DTaP stands for Diphtheria, Tetanus, and Pertussis. It is a vaccine that is given to infants and young children to protect them against these three diseases. Diphtheria is a bacterial infection that can cause severe throat and breathing problems. Tetanus, also known as lockjaw, is caused by a bacterial toxin and can lead to muscle stiffness and spasms. Pertussis, or whooping cough, is a highly contagious respiratory infection that can cause severe coughing fits. The DTaP vaccine is typically given in a series of doses starting at 2 months of age, with additional doses given at 4 and 6 months, and booster shots given at 4-6 years and 11-12 years.