title: [Monitoring of influenza virus B and clinical features of pediatric pneumonia caused by influenza virus B only].
abstract: OBJECTIVE
  To investigate the epidemiological features of influenza virus B (IVB) in the winter and the clinical features of pediatric pneumonia caused by IVB only.
  
  
  METHODS
  A retrospective study was performed on the clinical data of children with respiratory infection who received pathogen testing and therapy at Soochow University Affiliated Children's Hospital during the winters of 2008, 2009, 2010 and 2011.
  
  
  RESULTS
  The positive rates of influenza viruses A and B in the winters of 2008, 2009, and 2010 were 0.89%, 5.49%, and 6.24% respectively; the positive rate of influenza viruses A and B in the winter of 2011 was 8.72%, significantly higher than those in 2008-2010. The positive rates of IVB in the winters of 2008, 2009, and 2010 were 0%, 0%, and 0.21% respectively; the positive rate of IVB in the winter of 2011 was 5.36%, which was significantly higher than in the years 2008 to 2010. Pneumonia caused by IVB was confirmed in 94 children during the winter of 2011, including 27 cases of pneumonia caused by IVB only. Most of children with pneumonia caused by IVB only were aged over 6 months. The common symptoms in the 27 children caused by IVB only were fever (85%), runny nose (89%), and cough (100%). Wheezing (26%) and dyspnea (7%) were also seen in some cases. Among the 27 children, 19% showed abnormal white blood cell count, 30% showed increased C-reactive protein, 70% showed decreased prealbumin, and none showed visible organ dysfunction. No specific imaging findings were seen in the children with pneumonia caused by IVB only. However, many abnormal humoral and cellular immunological parameters were found in the majority of these children. The average length of hospital stay was approximately one week, there were no critical patients and the prognosis was good.
  
  
  CONCLUSIONS
  Influenza viruses were at a peak level in inpatient children in the winter of 2011. IVB infection rate was gradually increasing. In children with pneumonia caused by IVB only, there are few critical patients, the symptoms are nonspecific and the prognosis is good.
authors.affiliation: Department of Emergency, Children's Hospital Affiliated to Soochow University, Suzhou, Jiangsu 215003, China. zhwlin@126.com
authors.forename: Jun
authors.initials: J
authors.lastname: Hua
authors.forename: Xiao-Chen
authors.initials: XC
authors.lastname: Du
authors.forename: Min-Hui
authors.initials: MH
authors.lastname: Xie
authors.forename: Xue-Lan
authors.initials: XL
authors.lastname: Zhang
authors.forename: Yun-Fang
authors.initials: YF
authors.lastname: Ding
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009981:Influenza B virus; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D007902:Length of Stay; D008297:Male; D011024:Pneumonia, Viral / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D012189:Retrospective Studies