High prevalence of Bordetella pertussis in young hospitalized infants with acute respiratory infection in the south of China: age- and season-dependent effects

Background and purpose: Pertussis remains a major public health concern in most countries, including China. Limited data is available about B. pertussis infection in China. We therefore studied the prevalence of infection by B. pertussis in a large pediatric hospital in the Shenzhen, southern China. Methods: Oropharyngeal/nasopharyngeal swabs were obtained from 17,104 inpatients aged between 10 days and 14 years with possible pertussis, enrolled from March 2014 to February 2018. A real time PCR assay targeting ptxA-Pr was used routinely to detect B. pertussis. Data were analyzed to describe the frequency and seasonality. Results: A total of 17,104 children were enrolled in the study of whom 772 (4.51%) were PCR positive for B. pertussis. More than two-thirds of the patients (72.30%) were less than 12 months of age and the detection rate decreased with age. The detection rates in spring and summer were significantly higher than in autumn and winter (X2=18.79, p <0.001). Conclusion: B. pertussis is highly prevalent in hospitalized children with acute respiratory tract infection in southern China, especially in non- or incompletely vaccinated newborns and infants (0 – 12 months of age). This strongly demands for expansion of the national pertussis vaccination program to protect infants. Funding: This study was supported by the Sanming Project of Medicine in Shenzhen (SZSM201512030) and by the Shenzhen Science and Technology Project (JCYJ20170303155012371). Declaration of Interest: The authors have declared that no competing interests exist. Ethical Approval: This study was approved by the Ethics Committee of Shenzhen Children’s Hospital.