Xu-Lin WANG ; Min-Qi CEHN ; Wen-Yu LI ; Jin-Jian FU ; Xiao-Hua YE
Chinese Journal of Contemporary Pediatrics 2021;23(4):363-368
Carrier State ; Child ; Child, Preschool ; China/epidemiology* ; Cluster Analysis ; Humans ; Infant ; Nasopharynx ; Pneumococcal Infections ; Streptococcus pneumoniae