title: The impact of viral dynamics on the clinical severity of infants with respiratory syncytial virus bronchiolitis.
abstract: The impact of dynamic respiratory syncytial virus (RSV) load on the clinical severity of hospitalized infants with bronchiolitis has not been clarified. Nasopharyngeal aspirates were obtained from 60 infants who were diagnosed with bronchiolitis within 96 hr of wheezing onset upon admission and on days 3, 5, and 7 in the hospital, and 17 respiratory viruses were detected. The RSV load was quantified by real-time qPCR for RSV subtypes A and B at different time points. Scoring criteria were used to evaluate the degree of severity. A total of 40 infants were determined to be RSV-positive, nine were identified as RSV subtype A (RSVA), and 31 were RSV subtype B (RSVB). The peak RSV load was observed upon admission, and the RSV load decreased significantly over time; in addition, this decrease began to have significant differences on day 5. There was a positive correlation between the RSV load and the clinical score (r(2)  = 0.121 and P < 0.001). According to the clinical scores, the infants in the severe group tended to have higher RSV loads than those in the moderate and mild groups. Multivariate logistic regression models revealed that the viral load on day 3 was independently associated with the degree of severity. This study elucidated that a higher mean RSV load was associated with a more severe disease and a longer duration of hospitalization and symptoms. This study also clarified RSV replication in infants and provides a theoretical basis for specifying an anti-RSV therapy strategy.
authors.affiliation: Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.|Key Laboratory of Pediatrics in Chongqing CSTC2009CA5002, Chongqing, China.|Department of Respiratory Medicine, Women and Children's hospital, Ganzhou, Jiangxi, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.|Key Laboratory of Pediatrics in Chongqing CSTC2009CA5002, Chongqing, China.
authors.forename: Qiuyan
authors.initials: Q
authors.lastname: Xiao
authors.affiliation: Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.|Key Laboratory of Pediatrics in Chongqing CSTC2009CA5002, Chongqing, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Molecular Biology of Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, China.
authors.forename: Ailong
authors.initials: A
authors.lastname: Huang
authors.affiliation: Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.|Key Laboratory of Pediatrics in Chongqing CSTC2009CA5002, Chongqing, China.
authors.forename: Luo
authors.initials: L
authors.lastname: Ren
authors.affiliation: Department of Respiratory Medicine, Children's Hospital, Chongqing Medical University, Chongqing, China.
authors.forename: Enmei
authors.initials: E
authors.lastname: Liu
mesh_terms: D001988:Bronchiolitis / Q000473:pathology* / Q000821:virology*; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction; D018357:Respiratory Syncytial Virus Infections / Q000473:pathology* / Q000821:virology*; D012136:Respiratory Syncytial Viruses / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012720:Severity of Illness Index; D019562:Viral Load
keywords: RSV load; bronchiolitis; clinical severity; infants; time points