[Malignant pertussis: 3 case reports].

Three infants aged less than 2 months were hospitalized for malignant pertussis. Echocardiography showed pulmonary hypertension. High-frequency oscillations and nitric oxide were ineffective. Respiratory and hemodynamic conditions deteriorated secondarily. The third case received an exchange transfusion without success. All three infants died following multiorgan failure. Malignant pertussis is the leading cause of infectious death in infants less than 2 months of age, treatment is often ineffective, and prevention, targeting the population of young adults, is particularly important.