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ChikungunyaPhase 3NCT04650399

A Multicenter Study to Evaluate Safety and Immunogenicity of a Live-attenuated Chikungunya Vaccine in Adolescents

A Phase 3 study testing Active in people with Chikungunya, run by Butantan Institute at 10 sites in Brazil.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This was a prospective, randomized, double-blinded, multicenter, pivotal study evaluating the full dose of VLA1553 (1 x10E4 TCID50 per dose) in comparison to a placebo control. The dose of VLA1553 or control was administered as single vaccination on Day 1. Read more about this study

Who is it for?
Ages 12 to 17 yearsHealthy volunteers can take part
Conditions the study is for
Chikungunya
What is being tested?
Active
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
754 participants
Where
10 sitesBrazil
Study dates
14 Feb 2022to 16 Feb 2024
Phase
Phase 3
Are there results?
Yes, posted in the registrySummary in the doctors' view

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 12 to 17 years
  • All sexes
  • Healthy volunteers accepted
  • Child

Who may be able to join

  • male or female adolescents from the 12th birthday to the last day before the 18th birthday at the time of vaccination;
  • written informed consent by the subject's legal representative(s), and written informed assent of the subject;
  • generally healthy as determined by the Investigator's clinical judgement based on medical history, physical examination and screening laboratory tests;
  • seropositive for previous CHIKV exposure (i.e. IgM+/IgG+ or IgM-/IgG+) or seronegative (i.e. IgM-/IgG-) as screened by CHIKV-specific ELISA.
  • for women of childbearing potential:
  • negative serum or urine pregnancy test at screening and on Day 1.
  • practiced an adequate method of contraception during 30 days before screening
  • agreed to employ adequate birth control measures for the first three months post-vaccination (i.e. until Day 85).

Who cannot join

  • Was taking medication or other treatment for unresolved symptoms attributed to a previous CHIKV infection; or had participated in a clinical study involving an investigational CHIKV vaccine;
  • acute or recent infection;
  • tested positive for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg) or hepatitis C virus (HCV);
  • live virus vaccine within 28 days or inactivated vaccine within 14 days prior to vaccination in this study or planned to receive a vaccine within 28 days or 14 days after vaccination, respectively;
  • abnormal findings in any required study investigations (including medical history, physical examination, and clinical laboratory) considered clinically relevant by the Investigator which pose a risk for participation in the study;
  • medical history of or currently had acute or progressive, unstable or uncontrolled clinical conditions that posed a risk for participation in the study;
Show all 19Show fewer
  • history of immune-mediated or clinically relevant arthritis / arthralgia;
  • history of malignancy in the past 5 years other than squamous cell or basal cell skin cancer. If there had been surgical excision or treatment more than 5 years ago which was considered to have achieved a cure, the subject could be enrolled;
  • known or suspected defect of the immune system, such as subjects with congenital or acquired immunodeficiency, including infection with HIV, status post organ transplantation or immuno-suppressive therapy within 4 weeks prior to vaccination;
  • history of any vaccine related contraindicating event (e.g., anaphylaxis, allergy to components of the candidate vaccine, other known contraindications);
  • with clinical conditions representing a contraindication to intramuscular vaccination and blood draws;
  • pregnant or lactating at the time of enrollment;
  • received blood-derived products (e.g. plasma) within 90 days prior to vaccination in this study or planned to use blood products until Day 180 of the study;
  • rash, dermatological condition or tattoos that would, in the opinion of the Investigator, interfere with injection site reaction rating;
  • known or suspected problem with alcohol or drug abuse as determined by the Investigator;
  • any condition that, in the opinion of the Investigator, may compromise the subjects well-being, might interfere with evaluation of study endpoints, or would limit the subject's ability to complete the study;
  • committed to an institution (by virtue of an order issued either by the judicial or the administrative authorities);
  • participation in another clinical study involving an investigational medicinal product (IMP) or device within 30 days prior to study enrollment or was scheduled to participate in another clinical study involving an IMP, or device during the course of this trial;
  • member of the team conducting the trial or in a dependent relationship with one of the study 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.

Trial locations and contacts

10 sites in 1 country.

