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

## TL;DR

This study shows that the diagnosis of 'pertussis-like syndrome' is often inaccurate and overlaps with actual pertussis, especially in infants, and suggests more precise pathogen testing to improve diagnosis and public health efforts.

## Contribution

The study reveals the diagnostic ambiguity of 'pertussis-like syndrome' and advocates for replacing it with pathogen-specific diagnoses using modern detection methods.

## Key findings

- Infants under 1 year old made up 69.73% of 'pertussis-like syndrome' cases, with severe outcomes concentrated in younger infants.
- Only 4.37% of cases were exclusively diagnosed as 'pertussis-like syndrome,' with most having comorbidities like lower respiratory tract infections.
- Common pathogens included respiratory syncytial virus, Mycoplasma pneumoniae, and parainfluenza virus, indicating the syndrome's overlap with other infections.

## Abstract

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, Mycoplasma
pneumoniae, Haemophilus influenzae, 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
Bordetella pertussis, a precise pathogen-specific
diagnosis should be established rather than relying on the ambiguous label
of “pertussis-like syndrome.”

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.