The Tdap vaccine is given to children when they reach the age of 11, as stated by WebMD. Children ages 7 and younger are given the DTap vaccine. Both the DTaP and Tdap vaccines help children to develop immunity to tetanus, diphtheria and whooping cough, or pertussis.
When children reach the age of 11, Tdap is administered as a booster which continues to protect them through adolescence and into adulthood. Tdap and DTaP both contain the bacteria that causes tetanus, whooping cough and diphtheria, in an inactivated form. Instead of producing a disease,this inactivated formcauses the body to produce antibodies that provide immunity.