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

• Conditions: Chikungunya Virus Infection

• Registration Number: NCT07163845
• Lead Sponsor: Valneva Austria GmbH

Brief 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.

Study Timeline

• Status Verified: 2025-09
• Study First Submitted: 2025-09-01
• Study First Submitted QC: 2025-09-01
• Study First Posted: 2025-09-09
• Study Start: 2025-09-22
• Last Update Submitted: 2025-09-24
• Last Update Posted: 2025-09-25
• Primary Completion: 2025-12-15
• Study Completion: 2026-12-31

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 4988

Inclusion Criteria

1. Individuals residing in the selected municipalities of Brazil where the VLA1553 pilot vaccination strategy will be implemented.
2. Individuals ≥2 years of age
3. Individuals who sleep 3 nights a week or more in a household that is selected by cluster sampling.

Exclusion Criteria

1. Individuals or their legally accepted representatives (LAR) who are not willing or not able to provide informed consent (and assent, as required) according to country-specific procedures.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
To prospectively evaluate the association between vaccination uptake and previous CHIKV exposure (pre-existing immunity to CHIKV infection) after implementing a pilot vaccination in the age-group approved per label.	on Day 1

Trial Locations

Locations (4)

Universidade Federal Do Ceará; 🇧🇷 Fortaleza, Ceará, Brazil

Universidade Federal de Minas Gerais, CT Terapias Avançadas e Inovadoras; 🇧🇷 Belo Horizonte, Minas Gerais, Brazil

Centro de Pesquisas Clínicas Universidade Federal Sergipe, Hospital e Maternidade São João de Deus; 🇧🇷 Laranjeiras, Sergipe, Brazil

Fundação Faculdade Regional De Medicina De São José Do Rio Preto; 🇧🇷 São Pedro, São Paulo, Brazil