Chikungunya Virus InfectionNCT07254702
Prospective Safety Cohort Study After VLA1553 Vaccination in Municipalities Selected for Participation in the VLA1553 Pilot Vaccination Strategy in Brazil
An observational study of Chikungunya Virus Infection, run by Valneva Austria GmbH at 3 sites in Brazil.
Trial summary
This is an observational study with primary data collection, which will combine a prospective safety cohort study and an SCRI study. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy 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
- 5,000 participants
- Where
- 3 sitesBrazil
- Study dates
- 2 Feb 2026to 28 Feb 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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: This study will collect data from approximately 5,000 individuals who received VLA1553, as per label, as part of the pilot vaccination strategy in selected municipalities in Brazil.
Who may be able to join
- Male or female participants who received a single dose of VLA1553 at a vaccination unit while participating in the pilot vaccination strategy.
- Individuals that are target for the pilot vaccination strategy at the time of vaccination.
- Individuals understanding and being able to comply with all scheduled follow-up calls/contacts and study procedures.
- Have given informed consent/assent prior to entering the study.
Who cannot join
- Individuals who have received investigational products within the 30 days prior to VLA1553 vaccination, or individuals who have received VLA1553/IXCHIQ previously or any authorized or approved CHIKV vaccine.
- Individuals who are not expected to remain available for the study follow-up for the next 24 weeks after vaccination.
- Pregnant women: women exposed to VLA1553 anytime during their pregnancy or within 30 days preceding their last menstrual period will be invited to participate in a separate pregnancy surveillance study (study identifier VLA1553-403).
Trial locations and contacts
3 sites in 1 country.
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
About this study
Official title: Prospective Safety Cohort Study VLA1553-406
This is an observational study with primary data collection, which will combine a prospective safety cohort study and an SCRI study.
Read the detailed description
This prospective safety cohort study will be conducted in selected Brazilian municipalities participating in a pilot vaccination strategy. A total of 5,000 participants will be recruited. The primary objective is to estimate the incidence rates of a predefined set of AEs which constitute safety concerns. The secondary objectives are to measure the relative risk associated with VLA1553 administration for a predefined set of AEs which constitute safety concerns, and to assess the frequency of occurrence of any collected AE which are medically attended or meet the criteria of seriousness This study also aims to investigate VLA1553's safety in underrepresented populations by collecting all AEs, not just AEs which constitute safety concerns.
- 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 will start along with this observational study.
What is being measured
The primary outcome is the main question the study is designed to answer.
To estimate the incidence rates of a predefined set of AEs which constitute safety concerns according to the VLA1553 Risk Management Plan following the administration of the live-attenuated VLA1553 vaccine
For each safety concern, the risk windows after VLA1553 administration are defined as:
- 30 days for Chikungunya-like adverse reactions;
- 60 days for cardiac events, choosing a more conservative window than the 42 days suggested by the Brighton Collaboration recommendations on myocarditis;
- 60 days for arthritis to account for late-onset or potentially immune-mediated cases
Measured: From enrollment until Day 60
Secondary outcomes (2)
To measure the relative risk associated with VLA1553 administration for a predefined set of AEs which constitute safety concerns as per the VLA1553 Risk Management Plan for those AEs that have a defined risk window following vaccination.
Measured: From enrollment until Day 120
To assess the frequency of occurrence of predefined AEs which are medically attended or meet the criteria of seriousness.
- Frequency of occurrence of predefined chronic chikungunya-like adverse reactions;
- frequency of predefined SAEs;
- frequency of occurrence of arthralgia;
- frequency of occurrence of prolonged arthralgia;
- frequency of predefined CHIKV infection symptoms;
- frequency of occurrence of predefined chronic CHIKV infection symptoms
Measured: From enrollment until Month 6
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Nov 2025
- Study start2 Feb 2026
- Primary completion31 Oct 2026 (estimated)
- Study completion28 Feb 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
- Cohort
- Time perspective
- Prospective
- Enrolment
- 5,000 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Valneva Austria GmbH
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Butantan Foundation, Coalition for Epidemic Preparedness Innovations
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07254702
- Sponsor's protocol ID
- VLA1553-406
- Status last verified
- Jul 2026
- First submitted
- 19 Nov 2025
- Last updated
- 21 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided