During the study, participants will receive one of these vaccines as a booster shot. Later, they will be exposed to a carefully controlled amount of pertussis bacteria through the nose. The researchers will then collect samples from the nose over several weeks to check for the presence of bacteria. Participants will receive azithromycin, an antibiotic, as part of the study protocol to ensure safety.

This is a Phase 4 study, which means the vaccines being tested are already approved for use but are being studied to gather additional information about their effects. The study will help understand how vaccination might prevent the bacteria from establishing itself in the nose, which could reduce the spread of whooping cough in communities.

The purpose of the study is to identify factors that influence how well infants develop immunity to whooping cough when their mothers are vaccinated during pregnancy. The study will look at how antibodies, which are proteins in the blood that fight infections, are transferred from the mother to the baby and how the baby’s immune system responds to the vaccines. Pregnant women will receive the Tdap vaccine, which is a booster shot for tetanus, diphtheria, and pertussis, to help protect their newborns from whooping cough.

Participants in the study will include pregnant women and their infants. The study will follow the infants from birth to see how their immune systems respond to the vaccines. The research aims to provide valuable insights into how maternal vaccination can protect infants from whooping cough and improve vaccine strategies for better infant health outcomes.