What is tetanus?
Tetanus (a.k.a. lockjaw) is an infection that affects the nerves that control your muscles.
What is diphtheria?
Diphtheria is caused by a bacterium that destroys healthy tissue in the respiratory system.
What is polio?
Polio is a disease of the spinal cord that can cause nerve damage and paralyze the muscles used for breathing, talking, eating and walking.