title: Epidemiology of internal contamination with polonium-210 in the London incident, 2006.
abstract: BACKGROUND
  More than 700 UK residents were tested for possible contamination with polonium-210 ((210)Po) following the alleged poisoning of Mr Alexander Litvinenko in London in November 2006. This paper describes the epidemiology of internal contamination with the radionuclide in this group.
  
  
  METHODS
  11 locations in London had been identified as sufficiently environmentally contaminated with (210)Po to present a health risk to people associated with them. Public health consultant teams identified individuals at risk and offered 24-h urine testing for (210)Po excretion. Prevalence of internal contamination was estimated, and a retrospective cohort analysis was completed for each location.
  
  
  RESULTS
  Overall 139 individuals (prevalence 0.19 (95% CI 0.13 to 0.27)) showed evidence of internal contamination with (210)Po, although none with uptakes likely to cause adverse health effects. Substantial prevalence was seen among specific hotel service staff, customers, staff and other users of a hotel bar, office and hospital staff, staff of one restaurant and residents of and visitors to the family home. Increased risks of contamination were seen for a hotel bar in association with occupational, behavioural and temporal factors. Occupational and guest exposure to contaminated areas of hotels were also associated with increased contamination risk. Nurses were more likely to become contaminated than other staff involved in direct patient care.
  
  
  CONCLUSIONS
  Uptake of trace amounts of radionuclide in this incident was frequent. Occupational, behavioural and temporal gradients in contamination risk were mostly consistent with a priori site risk assessments. Utility of the investigation methods and findings for future accidental or deliberate environmental contamination incidents are discussed.
authors.affiliation: Health Protection Agency (HPA), 151 Buckingham Palace Road London SW1W 9SZ, UK. graham.fraser@ecdc.europa.eu
authors.forename: G
authors.initials: G
authors.lastname: Fraser
authors.forename: I
authors.initials: I
authors.lastname: Giraudon
authors.forename: S
authors.initials: S
authors.lastname: Cohuet
authors.forename: L
authors.initials: L
authors.lastname: Bishop
authors.forename: H
authors.initials: H
authors.lastname: Maguire
authors.forename: H L
authors.initials: HL
authors.lastname: Thomas
authors.forename: S
authors.initials: S
authors.lastname: Mandal
authors.forename: K
authors.initials: K
authors.lastname: Anders
authors.forename: E
authors.initials: E
authors.lastname: Sanchez-Padilla
authors.forename: A
authors.initials: A
authors.lastname: Charlett
authors.forename: B
authors.initials: B
authors.lastname: Evans
authors.forename: R
authors.initials: R
authors.lastname: Gross
mesh_terms: D015331:Cohort Studies; D004781:Environmental Exposure / Q000032:analysis; D004784:Environmental Monitoring; D016021:Epidemiologic Studies; D062665:Epidemiological Monitoring; D006708:Homicide; D006801:Humans; D008131:London / Q000453:epidemiology; D016273:Occupational Exposure / Q000032:analysis; D011041:Poisoning / Q000453:epidemiology*; D011059:Polonium / Q000652:urine*; D011633:Public Facilities; D012189:Retrospective Studies; D012306:Risk
chemical_list: D011059:Polonium