Coughing, violently and rapidly, until all the Adult in pertussis has left the lungs and a person is forced to inhale. However, coughing fits can return with other respiratory infections for many months after the pertussis infection started. This helps provide some protection before the baby can be vaccinated. Sera from the control population were obtained during the same period as the specimens from patients. This is in agreement with the Adult in pertussis of Wright et al.