Pertussis Vaccine in Healthy Pregnant Women

The purpose of this study is to look at the safety and immunogenicity of a combination vaccine that includes tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap). The study will be conducted in 48 pregnant women and 32 non-pregnant women. Safety of the newborn infant and the effect of the mother's vaccination on the infants' immune responses prior to vaccinating infants with another combination vaccine to protect against diphtheria, tetanus, and pertussis will be evaluated. Participants will be 18-45 years old. Pregnant volunteers will be 30-32 weeks pregnant and at a low risk for pregnancy complications. Pregnant volunteers will receive 2 injections (1 vaccine and 1 placebo, inactive substance); non-pregnant volunteers will receive 1 injection of vaccine. Blood samples will be collected from the mother and infant, along with the baby's growth measurements. Participation for mother infant pairs is about 15 months and about 7 months for non-pregnant women.