title: Does respiratory virus coinfection increases the clinical severity of acute respiratory infection among children infected with respiratory syncytial virus?
abstract: BACKGROUND
  Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory infection in children less than 5 years of age. The impact of non-RSV respiratory virus coinfection on the severity of RSV disease is unknown.
  
  
  METHODS
  This hospital-based prospective study was conducted in Nagasaki, Japan, on all children less than 5 years of age with acute respiratory infection (ARI) who had undergone a rapid RSV diagnostic test between April 2009 and March 2010. Thirteen respiratory viruses were identified from nasopharyngeal swab samples using a multiplex polymerase chain reaction; polymerase chain reaction-positive samples were considered as confirmed respiratory virus infections. The cases were classified into 3 categories (pneumonia, moderate-to-severe nonpneumonic ARI and mild ARI) according to the findings of the chest radiograph and the hospitalization records.
  
  
  RESULTS
  Among 384 cases enrolled, 371 were eligible for analysis, of whom 85 (23%) were classified as pneumonia cases; 137 (37%) as moderate-to-severe nonpneumonic ARI cases and 162 (40%) as mild ARI cases. RSV was detected in 172 cases (61.6%), and 31 cases (18.0%) had double or triple infections with other respiratory viruses. RSV infection was more frequently observed in pneumonia cases (odds ratio [OR]: 2.3; 95% confidence interval [CI]: 1.31-3.9) and moderate-to-severe nonpneumonic ARI cases (OR: 2.95; 95% CI: 1.82-4.78) than in mild ARI cases. The association with moderate-to-severe nonpneumonic ARI cases was stronger with RSV/non-RSV respiratory virus coinfection (adjusted OR: 4.91; 95% CI: 1.9-12.7) than with RSV single infection (adjusted OR: 2.77; 95% CI: 1.64-4.7).
  
  
  CONCLUSIONS
  Non-RSV respiratory virus coinfection is not uncommon in RSV-infected children and may increase the severity of RSV disease.
authors.affiliation: Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Sakamoto, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Harada
authors.forename: Fumiko
authors.initials: F
authors.lastname: Kinoshita
authors.forename: Lay Myint
authors.initials: LM
authors.lastname: Yoshida
authors.forename: Le Nhat
authors.initials: le N
authors.lastname: Minh
authors.forename: Motoi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Konosuke
authors.initials: K
authors.lastname: Morimoto
authors.forename: Yuichirou
authors.initials: Y
authors.lastname: Toku
authors.forename: Kunio
authors.initials: K
authors.lastname: Tomimasu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Moriuchi
authors.forename: Koya
authors.initials: K
authors.lastname: Ariyoshi
mesh_terms: D000208:Acute Disease; D016009:Chi-Square Distribution; D002675:Child, Preschool; D060085:Coinfection / Q000453:epidemiology / Q000821:virology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D016017:Odds Ratio; D011024:Pneumonia, Viral / Q000453:epidemiology / Q000821:virology; D011446:Prospective Studies; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000821:virology*; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000821:virology*; D014780:Viruses / Q000235:genetics / Q000302:isolation & purification