10 sites in 1 country

Brazil10 sites

  • Centro de Pesquisas Clínicas Universidade Federal Sergipe

    Aracaju, Sergipe, 49100-000

  • Centro de Pesquisa e Desenvolvimento de Fármacos (CPDF) - Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas

    Belo Horizonte, Minas Gerais, 31270-010

  • CECOR - Centro Oncológico de Roraima

    Boa Vista, Acre, 69304-015

  • Centro de Pesquisa Clínica da Faculdade de Medicina da Universidade Federal de Mato Grosso do Sul - UFMS

    Campo Grande, 79070-900

  • Núcleo de Medicina Tropical - Universidade Federal do Ceará

    Fortaleza, Ceará, 60020-181

  • Fundação de Medicina Tropical Dr. Heitor Vieira Dourado

    Manaus, Amazonas, 69040-000

  • Real Hospital Português de Beneficência em Pernambuco

    Recife, Pernambuco, 52010-075

  • Associação Obras Sociais Irmã Dulce / Centro de Pesquisa Clínica - CPEC

    Salvador, Estado de Bahia, 40415-180

  • Faculdade de Medicina de São José do Rio Preto - FAMERP

    São José do Rio Preto, São Paulo, 15090-000

  • Centro de Estudos do Instituto de Infectologia Emílio Ribas

    São Paulo, 01246-900

Other trials in Brazil

About this study

Official title: A Multicenter, Randomized, Controlled, Double Blinded Pivotal Study to Evaluate Safety and Immunogenicity of a Live-attenuated Chikungunya Virus Vaccine Candidate (VLA1553) in Adolescents Aged 12 Years to <18 Years

This was a prospective, randomized, double-blinded, multicenter, pivotal study evaluating the full dose of VLA1553 (1 x10E4 TCID50 per dose) in comparison to a placebo control. The dose of VLA1553 or control was administered as single vaccination on Day 1. Overall, approximately 750 male and female participants aged 12 years to <18 years were enrolled into the study. After completion of the trial, a Post Trial Access program was performed to offer the VLA1553 vaccine to all placebo recipients.

Read the detailed description

This was a prospective, double-blinded, multicenter, randomized, pivotal Phase 3 study comprising 754 participants aged 12 years to <18 years randomized in a 2:1 ratio to the live-attenuated CHIKV vaccine candidate (VLA1553) or placebo. The dose of lyophilized VLA1553 or placebo was administered as a single intramuscular vaccination. Subjects in this study were stratified by baseline serostatus. The primary objective of the study was to evaluate the immunogenicity and safety of the full dose of VLA1553 28 days following the single vaccination. Immunogenicity evaluations in the immunogenicity subset included the proportion of subjects with neutralizing CHIKV antibody titers above the seroresponse threshold. The surrogate of protection reasonably likely to predict clinical benefit has been established in non-human primate passive transfer studies using human sera from the Phase 1 study. Safety data collection and immunogenicity were assessed until Month 12.

Conditions
Chikungunya
Being tested
Active, Placebo
Medical subject headings
Chikungunya Fever

What participants receive

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

  • ActiveBiological

    Single intramuscular vaccination on Day 1 with VLA1553, a lyophilized live-attenuated Chikungunya vaccine candidate 1x10E4 TCID50 per dose (0.5 mL)

  • PlaceboBiological

    Single intramuscular vaccination on Day 1 with Phosphate-Buffered Saline (PBS) as placebo (0.5 mL)

Study groups in NCT04650399
Study groupRoleWhat they receive
ActiveExperimentalVLA1553
Receives: Biological: Active
PlaceboPlacebo comparatorPlacebo
Receives: Biological: Placebo

What is being measured

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

  1. Seroprotection

    Percentage of subjects with a seroprotective CHIKV antibody level determined as µPRNT50>= 150 (Micro Plaque Reduction Neutralization Test 50%) for baseline negative subjects 28 days post-vaccination.

    Measured: On study Day 29,which is 28 days after single vaccination

Secondary outcomes (10)

  1. CHIKV-specific Antibody Titers as GMTs up to 1 Year

    Immune response as measured by CHIKV-specific neutralizing antibody titers on Day 1, Day 8, Day 29, Day 85, Day 180 (Month 6) and Day 365 (Month 12) post vaccination as determined by μPRNT

    Measured: On study Day 1, Day 8, Day 29, Day 85, Day 180 (Month 6) and Day 365 (Month 12) post vaccination

  2. Seroprotection up to 1 Year

    Percentage of subjects with seroprotective levels defined as μPRNT50 ≥ 150 for μPRNT baseline negative subjects on Day 8, Day 85, Day 180 and Month 12 post-vaccination as determined by μPRNT.

    Measured: On the study Day 8, Day 85, Day 180, and Day 365 (Month 12) after vaccination

  3. Seroconversion up to 1 Year Defined as > 4-fold Increase of μPRNT50 Compared to Baseline

    Percentage of subjects with seroconversion defined as > 4-fold increase of μPRNT50 compared to baseline at Day 29, Month 6 and Month 12 as determined by μPRNT assay

    Measured: On study Day 29, Day 180 and Month 12 after vaccination

  4. Fold Change in Neutralizing Antibodies Compared to Baseline

    Fold change of CHIKV-specific neutralizing antibody titers determined by μPRNT assay at Days 8, 29, 85, 180 and at Month 12 post-vaccination as compared to baseline

    Measured: On study Day 8, 29, 85, 180 and Month 12 after vaccination

  5. X-fold Change in Neutralizing Antibody Titers at Month 12 Compared to Baseline

    Percentage of subjects reaching an at least 4-fold, 8-fold, 16-fold or 64-fold change in CHIKV-specific neutralizing antibody titer compared to baseline as measured by μPRNT assay

    Measured: 365 days (12 months) after vaccination

  6. Immunogenicity (GMT) Per Baseline Serostatus

    CHIKV-specific neutralizing antibodies, determined by μPRNT assay at Days 1, 8, 29, 85, 180, and Month 12 post-vaccination stratified by μPRNT baseline serostatus.

