The most frequent symptoms of pertussis were persit cough over 2 weeks (42.1%), long duration paroxysmal cough (100%), paroxysmal cough with red face (100%) or with cyanosis (65.8%), whopping after cough (27.7%), start coughing at nigh (90.8%), vomiting (73.6%), rhinorrhea (80.3%), apnea (6.6%), the apnea occured mainly in children < 3 months old.