adults should get a booster shot for tetanus and diphtheria every 10 years. and since immunity to pertussis also wears off you need a pertussis booster one time. so yes even though you've had the vaccinations before since the last one was over 10 years ago you do need a tdap to get immunized against tetanus diphtheria and pertussis. then every 10 years after that you'll just need the tetanus and diphtheria.
as an adult i received the dtp vaccine in 1996. would i still need the tdap? . i didn't have my immunization records when i went back to college in 1996 at age 22 so i received the dtp and mmr again at that time. would i still need to get the tdap booster or am i still protected by the dtp?