You usually need a Tdap shot once in adulthood, then a tetanus/diphtheria (Td or Tdap) booster every 10 years, with a few important exceptions.

Basic schedule

  • If you never had Tdap as a teen or adult: get one dose of Tdap now , then a Td or Tdap booster every 10 years for life.
  • If you already had a Tdap as a teen or adult: keep getting a Td or Tdap booster every 10 years.
  • Children: they do not get repeated Tdap; they get a 5‑dose DTaP series in childhood, then a single Tdap booster at 11–12 years.

Special situations

  • Pregnancy: one Tdap in every pregnancy , ideally at 27–36 weeks, even if your last Tdap was recent, to protect the newborn from pertussis.
  • Dirty or severe wound: if it has been 5 or more years since your last Td/Tdap, a booster is recommended for tetanus protection.
  • Catch‑up: teens and adults who missed earlier doses should still get one Tdap , then follow the 10‑year booster rule.

When to ask your doctor

  • If you are unsure when your last tetanus/TDap shot was.
  • If you have immune problems, are on chemotherapy/biologics, or have had a serious reaction to a vaccine in the past, since your schedule might need individual adjustment.

For a “quick scoop” answer: most adults need one Tdap dose, then a Td or Tdap booster every 10 years , with an extra Tdap in every pregnancy and sometimes after serious or dirty wounds.