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.