Yellow Fever VaccineVAC-SIP-YFNCT06694766
VAC-SIP-YF (Vaccination- Safety & Immunogenicity During Pregnancy- Yellow Fever)
A study testing Blood sample collection in people with Yellow Fever Vaccine, run by Institut Pasteur at 1 site in France.
Trial summary
The aim of this study is to compare the immunogenicity induced by yellow fever vaccination administered during pregnancy with that induced by vaccination outside pregnancy, and to assess the maternal and fetal tolerance of this vaccination. 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
- Yellow Fever Vaccine
- What is being tested?
- Blood sample collection
- Type of treatment
- Vaccines, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 270 participants
- Where
- 1 siteFrance
- Study dates
- 24 Mar 2025to Mar 2030
- Phase
- Interventional
- 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
Who may be able to join
- Common :
- Person over 18 years of age at the time of the first yellow fever vaccination
- Female gender
- Oral consent obtained after subject has been informed
- Subject covered by Social Security with the exception of Aide Médicale d'Etat
- Specific to both groups :
- For women vaccinated during pregnancy (case): Primary yellow fever vaccination during pregnancy
- For women vaccinated outside pregnancy (control): Primary yellow fever vaccination outside pregnancy
Who cannot join
- Criteria common to both sections (tolerance and immunogenicity):
- Subject having received a second yellow fever vaccination
- Persons unable to give informed consent for participation
- Women born in areas where yellow fever is endemic
- Female adults under legal protection (guardianship or trusteeship)
- Specific criteria for participants in the immunogenicity section:
- Medical condition imcompatible with 18.5 mL blood
- Women who have not given written consent to participate in the study. immunogenicity
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Julia ABAD contact
France1 site, 1 recruiting
- Recruiting
Medical Center of Institut Pasteur
Paris, 75015
Kaoutar JIDAR, MD, kaoutar.jidar@pasteur.fr
Fabien TAIEB, MD, fabien.taieb@pasteur.fr
About this study
Official title: Comparative Study of Tolerance and Immunogenicity Induced by Primary Yellow Fever Vaccination in Pregnant and Non-pregnant Women
The aim of this study is to compare the immunogenicity induced by yellow fever vaccination administered during pregnancy with that induced by vaccination outside pregnancy, and to assess the maternal and fetal tolerance of this vaccination.
Read the detailed description
Yellow fever (YF), caused by the yellow fever virus (YFV), is an endemic disease in tropical and subtropical regions of South America and Africa. The virus is transmitted to humans by mosquitoes and can cause severe acute illness, leading to death in 20 to 60% of cases. There is currently no antiviral treatment available.
The yellow fever vaccine is a live attenuated virus vaccine recommended for individuals living in or traveling to tropical regions of Africa and South America. Under the International Health Regulations (IHR), cross-border travelers aged one year and older must present an immunization certificate issued by a government-approved international vaccination center. Globally, between twenty and sixty million doses are administered each year.
In France, the vaccine used against Yellow Fever is Stamaril® (Sanofi Pasteur MSD), which utilizes the 17D-204 strain. Due to insufficient data on the tolerance and immunogenicity induced by yellow fever vaccination during pregnancy, specific precautions and guidelines are recommended in this scenario. Currently, pregnancy is a relative contraindication for yellow fever vaccination. It may be considered for pregnant women who cannot postpone travel, are traveling to a yellow fever endemic area, and where the benefit-risk ratio of vaccination is deemed favorable by the attending physician.
This research consists of 2 sections:
- Tolerance section: related to yellow fever vaccination, will involve solely collecting retrospective data. This first component will be conducted during a telephone call led by the investigating physician.
- Immunogenicity section: to evaluate the immune response induced by yellow fever vaccination. This second component will be conducted during a visit to the CMIP, where a blood sample will be taken.
All women will participate in the tolerance assessment component. If they wish and sign the written consent, they may also participate in the immunogenicity assessment component. Following the telephone call, an appointment at the CMIP will be scheduled.
- Conditions
- Yellow Fever Vaccine
- Being tested
- Blood sample collection
- Keywords
- Yellow Fever Vaccination Tolerance Immunogenicity Pregnancy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Blood sample collectionProcedure or surgery
A blood sample collection of 18.5 mL will be required for the immunogenicity component.
| Study group | Role | What they receive |
|---|---|---|
| women vaccinated during pregnancy | Other | Participants who received a yellow fever vaccination during pregnancy Receives: Procedure: Blood sample collection |
| women vaccinated outside pregnancy | Other | Participants who received a yellow fever vaccination outside pregnancy Receives: Procedure: Blood sample collection |
What is being measured
The primary outcome is the main question the study is designed to answer.
