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Clinical Trials/NCT07414524
NCT07414524Enrolling By InvitationNot Applicable

Observational Study to Evaluate the Safety of Live-attenuated Chikungunya Virus Vaccine (VLA1553) in Pregnant Women Exposed to the Vaccine in Brazil

Valneva Austria GmbH3 sites in 1 country200 target enrollmentStarted: June 11, 2026Last updated:
Interventions

Trial Snapshot

Phase
Not Applicable
Status
Enrolling By Invitation
Enrollment
200
Locations
3
Primary Endpoint
Frequency (n,%) of individuals with any outcome (pregnancy and infant health), as described in the protocol.

Study Overview

Brief Summary

This post-marketing, observational study evaluates pregnancy and infant outcomes up to 12 weeks after delivery among women who received the chikungunya vaccine (VLA1553) during pregnancy or within 30 days before their last menstrual period. A matched comparator cohort of pregnant women vaccinated with routine, pregnancy-recommended vaccines (not exposed to VLA1553) is included. No study procedures beyond routine care are performed.

Detailed Description

This is an observational, non-interventional study in pregnant women who were vaccinated with the live-attenuated chikungunya virus vaccine (VLA1553) anytime during their pregnancy or within 30 days preceding their last menstrual period (VLA1553 group). The study protocol includes a comparator group of routinely vaccinated pregnant women not exposed to VLA1553 (control group).

The VLA1553 and control groups will be matched by gestational trimester and maternal age range (women <35 years of age at the time of enrolment and women >35 years of age) at exposure time. The study will collect information including vaccine exposure, demographic information, pregnancy data (e.g., date of positive pregnancy test, expected delivery date, previous pregnancy information), and medical history. Furthermore, data on pregnancy and infant outcomes up to 12 weeks post expected delivery date (EDD) will be compiled. The EDD will be calculated by counting 40 weeks from the first day of the LMP. This approach involves collecting data from the participating women onto the database by site staff and, if possible, confirmed and expanded by their PS-HCP as needed. Additionally, with consent, medical records may be accessed by study staff to further verify and supplement the information. This study will not provide or make recommendations on any vaccine use. Participation in the study is voluntary. Participation or lack of participation in this study will not change or influence a participant's standard of care.

Study Design

Study Type
Observational
Observational Model
Cohort
Time Perspective
Prospective

Eligibility Criteria

Ages
18 Years to — (Adult, Older Adult)
Sex
Female
Accepts Healthy Volunteers
Yes

Inclusion Criteria

  • VLA1553 vaccinated population:
  • Women who have received the single dose of the VLA1553 vaccine during pregnancy or within the 30 days prior to the first day of the last menstrual period.
  • Pregnant at the time of enrolment in the study.
  • The participant understands and agrees to comply with the study procedures.
  • Control group:
  • Pregnant at the time of enrolment in the study.
  • Women who have received vaccine(s) approved for use during pregnancy by the MoH and who meet the matching criteria described in the protocol.
  • The participant understands and agrees to comply with the study procedures.
  • Women who have not received the VLA1553 vaccine during pregnancy or within the 30 days prior to the first day of the last menstrual period.

Exclusion Criteria

  • Women who do not provide informed consent.
  • Women who are not part of the target population of the pilot vaccination strategy at the time of vaccination.

Arms & Interventions

VLA1553 group

Women vaccinated with the chikungunya virus vaccine (VLA1553) anytime during their pregnancy or within 30 days preceding their last menstrual period.

Intervention: Live-attenuated CHIKV vaccine VLA1553 (Biological)

Control group

Women who have received vaccine(s) approved for use during pregnancy by the MoH and who meet the matching criteria.

Intervention: Vaccine(s) approved for use during pregnancy by the MoH (Biological)

Outcomes

Primary Outcomes

Frequency (n,%) of individuals with any outcome (pregnancy and infant health), as described in the protocol.

Time Frame: Study start through study completion, an average of 12 months

Pregnancy and infant outcomes will be collected as follows: 1. Pregnancy outcomes: stillbirths, pregnancy terminations (spontaneous and elective), preterm deliveries, neonatal deaths and term live births. 2. Infant outcomes: births small for gestational age, major congenital malformations.

Frequency (n,%) of specific outcomes (pregnancy and infant health), as described in the protocol.

Time Frame: Study start through study completion, an average of 12 months

Pregnancy and infant outcomes will be collected as follows: 1. Pregnancy outcomes: stillbirths, pregnancy terminations (spontaneous and elective), preterm deliveries, neonatal deaths and term live births. 2. Infant outcomes: births small for gestational age, major congenital malformations.

Secondary Outcomes

  • Frequency (n,%) of individuals with any outcome (pregnancy and infant health), as described in the protocol in the VLA1553 group and the control group.(Study start through study completion, an average of 12 months)
  • Frequency (n,%) of specific outcomes (pregnancy and infant health), as described in the protocol in the VLA1553 group and the control group.(Study start through study completion, an average of 12 months)
  • Relative risk (RR) of any outcome (pregnancy and infant health) between pregnant women vaccinated with VLA1553 and pregnant women vaccinated with other vaccines recommended during pregnancy, as described in the protocol.(Study start through study completion, an average of 12 months)
  • Frequency (n,%) of individuals with SAEs (women and infants), following vaccination with VLA1553 or a control vaccine.(Study start through study completion, an average of 12 months)

Investigators

Sponsor Class
Industry
Responsible Party
Sponsor

Study Sites (3)

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