1. Effect of Public Health Measures Results of the Pandemic Influenza Preparedness Model InfluSim Markus Schwehm, Martin Eichner ExploSYS GmbH, Tübingen, Germany Department of Medical Biometry, University of Tübingen, Germany

2. 1)What is pandemic preparedness all about? 2)Introduction to the program InfluSim 3)Influence of important parameters 4)Antiviral treatment and social distancing 5)Dealing with parameter insecurity 6)Work load of health care workers What we will talk about

3. - delay the epidemic peak to win time (waiting for the vaccine) - reduce the peak of the epidemic - minimize the total number of... (what exactly?) What is pandemic preparedness all about?

4. mass vaccinations? - probably not do much good with the existing vaccines What can we do? use of antivirals - treat cases - prophylaxis reduce contacts - (partial) isolation of cases - general behaviour changes - cancelling of events of mass gathering - closing day care centres and schools - travel restrictions ?

5. InfluSim - a planning tool for pandemic influenza preparedness www.influsim.info

6. Multilingual InfluSim

7. Influenza dynamics S susceptible age risk E infected risk age V very sick age W u untreated age H t treated hospit. age W t treated age H u untreated hospit. age X extremely sick age M moderately sick age A asymptomatic age R reconvalescent age D dead age I recovered and immune age

8. Influence of important parameters Project with Bundesgesundheitsamt (BAG) Bern Switzerland +

9. Influence of important parameters basic reproduction number R 0 time-specific contagiousness population size =100 000

10. Project with Landesgesundheitsamt (LGA) Baden-Württemberg Stuttgart, Germany Antiviral treatment and social distancing

11. Effect of antiviral treatment stockpile duration of intervention

12. Limited availability of antiviral drugs

13. Reducing social distance Outpatients per 100,000 curves of increasing social distancing duration of intervention

14. Project with Bundesgesundheitsamt (BAG) Bern Switzerland Dealing with parameter insecurity +

15. For up to 10 parameters, random values were chosen in given ranges. Population size = 100 000 Results of 50 000 simulations are given. dark: low R 0 light: high R 0

16. Project with Bundesgesundheitsamt (BAG) Bern Switzerland Closing schools and day care centers +

17. Contact matrix and contact redistribution

18. School closing results Closing of daycare centers can reduce the cases of 0-5 year old children by up to 5%. Closing of schools can reduce the cases by up to 17.3% (6-12 year old) and by up to 13.8% (13-19 year old), respectively. Closing of day care centers can be disadvantageous for older age groups, especially for adults. Closing of daycare centers and schools has only a small effect on the total number of severe cases in an influenza pandemic.

19. Work load of health care workers (HCW) Project with Landesamt für Gesundheit und Lebensmittelsicherheit (LGL) Oberschleißheim Munich, Germany

20. Work load of health care workers (HCW) Standard workload (patients / HCW) is set to 100% The work load increases because of –additional hospitalizations due to flu –flu-related work loss among HCW The work load of HCW can be reduced by –treating HCW prophylactically –temporarily sending home some of the non-flu patients

21. Antiviral prophylaxis... is offered to HCW in a given time window... is only given as long as antiviral drugs are available (competition with treatment of severely sick cases!)... has the effect to –reduce susceptibility (by 50%) –reduce contagiousness (by 80%) –reduce duration of disease (by 25%) –reduce the severity of disease (not in the current InfluSim release)

22. Work load of HCW working HCW sick HCW additional beds occupied by flu patients work load of HCW during the epidemic Prophylaxis

23. Conclusions Interventions must be implemented as soon as possible and should not be discontinued before the epidemic is over Antiviral treatment and social distancing should be combined (this also helps to reduce the necessary size of the stockpile) Strong interventions in the very beginning can delay the peak of the outbreak and help to win time Antiviral prophylaxis of HCW reduces the work load of HCW, but may increase the total size of the epidemic if antiviral drugs are limited