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

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT07163845

Enrollment

5354

Registered

2025-09-09

Start date

2025-09-22

Completion date

2026-12-31

Last updated

2026-02-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Chikungunya Virus Infection

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.

Interventions

BIOLOGICALLive-attenuated CHIKV vaccine VLA1553

Non-interventional study: VLA1553 is used in the pilot vaccination strategy which is carried out after this observational study.

Study design

Observational model

OTHER

Time perspective

CROSS_SECTIONAL

Eligibility

Sex/Gender

ALL

Age

2 Years to No maximum

Healthy volunteers

Yes

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.

Design outcomes

Primary

Measure	Time frame
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

Countries

Brazil

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 12, 2026