title: The epidemiology of paediatric intussusception in Singapore: 1997 to 2004.
abstract: BACKGROUND
  The world's first rotavirus vaccine, Rotashield or RRV-TV, was registered in the US in 1998, but withdrawn within a year because of an observed association with intussusception (IS). Surveillance for IS has consequently become important in safety monitoring of new-generation rotavirus vaccines during development. Post-marketing surveillance is also important, and requires the availability of local baseline epidemiology data on IS.
  
  
  METHODS
  An eight-year study of IS in children under 2 years of age in Singapore was performed by retrospective review of admissions to KK Women's and Children's Hospital, the main paediatric hospital, from 1997 to 2001, followed by prospective surveillance of all hospitals from 2001 to 2004, using the case definition of the Brighton Collaboration Intussusception Working Group.
  
  
  RESULTS
  The average IS incidence was 60 per 100,000 in under-ones, and 32 per 100,000 in under-twos, with a downward trend between 1999 and 2004. Ninety-two per cent of subjects were aged below one year, with 51% aged 6 months to 11 months. The mean age at which IS occurred increased from 6.4 months to 12.5 months over the study period. The male-to-female ratio was 1.3:1. No trend in IS numbers was observed over different months of the year.
  
  
  CONCLUSIONS
  IS in Singapore shows no seasonality, but has demonstrated a trend of decreasing incidence in recent years. While highest in the first year of life, the risk of IS is increasing in the second year of life. Males have a slightly higher risk.
authors.affiliation: GlaxoSmithKline Biologicals, Singapore. irving.boudville@gsk.com
authors.forename: Irving Charles
authors.initials: IC
authors.lastname: Boudville
authors.forename: Kong Boo
authors.initials: KB
authors.lastname: Phua
authors.forename: Seng Hock
authors.initials: SH
authors.lastname: Quak
authors.forename: Bee Wah
authors.initials: BW
authors.lastname: Lee
authors.forename: Htay Htay
authors.initials: HH
authors.lastname: Han
authors.forename: Thomas
authors.initials: T
authors.lastname: Verstraeten
authors.forename: Hans Ludwig
authors.initials: HL
authors.lastname: Bock
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007443:Intussusception / Q000139:chemically induced / Q000453:epidemiology*; D008297:Male; D011446:Prospective Studies; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012401:Rotavirus / Q000276:immunology*; D012400:Rotavirus Infections / Q000517:prevention & control*; D022243:Rotavirus Vaccines / Q000009:adverse effects*; D012846:Singapore / Q000453:epidemiology; D014611:Vaccination / Q000009:adverse effects*
chemical_list: D022243:Rotavirus Vaccines