title: Molecular epidemiology of respiratory syncytial virus transmission in childcare.
abstract: BACKGROUND
  Respiratory syncytial virus (RSV) is the most important cause of serious respiratory infections in young children. No prior studies using molecular techniques to examine RSV transmission in the community childcare setting have been performed.
  
  
  OBJECTIVE
  We seek to characterize the molecular epidemiology of RSV transmission in childcare to evaluate the impact of RSV disease in a community-based population.
  
  
  METHODS
  We sequenced RSV-positive nasopharyngeal samples from a prospective longitudinal study of respiratory illnesses among children enrolled in childcare during three winter seasons. Phylogenetic analysis was performed to identify unique viral strains.
  
  
  RESULTS
  RSV was detected in 59 (11%) illnesses. Compared to RSV-negative illnesses, RSV-positive illnesses were associated with longer symptom duration and increased frequency of health care visits. Another respiratory virus was detected in 42 (71%) RSV-positive illnesses. RSV viral load did not differ between RSV-positive illnesses with and without another respiratory virus identified (P = 0.38). In two childcare rooms, 50% of the children had RSV detected within six days of the first case. Five (38%) of 13 illness episodes from one childcare room were sequenced and shown to be the same viral strain, suggesting rapid child-to-child transmission within the room over a 16 day period.
  
  
  CONCLUSIONS
  RSV is rapidly transmitted within childcare. Childcare facilities may serve as ideal sites for evaluation of new prevention strategies given the high burden of RSV disease in this population and the rapidity of RSV spread between children.
authors.affiliation: Department of Medicine, University of Washington, Seattle, WA, USA. helenchu@uw.edu
authors.forename: Helen Y
authors.initials: HY
authors.lastname: Chu
authors.forename: Jane
authors.initials: J
authors.lastname: Kuypers
authors.forename: Christian
authors.initials: C
authors.lastname: Renaud
authors.forename: Anna
authors.initials: A
authors.lastname: Wald
authors.forename: Emily
authors.initials: E
authors.lastname: Martin
authors.forename: Mary
authors.initials: M
authors.lastname: Fairchok
authors.forename: Amalia
authors.initials: A
authors.lastname: Magaret
authors.forename: Misty
authors.initials: M
authors.lastname: Sarancino
authors.forename: Janet A
authors.initials: JA
authors.lastname: Englund
mesh_terms: D000293:Adolescent; D002648:Child; D002654:Child Care / Q000706:statistics & numerical data*; D002656:Child Day Care Centers / Q000706:statistics & numerical data*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D058749:Military Facilities / Q000706:statistics & numerical data; D017720:Molecular Epidemiology; D009305:Nasopharynx / Q000821:virology; D010802:Phylogeny; D011446:Prospective Studies; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D018113:Respiratory Syncytial Virus, Human / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D012307:Risk Factors; D012621:Seasons; D014861:Washington / Q000453:epidemiology