Insights into Outbreak Management. David Looke Princess Alexandra Hospital Woolloongabba, 4102

Transcription

1 Insights into Outbreak Management David Looke Princess Alexandra Hospital Woolloongabba, 4102

2 Hippocrates first coined the term epidemic (έπίδήμον epi~ upon + demos~ the people) in relation to disease in his 430BC treatise epidemics )

3 Other terms used through the ages have been used interchangeably such as plagues, scourges, pestilence

4 By the end of the 19 th century the word epidemic was being used strictly in the sense of an outbreak of a disease caused by a single genus and species of microbe Emerging Infectious Diseases :

5 EPIDEMIC an epidemic occurs when new cases in a given human population, during a given period, substantially exceed what is "expected," based on recent experience In recent usages, the disease is not required to be communicable.

6 Pandemic A pandemic (πανδήμος) is an epidemic of infectious disease that spreads through populations across a large region; for instance a continent, or even worldwide.

7 By the 21 st Century however:

8 By the 21 st Century however: Epidemic of obesity

9 By the 21 st Century however: Epidemic of obesity Health politics

10 By the 21 st Century however: Epidemic of obesity Health politics Heavy Metal

11 By the 21 st Century however: Health politics Epidemic of obesity Heavy Metal Rock Concert

12 So health professionals now favour the term outbreak

13 Outbreak Outbreak describes an occurrence of disease greater than would otherwise be expected in a particular time and place. It may be a small and localized group or impact upon thousands of people across an entire continent. Two linked cases of a rare infectious disease may be sufficient to constitute an outbreak. Outbreaks may also refer to epidemics which affect a region in a country or a group of countries,

14 Outbreak : is the name of a 1995 film. is the name of a novel by Robin Cook. Resident Evil: Outbreak is a video game. is a hardcore/thrash band from Maine noted for their short, angry songs.

15 Outbreaks can occur: in the community in healthcare facilities amongst animals (epizootics) And move between animals and humans

16 Outbreaks Have driven the understanding of many infectious diseases Are often exciting and have been the stimulus for many to take up careers in infectious diseases, microbiology, science and public health Have driven the development of public health law Have been the making and breaking of individual careers

17 The science of epidemiology was developed as a rational response to problems with outbreak diseases

18 A search on Embase for the term outbreak and the years 2002 to 2012 found 20,087 entries Nosocomial infection+ outbreak found 1,161

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25 What should be the approach to managing an outbreak? Community Healthcare facility

26 Approach to Outbreak Management Well recognised process In most texts on epidemiology Plant A, Watson C. Communicable Disease Control. IP Communications Melbourne 2008 Gregg MB. Field Epidemiology. Oxford Uni Press, New York 2002 Ostrowsky B, Jarvis W. Efficient management of Outbreak Investigations. In: Wenzel RP. Prevention and Control of Nosocomial Infections. Lippincott W&W Philadelphia 2003 Oleckno WA. Epidemiology: Concepts and Methods. Waveland Press Illinois 2008 On line training programs with CDC Epi-info software originally designed to support a scientific approach to outbreak management Epi-data now from Denmark

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33 Examples of Various Types of Healthcare-related Outbreaks S pyogenes SSIs Haemodialysis pyrogenic reactions BSIs in ICUs B cepacia pseudo-infection C albicans BSIs Y enterocolitica BSIs Gram ve pneumonias G-ve BSIs Nosocomial MDR TB Legionnaires disease Surgical staff carrier Contaminated dialysate Contaminated pressure transducers Blood gas machines Contaminated TPN solution Contaminated packed cells Contaminated nebulisers Contaminated water for injection Inadequate respiratory isolation Contaminated air handling equipment Adapted from: Beck-Sague C et al. Outbreak Investigations. A Practical Handbook for Hospital Epidemiologists. SHEA 2004

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36 Verify the diagnosis related to the outbreak Identify the existence of the outbreak: is the group of ill persons normal for the time of year, geographic area, etc.? Create a case definition to define who/what is included as a case Describe outbreak with respect to time, place, and people Develop a hypothesis: what appears to be causing the outbreak? Study hypothesis: collect data and perform analysis Refine hypothesis and carry out further study Develop and implement control and prevention systems Release findings to greater community CDC Guidelines for investigating outbreaks