    Measured: On study Day 1, 8, 29, 85, 180 and Month 12 after vaccination

  7. Number of Participants With Unsolicited Adverse Events

    Frequency of unsolicited AEs at Day 29 and Day 180 (6 months) post-vaccination

    Measured: On study Day 29 and Day 180 after vaccination

  8. Number of Participants With Solicited Adverse Events

    Frequency of solicited injection site and systemic adverse events within ten days post-vaccination

    Measured: up to 10 days after vaccination

  9. Number of Participants With Adverse Event of Special Interest

    Frequency of any Adverse Event of Special Interest:

    The following cluster of symptoms with or without remissions or exacerbations received particular consideration and were defined as early onset AESI:

    1. Fever (≥37.8°C measured axillary); and
    2. Acute (poly)arthralgia/arthritis, myalgia, neurological symptoms (e.g., meningoencephalitis, acute encephalitis, headache, seizures), retinitis/uveitis; or one or more of the following signs and symptoms: macular to maculopapular rash (sometimes with cutaneous pruritus (foot plant)), pigmentary changes, bullous rash/skin blistering, purpura and ecchymosis; and
    3. Onset of symptoms 2 to 21 days after vaccination (i.e., Day 3 to Day 22); and
    4. Duration of event ≥3 days, Onset of symptoms 22 days post vaccination or later (Day 23 - study end) was defined as late onset AESI.

    Measured: until 365 days (12 months) after vaccination

  10. Number of Participants With Serious Adverse Events

    Frequency and relatedness of any Serious Adverse Event (SAE) during the entire study period

    Measured: until 365 days (12 months) after vaccination

Timeline

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

  1. First posted2 Dec 2020
  2. Study start14 Feb 2022
  3. Primary completion14 Mar 2023
  4. Study completion16 Feb 2024

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
Double blind
Who is masked
Participant, Investigator
Enrolment
754 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04650399
Sponsor's protocol ID
VLA1553-321
Status last verified
Jun 2026
First submitted
25 Nov 2020
Last updated
4 Jun 2026
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Publications

  • Buerger V, Pfeiffer A, Schoengrundner P, Seebacher J, Hochreiter R, Kosulin K, Zoihsl O, Weisova P, Mader R, Loch AP, Morandi E Jr, Nogueira ML, de Brito CAA, Croda J, Teixeira MM, Coelho IC, Gurgel R, da Fonseca AJ, de Lacerda MVG, Moreira ED Jr, Veiga APR, Eder-Lingelbach S, Jaramillo JC. Safety and immunogenicity of a live-attenuated chikungunya virus vaccine in adolescents: final results from a 12-month, double-blind, randomised, placebo-controlled, phase 3 trial in endemic areas of Brazil. Lancet Infect Dis. 2026 Apr;26(4):417-428. doi: 10.1016/S1473-3099(25)00631-0. Epub 2025 Dec 8.

    PubMed 41380703

  • Buerger V, Hadl S, Schneider M, Schaden M, Hochreiter R, Bitzer A, Kosulin K, Mader R, Zoihsl O, Pfeiffer A, Loch AP, Morandi E Jr, Nogueira ML, de Brito CAA, Croda J, Teixeira MM, Coelho IC, Gurgel R, da Fonseca AJ, de Lacerda MVG, Moreira ED Jr, Veiga APR, Dubischar K, Wressnigg N, Eder-Lingelbach S, Jaramillo JC. Safety and immunogenicity of a live-attenuated chikungunya virus vaccine in endemic areas of Brazil: interim results of a double-blind, randomised, placebo-controlled phase 3 trial in adolescents. Lancet Infect Dis. 2025 Jan;25(1):114-125. doi: 10.1016/S1473-3099(24)00458-4. Epub 2024 Sep 5.

    PubMed 39243794

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Active in people with Chikungunya, run by Butantan Institute at 10 sites in Brazil.

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 8 inclusion and 19 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: finished, as of the sponsor's last update on 4 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 10 sites in Brazil. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. 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?

Yes. Results are posted in the registry (first posted 4 Jun 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Seroprotection (time frame: On study Day 29,which is 28 days after single vaccination). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04650399, which also lists 2 linked publications.

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 4 Jun 2026.

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