Abstract：
Respiratory syncytial virus (RSV) is the main pathogen that causes hospitalization for acute lower respiratory tract infections (ALRIs) in children. With the reopening of communities and schools, the resurgence of RSV in the COVID-19 post-pandemic era has become a major concern. To understand the circulation patterns and genotype variability of RSV in Tianjin before and during the COVID-19 pandemic, a total of 19,531 nasopharyngeal aspirate samples from hospitalized children in Tianjin from July 2017 to June 2022 were evaluated. Direct immunofluorescence and polymerase chain reaction (PCR) were used for screening RSV-positive samples and subtyping, respectively. Further analysis of mutations in the second hypervariable region (HVR2) of the G gene was performed through Sanger sequencing. Our results showed that 16.46% (3215/19,531) samples were RSV positive and a delayed increase in the RSV infection rates occurred in the winter season from December 2020 to February 2021, with the average RSV-positive rate of 35.77% (519/1451). The ON1, with H258Q and H266L substitutions, and the BA9, with T290I and T312I substitutions, are dominant strains that alternately circulate every 1-2 years in Tianjin, China, from July 2017 to June 2022. In addition, novel substitutions, such as N296Y, K221T, N230K, V251A in the BA9 genotype, and L226I in the ON1 genotype, emerged during the COVID-19 pandemic. Analysis of clinical characteristics indicated no significant differences between RSV-A and RSV-B groups. This study provides a theoretical basis for clinical prevention and treatment. However, further studies are needed to explore the regulatory mechanism of host immune responses to different lineages of ON1 and BA9 in the future.
摘要：
呼吸道合胞病毒（RSV）是导致儿童急性下呼吸道感染（ALRIs）住院的主要病原体。随着社区和学校的重新开放，在COVID-19大流行后时代，RSV的死灰复燃已成为一个主要问题。了解COVID-19流行前和流行期间天津市RSV的循环模式和基因型变异性，对2017年7月至2022年6月天津市住院儿童的19,531份鼻咽抽吸物样本进行了评价.直接免疫荧光和聚合酶链反应(PCR)用于RSV阳性样本的筛选和分型。分别。通过Sanger测序对G基因的第二高变区(HVR2)中的突变进行进一步分析。我们的结果显示，从2020年12月到2021年2月的冬季，16.46%(3,215/19,531)的样本为RSV阳性，RSV感染率延迟增加，平均RSV阳性率为35.77%(519/1,451)。具有H258Q和H266L取代的ON1，和BA9，用T290I和T312I替换，是天津每1-2年交替传播的优势菌株，中国,从2017年7月到2022年6月。此外,新颖的替换,如N296Y，K221T,N230K,V251A在BA9基因型，和L226I在ON1基因型，在COVID-19大流行期间出现。临床特征分析表明RSV-A和RSV-B组之间无明显差异。本研究为临床防治提供了理论依据。然而,未来还需要进一步研究探讨宿主对不同谱系ON1和BA9免疫应答的调控机制。
