Chikungunya Virus InfectionNCT07414524
VLA1553-403 Pregnancy Surveillance Study
An observational study of Chikungunya Virus Infection, run by Valneva Austria GmbH at 3 sites in Brazil.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older, women onlyHealthy volunteers can take part
- Conditions the study is for
- Chikungunya Virus Infection
- What is being tested?
- Live-attenuated CHIKV vaccine VLA1553 and Vaccine(s) approved for use during pregnancy by the MoH
- Type of treatment
- Vaccines
- How many people
- 200 participants
- Where
- 3 sitesBrazil
- Study dates
- 11 Jun 2026to 31 Dec 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- Healthy volunteers accepted
- Adult, Older adult
Study population: The control group will consist of women who have received vaccine(s) approved for use during pregnancy by the MoH and who meet the matching criteria.
Who may be able to join
- 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.
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- 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.
Who cannot join
- 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.
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Brazil3 sites
Universidade Federal de Minas Gerais, CT Terapias Avançadas e Inovadoras
Belo Horizonte, Minas Gerais, 31270-901
Centro de Pesquisas Clínicas Universidade Federal Sergipe, Hospital e Maternidade São João de Deus
Laranjeiras, Sergipe, 49060-025
Fundação Faculdade Regional De Medicina De São José Do Rio Preto
São Pedro, São Paulo, 15090-000
About this study
Official title: Observational Study to Evaluate the Safety of Live-attenuated Chikungunya Virus Vaccine (VLA1553) in Pregnant Women Exposed to the Vaccine in Brazil
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.
Read the 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.
- Conditions
- Chikungunya Virus Infection
- Being tested
- Live-attenuated CHIKV vaccine VLA1553, Vaccine(s) approved for use during pregnancy by the MoH
- Medical subject headings
- Chikungunya Fever
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Live-attenuated CHIKV vaccine VLA1553Biological
Non-interventional study: VLA1553 is used in the pilot vaccination strategy which will start along with this observational study.
Vaccine(s) approved for use during pregnancy by the MoHBiological
Vaccine(s) approved for use during pregnancy by the MoH
| Study group | Role | What they receive |
|---|---|---|
| VLA1553 group | Women vaccinated with the chikungunya virus vaccine (VLA1553) anytime during their pregnancy or within 30 days preceding their last menstrual period. Receives: Biological: Live-attenuated CHIKV vaccine VLA1553 | |
| Control group | Women who have received vaccine(s) approved for use during pregnancy by the MoH and who meet the matching criteria. Receives: Biological: Vaccine(s) approved for use during pregnancy by the MoH |
What is being measured
The primary outcome is the main question the study is designed to answer.
Frequency (n,%) of individuals with any outcome (pregnancy and infant health), as described in the protocol.
Pregnancy and infant outcomes will be collected as follows:
- Pregnancy outcomes: stillbirths, pregnancy terminations (spontaneous and elective), preterm deliveries, neonatal deaths and term live births.
- Infant outcomes: births small for gestational age, major congenital malformations.
Measured: Study start through study completion, an average of 12 months
Frequency (n,%) of specific outcomes (pregnancy and infant health), as described in the protocol.
Pregnancy and infant outcomes will be collected as follows:
- Pregnancy outcomes: stillbirths, pregnancy terminations (spontaneous and elective), preterm deliveries, neonatal deaths and term live births.
- Infant outcomes: births small for gestational age, major congenital malformations.
Measured: Study start through study completion, an average of 12 months
Secondary outcomes (4)
Frequency (n,%) of individuals with any outcome (pregnancy and infant health), as described in the protocol in the VLA1553 group and the control group.
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.
Measured: 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.
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.
Measured: 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.
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.
Measured: 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.
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.
Measured: Study start through study completion, an average of 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Feb 2026
- Study start11 Jun 2026
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chikungunya Virus InfectionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Valneva Austria GmbH
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Butantan Foundation, Coalition for Epidemic Preparedness Innovations
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07414524
- Sponsor's protocol ID
- VLA1553-403
- Status last verified
- Jul 2026
- First submitted
- 9 Feb 2026
- Last updated
- 20 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 20 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Observational Study to Evaluate the Safety of Live-attenuated Chikungunya Virus Vaccine (VLA1553) in Pregnant Women Exposed to the Vaccine in Brazil
- ClinicalTrials.gov ID
- NCT07414524
- Acronym / sponsor ID
- VLA1553-403
- Conditions
- Chikungunya Virus Infection
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Valneva Austria GmbHIndustry (pharma, biotech, devices)
- Collaborators
- Butantan Foundation, Coalition for Epidemic Preparedness Innovations
- Study start
- 11 Jun 2026 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 17 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| VLA1553 group | – | Biological: Live-attenuated CHIKV vaccine VLA1553Women vaccinated with the chikungunya virus vaccine (VLA1553) anytime during their pregnancy or within 30 days preceding their last menstrual period. |
| Control group | – | Biological: Vaccine(s) approved for use during pregnancy by the MoHWomen who have received vaccine(s) approved for use during pregnancy by the MoH and who meet the matching criteria. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The control group will consist of women who have received vaccine(s) approved for use during pregnancy by the MoH and who meet the matching criteria.
Key inclusion criteria (9 listed)
- 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.
- 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.
Key exclusion criteria (2 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Live-attenuated CHIKV vaccine VLA1553Non-interventional study: VLA1553 is used in the pilot vaccination strategy which will start along with this observational study. | Biological | VLA1553 group |
| Vaccine(s) approved for use during pregnancy by the MoHVaccine(s) approved for use during pregnancy by the MoH | Biological | Control group |
Primary outcome
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.
4 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Study start through study completion, an average of 12 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Jul 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Chikungunya Virus Infection, run by Valneva Austria GmbH at 3 sites in Brazil.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 20 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Brazil. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Jul 2026.