Maternal Determinants of Infant Immunity to Pertussis (MADI-02)

January 12, 2026 updated by: Tessa Goetghebuer, Centre Hospitalier Universitaire Saint Pierre
The overall objective of the project is to identify the determinants of antibody-mediated immunity in infants born to mothers immunized during pregnancy. Using maternal pertussis immunization as a model, the project will identify key predictors and potential determinants of vaccine responses in pregnant women, of the transfer of maternal antibodies to the newborn and of vaccine responses in infants. A systems biology approach will be used to delineate pre-vaccination and post-vaccination cellular and molecular correlates of the immune response to pertussis immunization in peripheral blood and in breastmilk.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The overall objective of the project is to identify the determinants of antibody-mediated immunity to pertussis in infants born to mothers immunized during pregnancy. Three specific objectives will be targeted:

  1. Determine the impact of pregnancy on the quality of antibody response to pertussis immunization and identify immune predictors of vaccine responses in pregnant and non-pregnant women.
  2. Identify immune predictors of the transfer of maternal antibodies to the newborn and the presence of antibody in breastmilk following pertussis immunization during pregnancy.
  3. Determine the impact of maternal antibodies on the quality of antibody response to pertussis immunization in infants born to mothers immunized or not immunized during pregnancy and identify immune predictors of vaccine responses in the first months of life.

To reach these objectives, 40 non-pregnant and 80 pregnant women will be recruited into the study and vaccinated with a single dose of a pertussis containing vaccine (Triaxis). Blood samples will be collected from:

  • non-pregnant women: before vaccination, and day 1/7/28 and month 5 post-vaccination.
  • pregnant women: before vaccination, day 1/7/28 post-vaccination, at delivery, and week 6/12 post-delivery. At week 6/12 post-delivery, breast milk samples will be collected as well.

At delivery, a placenta fragment will be collected.

In addition, infants 2-3 months old born either from mothers who were not vaccinated against pertussis during pregnancy (n=40) or born from mothers who were vaccinated against pertussis during pregnancy (n=80) will be recruited in the study. Infants will be vaccinated with three doses of a pertussis containing vaccine (Vaxelis), each one month apart starting from 2-3 months of age. Blood samples will be collected from:

  • infants from vaccinated mothers: cord blood, before 1st vaccine dose, day 1 post 1st vaccine dose, before 3rd vaccine dose, and day 28 post 3rd vaccine dose.
  • infants from unvaccinated mothers: before 1st vaccine dose, day 1 post 1st vaccine dose, before 3rd vaccine dose, and day 28 post 3rd vaccine dose.

Study Type

Interventional

Enrollment (Actual)

200

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Belgium
      • Brussels, Belgium, 1000
        • CHU Saint-Pierre

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • For non-pregnant & pregnant women Age between 18 and 45 years Eligible for Tdap vaccination
  • For infants Born to mothers vaccinated or not with Tdap Vaccinated with hexavalent vaccine Age between 2 and 3 months

Exclusion Criteria:

  • For pregnant and non-pregnant women

    • Inability to understand the nature and extent of the study and the procedures required
    • Grade III/IV anemia,
    • Acute infection at the time of immunization
    • Chronic infections such as Hepatitis B Virus (HBV), Hepatitis C Virus (HCV) or Human Immunodeficiency Virus (HIV) infection, acute toxoplasmosis
    • Current or recent use of immunosuppressive drugs
    • Active neoplasia
    • Other vaccine(s) administered at the same time as Tdap vaccination (wash out of 4 weeks after others vaccinations and 28 days after Tdap vaccination )

  • For pregnant women

    • Risk of premature delivery or intrauterine growth retardation
    • Twin or triplet pregnancies
  • For non-pregnant women Last Tdap vaccination < 12 months before

For infants:

  • Infants born before 35 weeks of gestation
  • Birthweight below 2.5 kg,
  • Severe neonatal distress
  • Serious congenital abnormalities or congenital infection.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Pregnant women
Pregnant women will receive one dose of Pertussis-containing vaccine during pregnancy.
Biological: Triaxis® (Pertussis-containing vaccine)

Triaxis® (Pertussis-containing vaccine) will be administered:

  • in non-pregnant women presenting to the Travel and Vaccine clinic for pertussis immunization only or hospital member staff requiring Tetanus Toxoid (TT)-booster immunisation
  • in Pregnant women between 16 and 29 weeks of gestation.
Active Comparator: Non pregnant women
Non-Pregnant women will receive one dose of Pertussis-containing vaccine.
Biological: Triaxis® (Pertussis-containing vaccine)

Triaxis® (Pertussis-containing vaccine) will be administered:

  • in non-pregnant women presenting to the Travel and Vaccine clinic for pertussis immunization only or hospital member staff requiring Tetanus Toxoid (TT)-booster immunisation
  • in Pregnant women between 16 and 29 weeks of gestation.
Active Comparator: Infants born to Tdap-vaccinated mothers
Infants whose mothers have been immunized during pregnancy with Tdap vaccine. Infants will receive three doses of Pertussis-containing vaccine (with 28 days interval starting at two months of age).
Biological: Vaxelis® (Pertussis-containing vaccine)
Vaxelis® (Hexavalent vaccine) will be proposed in infants at 8, 12 and 16 weeks of life.
Active Comparator: Infants born to non Tdap-vaccinated mothers

Infants whose mothers have not been immunized during pregnancy with Tdap vaccine.

Infants will receive three doses of Pertussis-containing vaccine (with 28 days interval starting at two months of age).
Biological: Vaxelis® (Pertussis-containing vaccine)
Vaxelis® (Hexavalent vaccine) will be proposed in infants at 8, 12 and 16 weeks of life.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
IgG titers specific to Bordetella Pertussis Antigens by Enzyme-linked immunosorbent assay (ELISA)
Time Frame: Day 28 post-vaccination

IgG titers specific to Bordetella Pertussis Antigens will be assessed by ELISA:

  • in women (pregnant and non-pregnant) at 28 days post vaccination
  • in infants (from unvaccinated mothers and mothers vaccinated during pregnancy) at 28 days post third vaccine dose
Day 28 post-vaccination
IgG titers specific to Bordetella Pertussis Antigens by Enzyme-linked immunosorbent assay (ELISA)
Time Frame: At delivery

IgG titers specific to Bordetella Pertussis Antigens will be assessed by ELISA:

  • in women vaccinated during pregnancy, at delivery
  • in umbilical cord blood of infants born to mothers vaccinated during pregnancy
At delivery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
IgG titers specific to Bordetella Pertussis Antigens by Enzyme-linked immunosorbent assay (ELISA)
Time Frame: up to 9 month after vaccination

IgG titers specific to Bordetella Pertussis Antigens will be assessed by ELISA:

  • in pregnant women (PW): at day of vaccination , day 7 post-vaccination, week 6 and 12 post-delivery
  • in non-pregnant women (non PW): at day of vaccination, day 7 and Month 5 post-vaccination
  • in infants (from unvaccinated mothers and mothers vaccinated during pregnancy) at day of first and third vaccine dose
up to 9 month after vaccination
CD4+ T cell frequencies specific to Bordetella Pertussis Antigens by flow cytometry
Time Frame: up to 9 month after vaccination

The percentage of CD4+ T cells expressing any of the following biomarkers (CD154, Interferon gamma, IL-2) in response to in vitro stimulation with Bordetella Pertussis Antigens will be measured by flow cytometry:

i. in pregnant and non-pregnant women: at day of vaccination, and day 28 post vaccination

ii. in infants (from unvaccinated mothers and mothers vaccinated during pregnancy) at day of first vaccine dose and 28 days after third vaccine dose
up to 9 month after vaccination

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Centre Hospitalier Universitaire Saint Pierre

Collaborators

Université Libre de Bruxelles

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 12, 2023

Primary Completion (Actual)

December 23, 2025

Study Completion (Actual)

December 23, 2025

Study Registration Dates

First Submitted

October 5, 2022

First Submitted That Met QC Criteria

May 3, 2023

First Posted (Actual)

May 12, 2023

Study Record Updates

Last Update Posted (Actual)

January 13, 2026

Last Update Submitted That Met QC Criteria

January 12, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • B0762022220909

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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