Describe the immunogenicity induced by primary yellow fever vaccination during pregnancy and compare it to the immunogenicity induced by primary vaccination outside pregnancy
Proportion of participants with a neutralizing antibody rate above 1/10. A serological analysis will be performed to measure neutralizing antibody response by using PRNT 80 seroneutralization techniques.
Each woman vaccinated against YF during pregnancy will be matched with a woman vaccinated outside pregnancy based on age (+/- 5 years) and time since primary YF vaccination (+/- 6 months).
We anticipate that vaccination against YF during pregnancy will be equivalent in term of immunogenicity compared to vaccination against YF realized among non-pregnant women of the same age range. Based on the hypothesis of a protective immune response rate of 90% in the pregnant women group, a sample size in each group of 135, with a normal approximation test of proportions, will allow a type 1 risk of 0.05, a power of 80% and a minimum difference of 5%, in order to reject the null hypothesis according to which the protective immune response rates in the two groups are not equivalent.
Measured: 36 months
Secondary outcomes (3)
Describe the safety of yellow fever vaccination during pregnancy in women who have been vaccinated
The data collected for safety assessment regarding women will include:
- Occurrence of YEL-AND or YEL-AVD
- Local adverse effects (pain, oedema, erythema, satellite lymph node)
- Nausea, vomiting, diarrhea, fever, arthralgia, myalgia
- Other adverse events that occurred after vaccination
All adverse reactions will be collected following MedDRA guidelines. The proportion of averse events will be compared to that of the non pregnant women group and to that of histoical series.
Measured: 36 months
Describe the tolerability of yellow fever vaccination during pregnancy in the fetus and newborn.
Data collected for safety assessment regarding the fœtus and newborn will include :
- Proportion of miscarriage, stillbirth, premature birth, and low weight birth and compare it to that of general population
- From the infant health record:
- Apgar, weight, size, and cranial perimeter at birth
- Birth defect
- Physical examination at birth (day 8), 9 month and 24 months of life
Measured: 36 months
Create a biological collection for future studies on infectious/tropical diseases and the immune response to vaccination
This collection could allow :
- analysis of cellular response to yellow fever vaccine e.g., activation of dendritic cells, NK cells, B lymphocytes and various T lymphocytes
- exploration of participants' cellular immunity and identification of factors influencing the latter
- Create a cohort of vaccinated women to assess immunogenicity and safety of all vaccines received during pregnancy
Measured: 36 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Nov 2024
- Study start24 Mar 2025
- Primary completionMar 2028 (estimated)
- Study completionMar 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Yellow Fever VaccineStudies of the same condition, open and under way.
- More trials run by Institut PasteurThe sponsor's other registered studies.
- 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- * women vaccinated during pregnancy * women vaccinated outside pregnancy
- Masking
- None (open label)
- Enrolment
- 270 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Institut Pasteur
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Cerballiance
- Responsible party
- Sponsor
- Investigators
- Kaoutar JIDAR, MD, Principal investigator, Medical Center of l'Institut Pasteur (CMIP)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06694766
- Sponsor's protocol ID
- 2023-071
- Other IDs
- 2023-A02595-40
- Acronym
- VAC-SIP-YF
- Status last verified
- Nov 2025
- First submitted
- 14 Oct 2024
- Last updated
- 15 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparative Study of Tolerance and Immunogenicity Induced by Primary Yellow Fever Vaccination in Pregnant and Non-pregnant Women
- ClinicalTrials.gov ID
- NCT06694766
- Acronym / sponsor ID
- VAC-SIP-YF / 2023-071
- Conditions
- Yellow Fever Vaccine
- Keywords
- Yellow Fever Vaccination Tolerance Immunogenicity Pregnancy
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 270 participants (estimated)
- Lead sponsor
- Institut PasteurIndustry (pharma, biotech, devices)
- Collaborators
- Cerballiance
- Study start
- 24 Mar 2025 (actual)
- Primary completion
- Mar 2028 (estimated)
- Study completion
- Mar 2030 (estimated)
- First posted
- 19 Nov 2024 (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.
The aim of this study is to compare the immunogenicity induced by yellow fever vaccination administered during pregnancy with that induced by vaccination outside pregnancy, and to assess the maternal and fetal tolerance of this vaccination.
Detailed description
Yellow fever (YF), caused by the yellow fever virus (YFV), is an endemic disease in tropical and subtropical regions of South America and Africa. The virus is transmitted to humans by mosquitoes and can cause severe acute illness, leading to death in 20 to 60% of cases. There is currently no antiviral treatment available.
