By InvitationNot Applicable

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

Brazil5,000 participantsStarted 2026-02-02

Plain-language summary

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

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. 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.

Exclusion criteria

. 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).

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

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

Timeframe: From enrollment until Day 60

Trial details

NCT IDNCT07254702

SponsorValneva Austria GmbH

Sponsor typeINDUSTRY

Study typeOBSERVATIONAL

Primary completion2026-10-31

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