This is the paroxysmal phase. Gradually these symptoms abate in the convalescent phase. Infants have the highest hospitalization and complication rates. Fifty percent or more of infants who contract pertussis are hospitalised. Pertussis infection in the very small infant might also be implicated in some apparent SIDS cases.
Broken ribs are very common in full-blown adult pertussis.
Imagine coughing hard enough to break your ribs. Young children who get pertussis usually catch it from adults. The pertussis germ is widespread in the adult population, a fact unknown to parents and unfortunately, to many doctors who care for adults. Very similar percentages of adult incidence have been established around the developed world. Doctors who care for adults rarely even consider the diagnosis of pertussis in an adult unless the patient has a classic whoop at the end of the cough - a symptom which can often be absent.