What is the definition or description of: tdap vaccine?

Combination vaccine: It contains more tetanus toxoid, than diphtheria toxoid, and acellular pertussis. (hence big t and little d and p).These antigens are introduced by injection to make he body build antibodies against these bacteria.

Tetanus booster: Tetanus-diphtheria-pertussis vaccine.

Tet,Dip,Acellular Pe: It is a vaccine for diptheria, ttetanus;acellular pertussis it is given as a booster dose to children at 11 yeasr of age who already had primay immunization with dtap given in first and second year of life and also is given as a booster dose to adults and pregnant women these days as there is resurgence of prtussis(whooping cough).