Chikungunya Virus InfectionNCT07347002

Observational Study to Assess the Effectiveness of VLA1553 Vaccine in Preventing Chikungunya During a Pilot Vaccination Strategy in Brazil

An observational study of Chikungunya Virus Infection, run by Valneva Austria GmbH at 3 sites in Brazil.

Enrolling by invitation

Enrolling by invitation. The study team selects and invites participants, usually from an existing group of patients.

Sites and contacts

Official record

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Trial summary

This is an observational, non-interventional, test-negative case-control (TNCC) study to estimate the vaccine effectiveness of VLA1553 against Chikungunya virus in a real-world setting. Read more about this study

Who is it for?: Ages 18 to 59 yearsHealthy volunteers can take part
Conditions the study is for: Chikungunya Virus Infection
What is being tested?: Live-attenuated CHIKV vaccine VLA1553
Type of treatment: Vaccines
How many people: 1,200 participants
Where: 3 sitesBrazil
Study dates: 2 Feb 2026to 31 Dec 2027
Phase: Observational

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 18 to 59 years
All sexes
Healthy volunteers accepted
Adult

Study population: Residents of the selected areas, within the age limits approved for the PVS, presenting at the health care facilities during the study period.

Who may be able to join

Have a CHIKV RT-PCR result registered from a municipality where the pilot vaccination strategy is implemented and is in scope of the VLA1553-402 study;
Are in an eligible age-group to receive the VLA1553 vaccine;
Have been notified in SINAN as a suspected case for CHIK or Dengue surveillance during the study period;
Have a sample registered in GAL that is collected within 0-5 days following the onset of CHIKV-like symptoms and is tested for CHIKV using RT-PCR;
Have complete data in the Brazilian MoH databases (SINAN and GAL) on age, sex, municipality of residence, sample collection date, and date of symptom onset and the healthcare facilities where the suspected case was reported.

Who cannot join

Have inconclusive RT-PCR result for CHIKV;
Have a detectable vaccine virus identified via sequencing;
For vaccinated and CHIV RT-PCR positive individuals, have no valid sequencing result available for RT-PCR positive samples collected within 30 days post-vaccination;
Have the first CHIKV-like symptom onset less than 14 days from date of vaccination.

Trial locations and contacts

3 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Brazil3 sites

Universidade Federal de Minas Gerais, CT Terapias Avançadas e Inovadoras
Belo Horizonte, Minas Gerais, 31270-901
Centro de Pesquisas Clínicas Universidade Federal Sergipe, Hospital e Maternidade São João de Deus
Laranjeiras, Sergipe, 49060-025
Fundação Faculdade Regional De Medicina De São José Do Rio Preto
São Pedro, São Paulo, 15090-000

Other trials in Brazil

About this study

Official title: A Test-Negative Case-control Study to Evaluate the Effectiveness of VLA1553 Against Chikungunya Virus Disease During a Pilot Vaccination Strategy in Brazil

This is an observational, non-interventional, test-negative case-control (TNCC) study to estimate the vaccine effectiveness of VLA1553 against Chikungunya virus in a real-world setting.

Read the detailed description

The objective of this study is to evaluate the effectiveness of vaccination with VLA1553 in the prevention of laboratory-confirmed symptomatic cases of CHIK after a single dose of VLA1553 administered as part of a pilot vaccination strategy following licensure in Brazil.

The study will commence following the implementation of the pilot vaccination strategy in selected municipalities. Data for the analyses will be obtained from official Brazilian Ministry of Health surveillance systems, specifically the GAL (Laboratory Environment Management System), SINAN (Notifiable Diseases Information System), and Si-PNI (National Immunization Program Information System).

Conditions: Chikungunya Virus Infection
Being tested: Live-attenuated CHIKV vaccine VLA1553
Medical subject headings: Chikungunya Fever

What participants receive

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

Live-attenuated CHIKV vaccine VLA1553Biological
Non-interventional study: VLA1553 is used in the pilot vaccination strategy which is linked to this observational study.

Study groups in NCT07347002
Study group	Role	What they receive
Cases: Test-positive for Chikungunya virus		Not described Receives: Biological: Live-attenuated CHIKV vaccine VLA1553
Controls: Test-negative for Chikungunya virus		Not described Receives: Biological: Live-attenuated CHIKV vaccine VLA1553

What is being measured

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

Detection of CHIKV in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated study individuals with CHIKV-like symptoms confirmed by reverse transcriptase polymerase chain reaction (RT-PCR).
Measured: Study start through study completion, an average of 23 months

Secondary outcomes (1)

Detection of CHIKV in VLA1553-vaccinated (≥14 days after vaccination) and unvaccinated study individuals ≥50 years of age with CHIKV-like symptoms confirmed by RT-PCR.
Measured: Study start through study completion, an average of 23 months

Timeline

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

2 Feb 202631 Dec 2027

First posted16 Jan 2026
Study start2 Feb 2026
Primary completion31 Dec 2027 (estimated)
Study completion31 Dec 2027 (estimated)

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Other trials for Chikungunya Virus InfectionStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

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

Study design

Study type: Observational
Observational model: Case-control
Time perspective: Retrospective
Enrolment: 1,200 participants (estimated)

IDs, dates and publications

ClinicalTrials.gov ID: NCT07347002
Sponsor's protocol ID: VLA1553-402
Status last verified: Jul 2026
First submitted: 4 Dec 2025
Last updated: 17 Jul 2026
Results posted: No
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: Undecided

Interested in taking part?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See sites and contacts

RecruitingPhase 4
Real-world Effectiveness, Safety & Immunogenicity of Chikungunya Vaccination: Ambispective Study in Reunion & French Guiana
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Against Chikungunya Virus and Neonatal Infection
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Active, not recruitingPhase 3
Long-term Follow-up Study to Evaluate Safety and Immunogenicity of CHIKV VLP Single or Booster Vaccination
Chikungunya Virus Infection
Active, not recruitingObservational study
Prospective Safety Cohort Study After VLA1553 Vaccination in Municipalities Selected for Participation in the VLA1553 Pilot Vaccination Strategy in Brazil
Chikungunya Virus Infection
Enrolling by invitationObservational study
VLA1553-403 Pregnancy Surveillance Study
Chikungunya Virus Infection

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