Clinical Characteristics, Complications, and Mortality Risk Factors in Severe Pediatric Pertussis: A Retrospective Single-Center Study in Southwest China

Background and Objective Pertussis remains a serious threat to infants and young children, especially when complicated by pneumonia or encephalitis. This study aimed to describe the clinical features, complications, treatments, and mortality risk factors in children with severe pertussis over ten years in Southwest China. Methods A retrospective study was conducted on hospitalized children with severe pertussis at the Children’s Hospital of Chongqing Medical University from 2015 to 2024. Clinical data were analyzed across groups with different complications. Mortality risk factors were identified using univariate and multivariate analyses. Results A total of 1,088 cases were included. Patients were grouped into severe pneumonia, encephalitis, and combined complications. Those with both pneumonia and encephalitis had more apnea, pulmonary hypertension, extreme leukocytosis, thrombocytosis, and A. baumannii infection. They required more intensive treatments ( P  < 0.05), had longer hospital stays, and the highest mortality. Seizures were more frequent in the encephalitis group, while elevated lactate and immunoglobulin use were less common ( P  < 0.05). Univariate analysis linked pulmonary hypertension, high lactate, lymphocytosis, and leukocytosis to mortality. Multivariate analysis identified pulmonary hypertension, exchange transfusion, and steroid use as independent death risk factors. Conclusion Severe pertussis in children is often complicated by pneumonia and/or encephalitis, making treatment more difficult. Rising antibiotic resistance and strain differences in Bordetella pertussis may reduce treatment effectiveness. The increase in severe cases after the pandemic may be due to lower population immunity. Promoting maternal pertussis vaccination in China is urgently needed as a preventive measure.