Pertussis, also known as whooping cough, is very dangerous for newborns, infants and young children. Protect your baby and your family by making sure your TDaP vaccine is current. All pregnant women between 27 and 36 weeks of gestation need a TDaP vaccination. Additionally, anyone in the family who will come in contact with the new baby also should get a TDaP vaccination. Pertussis is a very contagious bacterial infection that causes uncontrollable, violent coughing that makes breathing difficult—or even impossible for tiny babies. Patients struggling to breathe make a “whooping” sound, which gives the disease its name.