4 yrs and 11 yrs
Tetanus boosters are given at kindergarten entry (4 or 5 years old) in the form of dtap
Then a different vaccine, tdap, which contains a tetanus booster is given again at age 11. A tetanus shot is good for 5-10 years. If there is an injury and the last tetanus shot was more than 5 years ago, then a booster may be needed right away.