Pertussis, or whooping cough, is an acute infectious disease caused by the bacterium Bordetella pertussis. Outbreaks were first described in written records in the 16th century by Guillaume de Baillou in France. 

Pertussis has an incubation period of seven to ten days. Symptoms in the early stages include running nose, sneezing, low-grade fever, and a mild cough. Symptoms in the middle stage include bursts of numerous, rapid coughs, due to difficulty expelling thick mucus, accompanied by a high-pitched whooping sound. Vomiting and exhaustion can follow the coughing episodes. In the third or convalescent stage of pertussis, symptoms include gradual recovery, with fewer coughing episodes until they disappear. However, rapid coughing bursts often recur with subsequent respiratory infections for many months after the onset of pertussis. Pertussis can be deadly for infants, due to pertussis-related complications like bacterial pneumonia. Other complications for anyone with pertussis can include neurologic complications such as seizures and encephalopathy, and dehydration, anorexia, and middle ear infections.

Jules Bordet and Octave Gengou first isolated the organism in 1906. It was a very common childhood disease in the 20th century United States, with more than 200,000 cases reported annually. Pertussis had a high rate of mortality, especially for infants. The whole-cell pertussis vaccine became widely available in the United States in the 1940s, although it was first licensed in 1914. It was crudely made and had limited use until the 1940s, because of reports of serious side effects including death.