The tetanus vaccine is a preventive shot that protects against tetanus, a serious bacterial infection caused by Clostridium tetani. This bacteria can enter the body through wounds or cuts, leading to muscle stiffness and spasms. The vaccine helps the immune system recognize and fight the bacteria if exposed in the future. Typically, the tetanus vaccine is given as part of a combination shot, often combined with vaccines for diphtheria and pertussis (whooping cough). It is recommended for children and adults, with booster shots needed every ten years to maintain immunity.