The Td vaccine protects adults against tetanus and diphtheria. Tetanus and diphtheria are very serious diseases, and people who become infected often have severe complications. Td is given as a booster dose every 10 years, but it can also be given earlier after a severe and dirty wound or burn.

Another vaccine called Tdap, protects against pertussis (whooping cough) in addition to tetanus and diphtheria. Every adult should get one dose of the Tdap vaccine as soon as possible if they did not receive it as an adolescent. (A dose of Tdap can replace one of the Td booster shots.) Tdap is especially important for pregnant women and anyone who is in close contact with a baby younger than 12 months of age.


Commonly known as lockjaw, tetanus is a severe disease that causes stiffness and spasms of the muscles. Unlike other vaccine-preventable diseases, which are transferred from person to person, tetanus bacteria are found in places such as dirt, dust, and manure, and can therefore never be eradicated. The bacteria enter the body through any break in the skin, such as a cut or a puncture wound. A person can also be infected after a burn or animal bite.

There’s no cure for tetanus. Treatment focuses on managing complications until the effects of the tetanus toxin resolve. Deaths from tetanus occur most in people who haven’t been immunized.

Learn more about tetanus.


Diphtheria is a serious bacterial disease that can be spread from an infected person by coughing and sneezing. Diphtheria can also be spread by contaminated objects or foods.

Once infected, toxins, which are caused by the bacteria, can spread through the bloodstream to other organs and cause significant damage including injury to the heart, kidneys and other organs. Nerve damage and paralysis can also result.

Learn more about diphtheria.