her judgement;
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  • Participant has a history of immune-mediated or clinically relevant arthritis / arthralgia;
  • The participant, their parent(s) / LAR(s) or siblings have a known HIV, hepatitis B or hepatitis C infection;
  • Participant has a history of malignancy;
  • Participant has a known or suspected defect of the immune system that can be expected to influence the immune response to the vaccine, such as participants with congenital or acquired immunodeficiency, including infection with HIV, status post organ transplantation or immuno-suppressive therapy within 4 weeks prior to Visit 1. Immuno-suppressive therapy is defined as administration of chronic (longer than 14 days) prednisone or equivalent ≥0.05 mg / kg / day within 4 weeks prior to trial entry, radiation therapy or immunosuppressive cytotoxic drugs / monoclonal antibodies in the previous 3 years; topical and inhaled steroids are allowed.
  • Participant has a history of any vaccine related contraindicating event (e.g., anaphylaxis, allergy to components of VLA1553 or Nimenrix®, or other known contraindications including febrile convulsions);
  • Participant presents with clinical conditions representing severe bleeding disorders and medications interfering with blood clotting;
  • Participant is pregnant (positive pregnancy test - in accordance with local regulations - at Screening or Visit 1, respectively) or is lactating at the time of enrollment or, for participants involved in activities potentially leading to pregnancy:
  • female participants on unreliable contraception after onset of menarche
  • male participant does not agree to employ adequate birth control measures during the first three months:
  • Participant received blood-derived products (e.g. plasma) within 180 days prior to vaccination in this trial;
  • Participant has a rash, dermatological condition or tattoos that would, in the opinion of the Investigator, interfere with injection site AE measurement and rating;
  • Participant has participated in another clinical trial involving an investigational medicinal product (IMP) or device within 30 days prior to vaccination or is scheduled to participate in another clinical trial involving an IMP, or device at any time during this trial;
  • Participant has any condition that, in the opinion of the Investigator, may compromise the participants well-being, might interfere with evaluation of trial endpoints, or would limit the participant's ability to complete the trial;
  • Participant / Participant's parent(s) / LAR(s) is / are 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, parent(s) / LAR(s) as well as employees of the Investigator or site personnel conducting the trial;
  • Participant has received the comparator (Nimenrix® or any equivalent meningococcal conjugate vaccine covering serogroups A, C, W-135, and Y) prior to the trial.

About this study

Official title: A Multicenter, Randomized, Controlled, Double-blind Pivotal Phase 3 Trial to Evaluate the Safety and Immunogenicity of a Live-attenuated Chikungunya Virus Vaccine (VLA1553) in Healthy Children Aged 1 to 11 Years

VLA1553-322 is a multicenter, prospective, randomized, double-blind, phase 3 clinical trial evaluating VLA1553 in comparison to a comparator (Nimenrix®) for each stratum (age group). At least 3,000 male and female healthy children aged 1 to 11 years will be enrolled and randomized 3:1 to either VLA1553 (n=2,250) or comparator (Nimenrix®) (n=750).

Read the detailed description

This is a multicenter, prospective, randomized, double-blind, Phase 3 clinical trial evaluating VLA1553 in comparison to a comparator (Nimenrix®) in healthy children aged 1 to 11 years after a single vaccination in endemic countries.

The overall trial duration (First Participant In - Last Participant Out) is estimated to be approximately 22 months. Individual participation is approximately 13 months (immunogenicity subset) from ICF signature to trial completion, unless prematurely discontinued.

At least 3,000 male and female healthy children aged 1 to 11 years will be enrolled and randomized 3:1 to either VLA1553 (n=2,250) or comparator (Nimenrix®) (n=750). These children will be screened for evidence of previous CHIKV exposure.

The trial will be conducted in Latin America and / or Southeast Asia to ensure a diverse participant population and broad applicability of results. An independent Data and Safety Monitoring Board (DSMB) will oversee participant safety, review interim data, and provide recommendations on the trial's continuation. Additionally, a Valneva internal Safety Review Committee (SRC) will review safety data according to their pertinent SRC Charter.

The trial is divided into three sequential parts with predefined timepoints: Part A (Day 29, Visit 4), Part B (Month 6, Visit 6) and Part C (Month 12, Visit 7). Analyses for each part will be conducted independently after the last participant completes the respective visit, with Part A analyzed after Day 29, Part B after Month 6, and Part C after Month 12.

