Tdap is a combination vaccine that protects patients against three bacterial diseases: tetanus, diphtheria, and pertussis (whooping cough).
Tetanus is a rarity in the US these day, but if contracted it can cause painful muscle tightening and stiffness, usually all over the body. About 10% of patients infected with Tetanus will fall victim even after receiving the best medical care.
Diptheria is another rare disease here in the US, and often causes a thick coating to form in the back of the throat which can lead to breathing problems, heart failure, paralysis, and even death.
Pertussis is also known as Whooping Cough and causes bouts of severe coughing often causing difficulty breathing, vomiting, and in some cases, hospitalization.