whooping cough or pertussis, highly communicable infectious disease caused by the bacterium Bordetella pertussis. The early or catarrhal stage of whooping cough is manifested by the usual symptoms of an upper respiratory infection with bronchial involvement. After about two weeks the cough becomes paroxysmal; 10 to 15 coughs may follow in rapid succession before a breath is taken, which is the characteristic high-pitched crowing "whoop." An attack of coughing is accompanied by a copious discharge of mucus and, often, vomiting. Antibiotics and hyperimmune human serum are valuable in treatment. Rest and proper nutrition (especially if there is frequent vomiting) are important.
Whooping cough is a serious disease, especially in children under four years of age, since it may give rise to such complications as pneumonia, asphyxia, convulsions, and brain damage. For these reasons, it is recommended that all infants be actively immunized beginning at as early an age as possible (one to two months). The whole-cell pertussis vaccine available in the United States since the 1940s (see vaccination) became the subject of controversy when it was learned that a toxin contained in it might cause serious side effects and rarely death. A newer, acellular vaccine, which uses only the parts of the bacterium that stimulate immunity and is less likely to cause side effects, was approved for use in 1996. Five doses are administered over 4 to 6 years, with the first three doses given by 6 months of age. The acellular vaccine, however, is less persistent than its predecessor. It is now believed that adults whose childhood vaccinations are no longer completely effective and whose symptoms are less diagnostic may be the main carriers for the disease. Booster vaccinations are recommended for 11- and 12-year-olds and adults as a means of ameliorating this situation; persons with routine contact with infants should be vaccinated.