Results
Among 94,889 children (51,105 males and 43,784 females), the overall MP positivity rate was 12.3%, with no significant difference between sexes. Across five clinical diagnostic groups, MP positivity rate was highest in the acute lower respiratory tract infections (ALRTIs) group (13.9%), followed by the SRLT group (12.8%); both were significantly higher than those in the chronic respiratory diseases (CRDs) group (8.8%), the acute upper respiratory tract infections (AURTIs) group (6.6%), and the non-respiratory diseases (NRDs) group (4.8%). MP positivity rates in the ALRTIs, AURTIs, NRDs, and SRLT groups showed significant seasonal variation, peaking in winter, followed by spring; both seasons exhibited significantly higher positivity rates than summer and autumn. Monthly MP positivity rate peaked in January and February across all groups, after which it generally decreased with mild fluctuations, with the ALRTIs group consistently exhibiting the highest positivity rate. Among children with ALRTIs and AURTIs, MP positivity rates were significantly higher in school-aged, preschool, and adolescent children than in toddlers, infants, and newborns (p < 0.001). Multivariable logistic regression analysis revealed that MP positivity was independently associated with healthcare setting (inpatient vs. outpatient/emergency, OR: 1.24, 95% CI: 1.15-1.35), and PCR assay type (multiplex vs. singleplex, OR: 2.45, 95% CI: 2.25-2.67).
