Abstract: acute lower respiratory tract infections (ALRTIs). Methods 202 NPA samples were detected by multiplex PCR for ADV, PIV1, 2, 3, Flu A, B, RhinoV A/B, RSV A, B, HMPV, Cov OC43/HKU1, Cov 229E/NL63. Human Bocavirus (HBoV) and WU polyomovirus (WUVyP) were detected by PCR. Results Among 202 NPA samples, 151 (74.8%) were pathogenic respiratory viruses positive. Of 151 virus positive patients, 54(26.7%) were 2 viruses co-infection. The most frequently detected virus was RSV(42.0%), followed by PIV and RhinoV A/B. There was a significant prevalent peak of RSV from December to March in next year. And PIV3 was the predominant pathogen from March to May. 2 serotypes of Cov co-existed in Tianjin. The most commonly co-infected virus was HBoV(61.5%). No significant age distribution of respiratory viruses was found. The prevalence of WUPyV in ALRTIs children was 19.8%. Conclusion RSV was the predominant pathogen in children with ALRTIs, We should focus on the high prevalence of WUPyV in ALRTIs.

Key words: acute lower respiratory tract infection, multiplex PCR, virus etiology