The TDaP vaccine protects preteens and adults against three serious bacterial infections: tetanus, diphtheria, and pertussis (or whooping cough). Tetanus and diphtheria are rare in the United States today, but whooping cough continues to spread.

Tdap protects adults from whooping cough, which helps to protect infants who are too young to be vaccinated against whooping cough and could catch the disease from adults around them. Parents, siblings, and grandparents are often the source of whooping cough in infants.

A TDaP booster is usually given every 10 years with a single injection in the upper arm.

TDaP is different than the DTaP vaccine, which is given to infants and children in 5 doses starting at 2 months of age.