title: The source of respiratory syncytial virus infection in infants: a household cohort study in rural Kenya.
abstract: BACKGROUND
  Respiratory syncytial virus (RSV) vaccine development for direct protection of young infants faces substantial obstacles. Assessing the potential of indirect protection using different strategies, such as targeting older children or mothers, requires knowledge of the source of infection to the infants.
  
  
  METHODS
  We undertook a prospective study in rural Kenya. Households with a child born after the preceding RSV epidemic and ≥ 1 elder sibling were recruited. Nasopharyngeal swab samples were collected every 3-4 days irrespective of symptoms from all household members throughout the RSV season of 2009-2010 and tested for RSV using molecular techniques.
  
  
  RESULTS
  From 451 participants in 44 households a total of 15 396 nasopharyngeal swab samples were samples were collected, representing 86% of planned sampling. RSV was detected in 37 households (84%) and 173 participants (38%) and 28 study infants (64%). The infants acquired infection from within (15 infants; 54%) or outside (9 infants; 32%) the household; in 4 households the source of infant infection was inconclusive. Older children were index case patients for 11 (73%) of the within-household infant infections, and 10 of these 11 children were attending school.
  
  
  CONCLUSIONS
  We demonstrate that school-going siblings frequently introduce RSV into households, leading to infection in infants.
authors.affiliation: KEMRI- Wellcome Trust Research Programme, Kilifi, Kenya.
authors.forename: Patrick K
authors.initials: PK
authors.lastname: Munywoki
authors.forename: Dorothy C
authors.initials: DC
authors.lastname: Koech
authors.forename: Charles N
authors.initials: CN
authors.lastname: Agoti
authors.forename: Clement
authors.initials: C
authors.lastname: Lewa
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Cane
authors.forename: Graham F
authors.initials: GF
authors.lastname: Medley
authors.forename: D J
authors.initials: DJ
authors.lastname: Nokes
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005190:Family; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007630:Kenya / Q000453:epidemiology; D008297:Male; D009305:Nasopharynx / Q000821:virology*; D010802:Phylogeny; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000235:genetics / Q000302:isolation & purification*; D012424:Rural Population; D055815:Young Adult
keywords: RSV; households; infants; siblings; transmission