Identifying the irrationality of the diagnosis of “pertussis-like syndrome” to enhance diagnostic accuracy

The purpose of this study is to assess the rationale and epidemiological patterns of "pertussis-like syndrome" diagnoses. A comprehensive analysis of demographic, epidemiological, and etiological characteristics was conducted on 10,561 diagnosed "pertussis-like syndrome" cases across 33 Chinese hospitals. Post-coronavirus disease 2019 pandemic, the incidence of "pertussis-like syndrome" increased significantly. Infants under 1 year old accounted for 69.73% of these cases, and severe outcomes were particularly prevalent among younger infants. Among those admitted to the intensive care unit, 83.03% were under 6 months of age, and 75.00% of the four reported deaths occurring in infants were younger than 3 months. While infants under 1 year consistently represented over half of annual cases, their proportion declined from 82.93% in 2016 to 51.21% in 2022. In contrast, there has been a notable rise in cases among children older than 3 years. It is important to highlight that only 4.37% of cases were exclusively diagnosed as "pertussis-like syndrome," with the majority of patients presenting with comorbidities, particularly lower respiratory tract infections (93.61%). The common pathogens identified in the records included respiratory syncytial virus, <i>Mycoplasma pneumoniae</i>, <i>Haemophilus influenzae</i>, and parainfluenza virus. "Pertussis-like syndrome" exhibits a high degree of overlap with pertussis in terms of the age distribution of susceptible populations and epidemiological patterns. To improve diagnostic accuracy, we recommend strengthening laboratory testing in suspected "pertussis-like syndrome" cases to confirm or rule out pertussis. For cases with identified pathogens that are not <i>Bordetella pertussis</i>, a precise pathogen-specific diagnosis should be established rather than relying on the ambiguous label of "pertussis-like syndrome." IMPORTANCE This study highlights the critical importance of reevaluating the diagnosis of "pertussis-like syndrome" to improve diagnostic accuracy and patient outcomes. The global resurgence of pertussis has underscored the need for precise identification of respiratory infections, particularly in pediatric populations. Our analysis of 10,561 cases across 33 hospitals in China revealed significant overlaps between "pertussis-like syndrome" and pertussis in terms of age distribution and epidemiological patterns. Cases diagnosed as "pertussis-like syndrome" may include undetected cases of pertussis. Moreover, the broad, ambiguous label of "pertussis-like syndrome" often masks the true causative pathogens. This imprecise diagnosis hinders targeted treatment and public health surveillance. Given advancements in pathogen detection technologies, we advocate for abandoning the "pertussis-like syndrome" label in favor of precise, pathogen-specific diagnoses. This shift may enhance diagnostic clarity, optimize clinical management, and strengthen efforts to monitor and control respiratory infections globally.