DTaP (Diphtheria, Tetanus, Pertussis) Vaccine: What you need to know · Why get vaccinated? · DTaP vaccine · Talk with your health care provider · Risks of a. Babies need 3 shots of DTaP to build up high levels of protection against diphtheria, tetanus, and whooping cough. DTaP is a vaccine that helps children younger than age 7 develop immunity to three deadly diseases caused by bacteria: diphtheria, tetanus, and whooping. Diphtheria, tetanus, and pertussis vaccine (DTaP) can help prevent these diseases. DTaP vaccine can help protect your child from diphtheria, tetanus, and pertussis.