“…In infants with severe pertussis and severe leukocytosis, early reduction of white blood cell therapy may be a helpful and rapid life-saving treatment before cardiopulmonary complications develop. Among other studies (except for case reports) ( Table 4 ) [ 57–80 ], the major study designs were descriptive studies (62.5%, 15/24), case-control studies (20.8%, 5/24), and cohort studies (12.5%, 3/24); 45.8% (11/24) analyzed the risk factors associated with severe infection or death; Other contents involved epidemiology (12.5%, 3/24), clinical manifestations (8.3%, 2/24), pathological features (12.5%, 3/24), treatment (16.7%, 4/24), and disease burden (4.2%, 1/24). Increased white blood cell (81.8%, 9/11) is one of the risk factors associated with severe infection or death in infants with pertussis shown in most studies, as well as increased lymphocyte, apnea, co-infections, pulmonary hypertension, age, fever, cyanosis, and abnormal liver function.…”