You need a Tdap shot once as an adult if you have never received it before, and then a booster every 10 years to maintain protection against tetanus, diphtheria, and pertussis (whooping cough)

. Additional key points include:

• Adults who have never had Tdap should get a single dose, followed by Td or Tdap boosters every 10 years

• Pregnant women should receive a Tdap vaccine during each pregnancy, preferably between weeks 27 and 36, to protect the newborn

• If you have a deep or dirty wound and it has been more than 5 years since your last tetanus-containing vaccine, you may need a booster sooner

• There is some evidence that immunity to pertussis may wane faster (around 4-5 years), but official recommendations still advise boosters every 10 years for adults

In summary, the standard schedule is a single Tdap dose as an adult (if not previously received) and then a booster every 10 years with either Tdap or Td. Pregnant women get Tdap during every pregnancy regardless of prior vaccination