37 Outbreaks in Healthcare How are outbreaks detected? Routine surveillance Standardized definitions Statistical analysis of trends Control charts Sufficient numbers required for routine analysis Syndrome based surveillance Clinical suspicion medical nursing lab. Staff regular examination of microbiology or QA records

38 Surveillance Problems in Hospitals Random events often appear to be in clusters Statistical methods required to ascertain significance (95% CI, p <0.05) Numbers in individual hospitals usually too small for meaningful analysis Qualitative methods are probably far more valuable

39 Cardiac Surgery Coronary artery bypass graft: sternal wound Year IH % 95% CI PD % 95% CI Complex % 95% CI / / / / / / / / / / / / / / / / / * 20/ / / / / / *2009 onwards - only Post Discharge Complex infections were recorded as Post Discharge Infections

40 Cumulative O - E PAH Complex SSI - Cardiac CABG Cumulative O - E and CUSUM chart from 01Jan08 to 31Dec10. 01Jan08 25Feb08 17Apr08 05Jun08 18Jul08 09Sep08 10Nov08 06Jan09 24Feb09 16Apr09 18Jun09 14Aug09 09Oct09 02Dec09 09Feb10 13Apr10 03Jun10 10Aug10 26Oct10 21Dec10 Observed Blue, 95% Limits Red, Arrows CUSUM Signals, Tick Marks Every 50 Units. Signals on 12-Nov-2008

41 Outbreak Investigations The recommended steps are logical BUT They should in general be enacted in parallel, the object being to prevent new cases as soon as possible Temporary control measures should always be taken as a matter of urgency It is now much more unacceptable to do too little rather than too much

42 Outbreak Investigations The recommended steps are logical BUT They should in general be enacted in parallel, the object being to prevent new cases as soon as possible Temporary control measures should always be taken as a matter of urgency It is now much more unacceptable to do too little rather than too much

43 Outbreak investigation 1. Confirm the presence of an outbreak no pseudo-outbreak 2. Establish a case definition Clinical Laboratory 3. Ask the 6 key Questions

44 I keep six honest serving men. (They taught me all I know); Their names are WHAT and WHY and WHEN and HOW and WHERE and WHO. Rudyard Kipling. Just So Stories

45 What is the disease? Who is affected? When did it start (and finish)? Where is it happening? How did it start? Why did it happen?

46 Outbreak investigation 4. Plot the epidemic curve and the geographic area involved the shape of the curve can suggest the source and mode of spread Is it is a true outbreak? current rates are higher than past rates

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48 The Original Outbreak of Legionella pneumophila pneumonia

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50 Equine Influenza 2008

51 O-96 N-96 D-96 J-97 F-97 M-97 A-97 M-97 J-97 J-97 A-97 S-97 O-97 N-97 D-97 J-98 F-98 M-98 A-98 M-98 J-98 J-98 A-98 S-98 O-98 N-98 D-98 J-99 F-99 M-99 A-99 M-99 J-99 J-99 A-99 S-99 O-99 N-99 D Epidemic Curve of PAH VRE Isolates Bartley P et al J Hosp Infect A-0 A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 B-0 C-0 D-0 E-0 F-0 G-0 G-1 H-0

52 Gantt charts arise from project planning and are a visual representation of coordinated scheduling They can be adapted to outbreak visualisation and allow a visual display of the subjects and their temporal and spatial relationship Gantt Charts

53 Eurosurveillance (33): 21 August

54 Gantt display of temporal patterns of gastroenteritis outbreaks. The varying shades of blue background represent hospitals within each NHS trust and each horizontal line represents an inpatient unit. Blue sections are 'outbreak-free periods' and orange sections are 'outbreak periods' (from the 1st to the last date of onset). A high degree of temporal clustering can be observed in all Trusts. In other words, outbreaks do not often appear in isolation but rather many units are affected sequentially. Lopman et al. BMC Infectious Diseases :108 doi: /

55 Characterised norovirus outbreaks in two hospitals in Avon England April 2002 to March Each row depicts the follow-up of a single hospital unit. Colored bars represent the period between the onset of illness in the first and last case in an outbreak where norovirus was characterised. Each unique norovirus sequence is represented by a different color. Series of outbreaks meeting the definition of a cluster are circled and were tested for statistical significance. Lopman et al. BMC Infectious Diseases :108

