Viral etiology of acute respiratory tract infection among children under 5 years of age in Kunming City, China: a matched case–case–control study.

This article focuses on a matched case–case–control study conducted at Kunming Children's Hospital in China to investigate the association of respiratory viruses with acute upper respiratory tract infection (AURTI) and acute lower respiratory tract infection (ALRTI) in children aged five years and under. Using multiplex RT-PCR on oropharyngeal swabs from 278 ALRTI cases, 278 AURTI cases, and 278 healthy controls, the study found that human respiratory syncytial virus (RSV) and parainfluenza virus-3 (PIV-3) were independently associated with both ALRTI and AURTI, while adenovirus (ADV) was frequently detected in healthy controls and coinfections. Coinfections, particularly RSV/ADV, were more common in ALRTI cases. The findings suggest the potential utility of microbiota-based diagnostics using oropharyngeal samples for differentiating severe acute respiratory infections in pediatric patients.