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Study on the Best Timing for Pertussis Vaccination in Pregnant Women Using Diphtheria, Tetanus, and Pertussis Vaccine

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on understanding the best time to give the pertussis vaccine to pregnant women. Pertussis, also known as whooping cough, is a contagious disease that can be serious for babies. The vaccine being studied is called Triaxis, which is a combination vaccine that protects against diphtheria, tetanus, and pertussis. The study aims to see how the timing of the vaccine during pregnancy affects the immune system of the mother and the baby.

The purpose of the study is to assess how the timing of the Tdap vaccine (which stands for tetanus, diphtheria, and acellular pertussis) during pregnancy influences the immune responses in pregnant women. This includes looking at the levels of antibodies, which are proteins in the blood that help fight infections, in the mother's blood at different times: before the vaccine, after the vaccine, at the time of delivery, and six months after giving birth. The study will also measure the levels of antibodies in the baby's blood at birth to understand how well these protective proteins are passed from the mother to the baby through the placenta.

Participants in the study will receive the Tdap vaccine during their pregnancy. The study will involve several visits to monitor the immune responses, including blood tests to measure antibody levels and other immune markers. The study will also look at the presence of antibodies in breast milk six months after giving birth to see how the vaccine timing affects the baby's protection after birth. This research will help determine the best time to vaccinate pregnant women to provide the most protection for both the mother and the baby.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, the ability to provide informed consent is required. This means understanding the study details and agreeing to participate.

    Participants must be willing to receive a Tdap vaccine during pregnancy. This vaccine helps protect against diphtheria, tetanus, and pertussis (whooping cough).

  2. Step 2

    Vaccination

    The Tdap vaccine is administered as an injection. The timing of this vaccination during pregnancy is a key part of the study.

    Influenza and COVID-19 vaccinations during pregnancy are allowed, following Belgian recommendations.

  3. Step 3

    Follow-up visits

    Participants are expected to attend follow-up visits and be accessible by phone until 6 months after giving birth.

    These visits are important for monitoring health and collecting necessary data for the study.

  4. Step 4

    Blood sample collection

    Blood samples will be collected at different times: before the Tdap vaccination, after the vaccination, at delivery, and 6 months postpartum.

    These samples help measure antibody levels and other immune responses.

  5. Step 5

    Cord blood collection

    At delivery, a sample of cord blood will be collected. This helps measure the transfer of antibodies from the mother to the baby.

  6. Step 6

    Breastmilk sample collection

    Six months after giving birth, a breastmilk sample will be collected. This helps measure antibody levels and other characteristics in the milk.

Who can join the trial?

6 criteria

  • Must be pregnant.
  • Must be able to provide informed consent (this means you understand the study and agree to participate).
  • Must be willing to receive a Tdap vaccine (a vaccine that protects against tetanus, diphtheria, and pertussis) during pregnancy.
  • Must plan to be available for follow-up visits and phone calls until 6 months after giving birth.
  • Receiving influenza (flu) and COVID-19 vaccines during pregnancy is allowed, following Belgian health recommendations.
  • Must be female.

Who cannot join the trial?

4 criteria

  • Not being pregnant.
  • Not being within the specified age range for the study.
  • Not being female.
  • Being part of a vulnerable population that the study does not include.
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Investigated drugs

Pertussis Vaccine The pertussis vaccine is designed to protect against whooping cough, a highly contagious respiratory disease. In this clinical trial, the focus is on understanding how the timing of the vaccine during pregnancy affects the immune system of pregnant women. The goal is to see how well the vaccine helps the body create defenses against the disease, both during pregnancy and after giving birth. This information can help determine the best time for pregnant women to receive the vaccine to ensure maximum protection for both the mother and the baby.

What is already known about the treatment

Pertussis Vaccine – The pertussis vaccine is administered as an injection, typically given in the arm. It is currently used in medical practice to protect against whooping cough, especially in pregnant women to safeguard both the mother and the newborn. The main therapeutic indication is to prevent pertussis infection, which can be severe in infants. At the molecular level, the vaccine works by stimulating the body's immune system to produce antibodies against the pertussis bacteria, providing immunity. It is classified as a vaccine, which is a type of biological preparation that provides active acquired immunity to a particular infectious disease.

Investigated diseases

Pertussis – Pertussis, also known as whooping cough, is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis. It begins with symptoms similar to a common cold, such as a runny nose, mild cough, and fever. As the disease progresses, severe coughing fits develop, which can produce a high-pitched "whoop" sound when the person breathes in. These coughing fits can last for weeks and may lead to vomiting or exhaustion. The disease is particularly serious in infants and young children. Pertussis spreads through respiratory droplets when an infected person coughs or sneezes.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-518692-56-00Estimated enrolment96 patientsSponsorUniversity Of Antwerp

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