The DTaP vaccine is a combination vaccine that provides protection against diphtheria, tetanus, and whooping cough or pertussis. The vaccine is given as a series of five injections at ages 2 months, 4 months, 6 months, 15-18 months, and 4-6 years. The "a" in DTaP stands for "acellular," meaning that the whooping cough component contains only parts of the bacteria instead of the whole bacteria. The DTaP vaccine is only for children younger than 7 years old. A vaccine called Tdap is a booster shot that should be given at ages 11 to 12, and to older teens and adults who havent yet had a booster with pertussis coverage. Tdap contains a reduced dose of the diphtheria and pertussis vaccines and is approved for adolescents starting at age 7. Adults and teenagers should receive Tdap instead of the tetanus-diphtheria (Td) injection if it has been 10 years or more since their last tetanus-diphtheria vaccine.