Sample collection
This study was proceeded from January, 2020 to December, 2020 in Henan province of China. Samples were collected from Henan Children’s Hospital, Zhengzhou, China. A total of 1237 samples were collected from patients 14 years old or younger preliminarily confirmed with CAP on the clinician’s decision. The exclusion criteria were as follows: (a) few cells in the specimen or insufficient amount of nucleic acid, (b) respiratory tract infection with a precise etiological diagnosis. This study was approved by the Ethics Committee of the Zhengzhou Children’s Hospital (Approval number:2021-K-073). Informed consent was taken from parents or guardians.