The Epidemiology of Pathogens in Community-Acquired Pneumonia Among Children in Southwest China Before, During and After COVID-19 Non-pharmaceutical Interventions: A Cross-Sectional Study

Abstract

Objective: This study aimed to investigate the pathogen epidemiology of community-acquired pneumonia (CAP) among children in Southwest China before, during and after the COVID-19 non-pharmaceutical interventions (NPIs). Methods: Pathogen data of hospitalised children with CAP, including multiple direct immunofluorescence test for seven viruses, bacterial culture and polymerase chain reaction (PCR) for Mycoplasma pneumoniae, were analysed across three phases: Phase I (pre-NPIs: 1 January 2019 to 31 December 2019), Phase II (NPI period: 1 January 2020 to 31 December 2020) and Phase III (post-NPIs: 1 January 2023 to 31 December 2023). Results: A total of 7533 cases were enrolled, including 2444, 1642 and 3447 individuals in Phases I, II and III, respectively. M. pneumoniae predominated in Phases I and III (23.4% and 35.5%, respectively). In Phase II, respiratory syncytial virus (RSV) emerged as the primary pathogen (20.3%), whereas detection rates of influenza A virus (Flu A) and M. pneumoniae were at a low level (1.8% and 9.6%, respectively). In Phase III, both Flu A (15.8%) and M. pneumoniae epidemic rebounded, whereas RSV detection rate returned to Phase I level, and detection rates of Streptococcus pneumoniae and Haemophilus influenzae decreased significantly compared to those in Phase I. Detection rates of adenovirus and parainfluenza virus type 3 decreased phase by phase. Age-stratified analysis and monthly variations supported the above findings. Seasonal patterns of multiple pathogens were disrupted during Phases II and III. Conclusions: COVID-19 NPIs exhibited a distinct impact on CAP pathogen epidemic among children, with post-NPIs increases observed in M. pneumoniae and Flu A prevalence. Continuous pathogen monitoring is crucial for effective prevention and control of paediatric CAP.