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58 Outbreak investigation 5. Literature Review no point in reinventing the wheel

59 Outbreak investigation 6. Formulate hypothesis about source and mode of spread 7. Set up appropriate communications Notify: infection control committee members mangers, directors, administration in general. clinicians, ward staff public health unit microbiology lab. Media liaison

60 Outbreak investigation 8. Consider setting up outbreak management team Always if children or animals involved You may consider going it alone, but it is generally better to share the fame so you can spread the blame 9. Keep a record (diary) of events

61 Outbreak investigation 10.Institute temporary control measures Ward closure and isolation Withdrawal of a product Cessation of surgery Screen and isolate Multi-modal approach eg for MRSA outbreak

62 Outbreak investigation 11. Confirm hypothesis by using appropriate epidemiological tool Observational study case control study cohort study 12. Confirm source/ reservoir and mode of transmission microbiologically May need molecular strain typing Molecular techniques to define a novel agent Demonstration of biological plausibility

63 Case-Control Study Design exposed not exposed exposed not exposed Cases (+ disease) Controls (- disease) Defined Population TIME Direction of inquiry

64 Recognition of this outbreak was by follow up of BSIs in the wards and recognising a pattern in patients who had none of the usual other risk factors or sources of a Gram-negative infection Multiple different organisms were involved (Serratia, Acinetobacter, Pseudomonas) The hypothesis of contaminated giving sets and asynchronous line/ giving set changes was tested with a mock setup Behaviour change was attempted (Simultaneous line and syringe pump changes), but failed to prevent cases New technology was required (preloaded syringes with lines attached) Biological Plausibility

65 Recognition of this outbreak was by follow up of BSIs in the wards and recognising a pattern in patients who had none of the usual other risk factors or sources of a Gram-negative infection Multiple different organisms were involved (Serratia, Acinetobacter, Pseudomonas) The hypothesis of contaminated giving sets and asynchronous line/ giving set changes was tested with a mock setup Behaviour change was attempted (Simultaneous line and syringe pump changes), but failed to prevent cases New technology was required (preloaded syringes with lines attached) Biological Plausibility

66 Outbreak investigation 13. Update control measures by appropriate change of policies and procedures 14. Document efficacy of control measures with continued surveillance 15. Write a report

67 Outbreak investigation Bask in reflected glory with: Paper accepted for Nature invitations to speak at conferences membership of government committees Personal Chair endowed Big pay rise

68 Outbreak investigation OR suffer the effects of coronial inquiries, litigation, acrimony, sideways promotion and stress.

69 Outbreaks: Other issues and situations Legal dimensions The Health act: does its new provisions apply to healthcare facilities? Litigation? Who has duty of care? Infection control duty of care? The increasing demand for inquiry by external investigators Should hospitals investigate their own problems? Public trust?

70 Legal issues to overcome when dealing with an outbreak in the community Is this situation a public health emergency? Can we declare a public health emergency? Can we examine and test people? Can we treat and vaccinate people? Can we share information? Can we isolate/quarantine people? Can we force evacuation? Can we obtain facilities and supplies? Can we use non-government personnel? Are we liable? Who pays for expenses related to the emergency? How is a public health emergency terminated? Adapted from: legal issues and outbreak control CDC

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73 Outbreaks: Other issues and situations Community Outbreaks When they involve your hospital Highly contagious disease eg SARS Diseases that little is known about eg Hendra Staff anxiety Having to be the front man for government decisions even only a small number of infected patients may cause serious consequences for many, including threats to livelihood, liberty and life

74 SARS

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77 COSTS SARS IN CANADA Tourism $200-$350M Lost jobs 5250 Airline industry $220M Tax revenue $161M Non-tourism retail sales $380M Provincial health system >$1B Deferred medical care Exhausted health workers Impact on health care education Slides courtesy of Dr David Mowat

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82 Conclusion Outbreaks are common in healthcare Their timing is usually least convenient Recognition can be a problem A process for managing them is well established The literature is an excellent resource that should be consulted early Early and widespread communication is strongly recommended It is far worse to do too little than too much

83 Those who cannot learn from history are doomed to repeat it. George Santayana ( ) History is merely a list of surprises. It can only prepare us to be surprised yet again. Kurt Vonnegut

84 Acknowledgements: Brad McCall Anthony Morton Margaret Lindsay