pertussis, also known as whooping cough, is a disease that affects about 300,000 people in the us every year, out of 30–50 million cases per year. there is a vaccine that can prevent it, so most cases of it are in places where people cannot afford, cannot get, or refuse to get the vaccine. however, this vaccine does not work forever. the disease lasts about 6 weeks, and symptoms include vomiting, violent coughing, and other flu-like symptoms. it is called whooping cough for the sound an infected person makes when they cough.