1. Public health risk assessment and epidemiology of acute contamination with Polonium 210 London, October-November 2006
Isabelle Giraudon,
Graham Fraser, Helen Maguire, Mike Bailey, George Etherington, Louise Bishop, Mike Youngman, Alan Johnson Sandra Cohuet, Sarah Forrester, Lucy Thomas, Ruth Ruggles, Deborah Turbitt, Roger Gross
APHA November 2007

2. Alert 23/10/2006 Alexander Litvinenko died in a London hospital
Alleged poisoning with Polonium-210 (210Po)
Criminal investigation launched
Concerns from a public health perspective
exposure through providing care
contamination of environment (risk of inhalation, ingestion)
primary source (residual)

3. 210Po Normally a solid metal Decays by emission of alpha particles
Dissolves to form salts
Decays by emission of alpha particles
Half-life 138 days
Remains detectable on surfaces
Possible to decontaminate
If ingested, inhaled or absorbed through a cut skin: potential for toxicity and acute radiation sickness

4. Objectives of the Agency response
Identify and support those potentially at risk
Prevent further risks to public health
Inform the people potentially exposed and the public
This presentation describes
The public health risk assessment
The epidemiology of exposure to 210Po

5. Investigation methods
Identification of potentially contaminated locations
Metropolitan Police
Environmental monitoring
Risk assessment of members of the public
stone in pond principle
site specific questionnaires
triage

6. Example of questionnaire: Hotels, Restaurants
For guests/visitors: date and duration of stay in contaminated rooms? in the bar?
For staff: places where they work e.g. rooms, bar; dates of work?
Nature of duties: e.g. cleaning toilets, rooms, service in room, bar waitress

7. Questionnaire for Health Care Workers
Q1. Were you involved in the care of the patient ?
Q2. Did you come into direct contact with urine, faeces, vomit, blood, or other body fluids ?
Q3. Were there occasions when you did not wear the standard personal protective equipment for the work you undertook ?
Q4. Have you been ill ? If YES, have you had any of the following: Nausea, vomiting, diarrhoea, fever, sore throat, bleeding, gums, unusual bleeding from cuts
YES to Q2: urine sample requested

8. Method contd 24 h urine sample urinary excretion measurement
milliBecquerel (mBq)/day
Epidemiological definition of acute exposure
>30 mBq/day
Dose assessment
milliSieverts (mSv)
No health concern if <6 mSv
Result fed back to the individual tested

9. Results: people at potential risk
10 London sites
2 hospitals
3 hotels
3 offices
2 restaurants
Family/friends/contacts of Mr. Litvinenko
1018 persons identified

10. Results of urine tests (n=752)
No evidence of internal contamination
<30mBq/day: %
Evidence of internal contamination
>30 mBq %
Dose assessment of 210Po
>6 mSv: %
1-6 mSv: %

11. Prevalence of internal contamination

12. Prevalence of internal contamination

13. Health care workers who provided urine sample – Barnet and UCL hospitals (n=78)

14. Reported contact with body fluids on skin and/or PPE (5/43 with >30 mBq/day)

15. Discussion
5 hospital staff with evidence of internal contamination did not report certain contact with body fluids on skin and/or PPE
No detailed exposure information collected initially
type, extent, intensity
No detailed information on PPE used (mask, gloves..)
Extended interviews and further studies ongoing

16. Millennium hotel Staff
Staff initial assessment
all staff working in early Nov
Pine Bar staff: RR 4.7 (1.8 – 13.0) p<0.05
2nd assessment:
extended to all staff and visitors who entered the Bar
Increased risk associated with dates and duration of stay in the bar

17. Millennium hotel Guests

18. Conclusion Large incident / pressure / little known at the beginning
Complex - variety of locations and potential risks
Deliberate. Public health implications could have been considerable
Most people had no evidence of contamination
Factors associated with contamination: confirmed some initial assumptions
Risk assessment based on PH principles
Pragmatic - not epidemiological study

19. Acknowledgements HPA Local and Regional Services
HPA Radiation Protection Division
HPA Health Protection Units
HPA Centre for Emergency Preparedness and Response
HPA Chemical Hazards and Poisons Division
HPA Centre for Infections
NHS Direct
Contacts
Web sites
Radiation Protection Division