NCT07163845

Assessment of Chikungunya Virus Seroprevalence Before VLA1553 Vaccination in the Municipalities Selected for Participation in the VLA1553 Pilot Vaccination Strategy in Brazil

• Status: Active Not Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 5,354 (actual)
• Sponsor: Valneva Austria GmbH · Industry
• Sex: All
• Age: 2 Years
• Healthy volunteers: Accepted

Summary

This is a cross-sectional serosurvey using household cluster sampling conducted before the VLA1553 pilot vaccination strategy will be implemented in about 10 municipalities in Brazil.

Detailed description

Households will be selected randomly using a multi-stage random sampling at the census tract, street, and household levels, to select study participants. The study aims to prospectively evaluate the association between vaccination uptake and previous CHIKV exposure (pre-existing immunity to CHIKV infection) in the age-group approved per label in Brazil (e.g., adults \[≥18 years of age\] or individuals ≥12 years of age). Seroprevalence among vaccinated and unvaccinated individuals will be used to parameterize a probabilistic bias analysis conducted as part of the VE study. Finally, the study will explore the prevalence of CHIKV exposure in the different study communities before the VLA1553 pilot vaccination strategy in individuals ≥2 years of age.

Conditions

• Chikungunya Virus Infection

Interventions

Type	Name	Description
BIOLOGICAL	Live-attenuated CHIKV vaccine VLA1553	Non-interventional study: VLA1553 is used in the pilot vaccination strategy which is carried out after this observational study.

Timeline

• Start date: 2025-09-22
• Primary completion: 2026-07-31
• Completion: 2026-12-31
• First posted: 2025-09-09
• Last updated: 2026-02-11

Locations

4 sites across 1 country: Brazil