Hi,
D=Diphtheria (a type of throat infection)
P=Pertussis (whooping cough)
(aP=acellular pertussis)
T=Tetanus (lockjaw)

Thanks for the first question! All 3 vaccines contain protect against all 3 (tetanus, diphtheria, and pertussis). The only difference is the amount of each component in the particular vaccine. Whether you or your child gets DTaP or Tdap depends mainly on the age.

Pertussis is whooping cough, which has made a resurgence lately. We used to use DTP, which was whole cell pertussis. DTP caused a lot of high fevers, which the more purified DTaP does not. DTP is not used any more because of the more favorable side effect profile of DTaP. Did you know that pregnant women are now recommended to receive the Tdap vaccine with EACH pregnancy? This is a new recommendation. Also, caregivers of infants, such as parents and grandparents should receive the Tdap vaccine.

Quote Originally Posted by mslarrison View Post
What is the difference between DTP, DTaP and Tdap?