Whooping cough, also known as pertussis, is a bacterial infection that is spread through the air when an infected person coughs or sneezes. Symptoms typically start out like a common cold, with a runny nose, sneezing, and a mild cough. However, after a week or two, the cough can become more severe, with a “whooping” sound when the person tries to catch their breath. Whooping cough can be particularly dangerous for infants and young children, as well as for pregnant women and people with weakened immune systems. Vaccination is the most effective way to prevent whooping cough.