Being tested
VLA1553, Control
Medical subject headings
Chikungunya Fever

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • VLA1553Biological

    Single intramuscular vaccination on Day 1 with VLA1553 full dose, a lyophilized live-attenuated Chikungunya vaccine

  • ControlBiological

    Single intramuscular vaccination on Day 1 with Nimenrix (Men ACWY vaccine), a conjugate vaccine indicated for the active immunization

Study groups in NCT07133178
Study groupRoleWhat they receive
VLA1553ExperimentalVLA1553
Receives: Biological: VLA1553
ControlActive comparatorNimenrix will be used as Comparator
Receives: Biological: Control

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. The proportion of participants with a seroresponse as defined by μPRNT50 for baseline negative participants

    Measured: 28 days post-vaccination

Secondary outcomes (13)
  1. Immune response as measured by CHIKV-specific neutralizing antibody titers as determined by μPRNT assay

    Measured: on Day 1, Day 15, Day 29, Day 85, Day 180, and Month 12 (Day 365)

  2. Proportion of participants with seroresponse as determined by μPRNT assay

    Measured: on Day 15, Day 29, Day 85, Day 180 and Month 12 (Day 365)

  3. Proportion of participants with seroconversion as compared to baseline as determined by μPRNT assay

    Measured: on Day 15, Day 29, Day 85, Day 180 and Month 12 (Day 365)

  4. Fold increase of CHIKV-specific neutralizing antibody titers determined by μPRNT assay as compared to baseline

    Measured: on Day 15, Day 29, Day 85, Day 180 and Month 12 (Day 365)

  5. Proportion of participants reaching an at least 4-fold, 8-fold, 16-fold, or 64-fold increase in CHIKV-specific neutralizing antibody titers compared to baseline as measured by μPRNT assay

    Measured: on Day 15, Day 29, Day 85, Day 180 and Month 12 (Day 365)

  6. Antibody titers, seroresponse, seroconversion and fold increases for CHIKV-specific neutralizing antibodies, determined by μPRNT assay stratified by CHIKV baseline serostatus (based on μPRNT) and age stratum

    Measured: at Day 15, Day 29, Day 85, Day 180 and Month 12 (Day 365)

  7. Frequency and severity of any Adverse Event (AE), stratified by CHIKV baseline serostatus and age stratum

    Measured: until Day 29

  8. Frequency and severity of unsolicited Adverse Events (AE), stratified by CHIKV baseline serostatus and age stratum

    Measured: until Day 180 and Month 12

  9. Frequency and severity of solicited injection site and systemic Adverse Event (AE), stratified by CHIKV baseline serostatus and age stratum

    Measured: within 14 days post-vaccination

  10. Frequency and relatedness of any Serious Adverse Event (SAE), stratified by CHIKV baseline serostatus and age stratum

    Measured: during entire trial period

  11. Frequency and severity of any adverse event of special interest (AESI), stratified by CHIKV baseline serostatus and age stratum

    Measured: starting within 2 to 21 days post-vaccination

  12. Frequency and severity of any late onset adverse event of special interest (AESI), stratified by CHIKV baseline serostatus and age stratum

    Measured: during the entire trial starting 22 days post-vaccination

  13. Frequency and severity of adverse event of special interest (AESI) (regulatory agency definition), stratified by CHIKV baseline serostatus and age stratum

    Measured: with an onset within 30 days post-vaccination

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted20 Aug 2025
  2. Study start6 Feb 2026 (estimated)
  3. Primary completionDec 2026 (estimated)
  4. Study completionNov 2027 (estimated)

Why it stopped: No participant recruited; trial initiation postponed to an unspecified future time while Valneva assesses potential pathways to address regulatory requests. Evaluation is ongoing to ensure alignment with regulatory expectations and obligations.

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
0 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07133178
Sponsor's protocol ID
VLA1553-322
Status last verified
Dec 2025
First submitted
13 Aug 2025
Last updated
31 Dec 2025
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: 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.

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing VLA1553 in people with Chikungunya Virus Infection, run by Valneva Austria GmbH.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 9 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: withdrawn, as of the sponsor's last update on 31 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study was withdrawn before enrolling participants, so there are no results.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

The proportion of participants with a seroresponse as defined by μPRNT50 for baseline negative participants (time frame: 28 days post-vaccination). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Dec 2025.

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