A tetanus shot is a vaccine that prevents a bacterial infection caused by Clostridium tetani. This bacteria is commonly found in soil, dirt, and feces and can enter the body through cuts, scratches, or puncture wounds. Once inside the body, the bacteria release toxins that cause muscle stiffness, spasms, and serious complications such as difficulty breathing. Tetanus can lead to paralysis and even death if not treated, which is why prevention through vaccination is key.

The ingredient in the tetanus vaccine is called tetanus toxoid. It works by stimulating your immune system to create antibodies that protect you if you’re exposed to the bacteria in the future.