What is the difference between DTP, DTaP and Tdap?
DPT vaccine is a combination of three inactivated bacterial vaccines: diphtheria, pertussis and tetanus. There are many different forms and combinations of these vaccines licensed for use in the United States http://www.fda.gov/cber/vaccine/licvacc.htm. Some versions of the vaccine are only appropriate for adults and adolescents (Tdap, Td and TT). Various versions of the vaccine for infants and young children include DPT (whole cell pertussis), which is no longer used in the U.S.; DTaP (acellular pertussis) which was licensed in 1996 for babies; and DT (diphtheria, tetanus).