Prospective Safety Cohort Study After VLA1553 Vaccination in Municipalities Selected for Participation in the VLA1553 Pilot Vaccination Strategy in Brazil

NCT07254702 | Enrolling By Invitation DMC

• 1 other identifier: VLA1553-406
• Study Type: observational
• Target: 5,000
• Locations: 1 country
• Sites: 4

Brief Summary

This is an observational study with primary data collection, which will combine a prospective safety cohort study and an SCRI study.

Conditions

Chikungunya Virus Infection

Outcome Measures

Primary Outcomes (1)

• 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: 1. 30 days for Chikungunya-like adverse reactions; 2. 60 days for cardiac events, choosing a more conservative window than the 42 days suggested by the Brighton Collaboration recommendations on myocarditis; 3. 60 days for arthritis to account for late-onset or potentially immune-mediated cases

  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.

  From enrollment until Day 120

• To assess the frequency of occurrence of predefined AEs which are medically attended or meet the criteria of seriousness.

  From enrollment until Month 6

Other Outcomes (2)

• To assess the frequency of occurrence of AEs (not exclusively those of safety concern) following VLA1553 vaccination when co-administered or concomitantly administered with other vaccines.

  From enrollment until Month 6

• To assess the frequency of occurrence of AEs (not exclusively those of safety concern) in populations underrepresented or excluded in clinical trials with VLA1553.

  From enrollment until Month 6

Interventions

Live-attenuated CHIKV vaccine VLA1553 BIOLOGICAL

Non-interventional study: VLA1553 is used in the pilot vaccination strategy which will start along with this observational study.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

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.

You may qualify if:

• 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.

You may not qualify if:

• 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 residing outside of the study municipalities or are not expected to remain in the study municipalities 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).

Sponsors & Collaborators

• Butantan Foundation: collaborator
• Valneva Austria GmbH: lead
• Coalition for Epidemic Preparedness Innovations: collaborator

Study Sites (4)

Universidade Federal Do Ceará

Fortaleza, Ceará, 60430-160, Brazil

Location

Universidade Federal de Minas Gerais, CT Terapias Avançadas e Inovadoras

Belo Horizonte, Minas Gerais, 31270-901, Brazil

Location

Centro de Pesquisas Clínicas Universidade Federal Sergipe, Hospital e Maternidade São João de Deus

Laranjeiras, Sergipe, 49060-025, Brazil

Location

Fundação Faculdade Regional De Medicina De São José Do Rio Preto

São Pedro, São Paulo, 15090-000, Brazil

Location

MeSH Terms

Conditions

Chikungunya Fever

Condition Hierarchy (Ancestors)

Alphavirus Infections; Arbovirus Infections; Vector Borne Diseases; Infections; Mosquito-Borne Diseases; Virus Diseases; Togaviridae Infections; RNA Virus Infections

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 19, 2025
• First Posted: November 28, 2025
• Study Start: February 2, 2026
• Primary Completion (Estimated): October 31, 2026
• Study Completion (Estimated): February 28, 2027
• Last Updated: February 11, 2026

Record last verified: 2026-02

Locations

BR (4)