Diphtheria is a serious bacterial infection. You can catch it from a person who has the infection and coughs or sneezes. It usually affects the nose and throat and causes a bad sore throat, swollen glands, fever and chills. But if it is not properly diagnosed and treated it produces a poison in the body that can cause serious complications such as heart failure or paralysis. The diphtheria, pertussis and tetanus (DPT) vaccine can prevent diphtheria, but its protection does not last forever. Adults should get another dose, or booster, every 10 years. Diphtheria is very rare in the United States because of the vaccine.