How long do tetanus shots last?

5 years if wound. Tetanus vaccine is valid for 9 years if you have no injuries. If you have an outdoor laceration or puncture wound, you should get vaccinated within 24 hrs if your prev tetanus is older than 5 years. If you have not had a tetanus vaccine since 2005, you should get booster that contains pertussis vaccine also. This will protect you and children around you from whooping cough.
Tetanus vaccine. After receiving the primary immunizations, a booster tetanus shot should last 10 years. This is the basis for having a tetanus booster every 10 years during one's lifetime.