The yellow fever vaccine is a live attenuated virus vaccine recommended for individuals living in or traveling to tropical regions of Africa and South America. Under the International Health Regulations (IHR), cross-border travelers aged one year and older must present an immunization certificate issued by a government-approved international vaccination center. Globally, between twenty and sixty million doses are administered each year.
In France, the vaccine used against Yellow Fever is Stamaril® (Sanofi Pasteur MSD), which utilizes the 17D-204 strain. Due to insufficient data on the tolerance and immunogenicity induced by yellow fever vaccination during pregnancy, specific precautions and guidelines are recommended in this scenario. Currently, pregnancy is a relative contraindication for yellow fever vaccination. It may be considered for pregnant women who cannot postpone travel, are traveling to a yellow fever endemic area, and where the benefit-risk ratio of vaccination is deemed favorable by the attending physician.
This research consists of 2 sections:
- Tolerance section: related to yellow fever vaccination, will involve solely collecting retrospective data. This first component will be conducted during a telephone call led by the investigating physician.
- Immunogenicity section: to evaluate the immune response induced by yellow fever vaccination. This second component will be conducted during a visit to the CMIP, where a blood sample will be taken.
All women will participate in the tolerance assessment component. If they wish and sign the written consent, they may also participate in the immunogenicity assessment component. Following the telephone call, an appointment at the CMIP will be scheduled.
Study design
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- * women vaccinated during pregnancy * women vaccinated outside pregnancy
| Arm | Type | Receives |
|---|---|---|
| women vaccinated during pregnancy | Other | Procedure: Blood sample collectionParticipants who received a yellow fever vaccination during pregnancy |
| women vaccinated outside pregnancy | Other | Procedure: Blood sample collectionParticipants who received a yellow fever vaccination outside pregnancy |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Person over 18 years of age at the time of the first yellow fever vaccination
- Female gender
- Oral consent obtained after subject has been informed
- Subject covered by Social Security with the exception of Aide Médicale d'Etat
- For women vaccinated during pregnancy (case): Primary yellow fever vaccination during pregnancy
Key exclusion criteria (8 listed)
- Subject having received a second yellow fever vaccination
- Persons unable to give informed consent for participation
- Women born in areas where yellow fever is endemic
- Female adults under legal protection (guardianship or trusteeship)
- Medical condition imcompatible with 18.5 mL blood
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 |
|---|---|---|
| Blood sample collectionA blood sample collection of 18.5 mL will be required for the immunogenicity component. | Procedure or surgery | women vaccinated during pregnancy, women vaccinated outside pregnancy |
Primary outcome
Describe the immunogenicity induced by primary yellow fever vaccination during pregnancy and compare it to the immunogenicity induced by primary vaccination outside pregnancy
Time frame: 36 months
Proportion of participants with a neutralizing antibody rate above 1/10. A serological analysis will be performed to measure neutralizing antibody response by using PRNT 80 seroneutralization techniques. Each woman vaccinated against YF during pregnancy will be matched with a woman vaccinated outside pregnancy based on age (+/- 5 years) and time since primary YF vaccination (+/- 6 months). We anticipate that vaccination against YF during pregnancy will be equivalent in term of immunogenicity compared to vaccination against YF realized among non-pregnant women of the same age range. Based on the hypothesis of a protective immune response rate of 90% in the pregnant women group, a sample size in each group of 135, with a normal approximation test of proportions, will allow a type 1 risk of 0.05, a power of 80% and a minimum difference of 5%, in order to reject the null hypothesis according to which the protective immune response rates in the two groups are not equivalent.
3 secondary outcomes
Describe the safety of yellow fever vaccination during pregnancy in women who have been vaccinated
Time frame: 36 months
Describe the tolerability of yellow fever vaccination during pregnancy in the fetus and newborn.
Time frame: 36 months
Create a biological collection for future studies on infectious/tropical diseases and the immune response to vaccination
Time frame: 36 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 15 Dec 2025.
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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.
Julia ABAD contact
Kaoutar JIDAR, MD principal investigator
Medical Center of l'Institut Pasteur (CMIP)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Blood sample collection in people with Yellow Fever Vaccine, run by Institut Pasteur at 1 site in France.
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 8 inclusion and 8 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: looking for participants now, as of the sponsor's last update on 15 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. 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?
Contact Kaoutar JIDAR, MD (0140613817 ext. +33, kaoutar.jidar@pasteur.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Describe the immunogenicity induced by primary yellow fever vaccination during pregnancy and compare it to the immunogenicity induced by primary vaccination outside pregnancy (time frame: 36 months). 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 15 Dec 2025.