1 / 43

The Next Pandemic

The Next Pandemic. Brian J Ward MDCM McGill Center for Tropical Diseases McGill Division of Infectious Diseases. Overview of Talk. • Infectious agents spread by respiratory route • Classification & pandemic potential • Influenza A • Pandemic Influenza A • SARS

tiana
Download Presentation

The Next Pandemic

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Next Pandemic Brian J Ward MDCM McGill Center for Tropical Diseases McGill Division of Infectious Diseases

  2. Overview of Talk • Infectious agents spread by respiratory route • Classification & pandemic potential • Influenza A • Pandemic Influenza A • SARS • Canadian ‘Readiness’ & Emergency Response

  3. Organisms Spread by the Respiratory Route Viruses (true airborne vs aerosol vs fomite) Adenoviridae Coronaviruses (SARS, common cold) Enteroviridae (poliomyelitis, Echo & Coxsackie) Herpesviridae (VZV) Myxoviridae (influenza viruses A, B and C) Paramyxoviridae (measles, mumps, RSV, PIV1-4) Pox viruses (smallpox) Rhinoviridae (common cold) … some hemorrhagic fever viruses (Junin, Lassa, CCF) … rabies virus … Bacteria Encapsulated (S. pneumonia, H. influenzae, N. meningitidis) Intracellular (Listeria, Mycoplasma, Chlamydia, Rickettsia) Granuloma-forming (Mycobacteria, brucellosis, meliodosis) Others (Bordatella), rare (tularemia, anthrax) & opportunists (Moraxella) Fungi Pneumocystis carinii Cocciodomycosis imitis, Cryptococcus neoformans Others (eg: Aspergillus)

  4. Organisms with Pandemic Potential Factors the Influence Pandemic Risk R0Reproductive rate Number of secondary cases generated by primary case in a susceptible population Timing of Transmission The proportion of transmission that occurs prior to the the development of obvious symptoms TgDisease generation time Time between the infection of one person and the next in a chain of transmission

  5. Reproduction Number (R0)Asymptomatic Transmission () Fraser C et al. Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):6146-51

  6. Classification of Organisms Biohazard Safety Level and Pandemic Impact BSL 1 Low group/individual risk Healthy subjects unlikely to contract illness (E.coli) BSL 2 Moderate individual risk/Limited group risk Causes disease - exposure unlikely to be serious (eg: measles) BSL 3 High individual risk but limited group risk Usually causes serious disease (eg: F. tularensis) BSL 4 High individual and community risk Likely to cause severe disease, usually not treatable (MDR TB)

  7. Influenza A

  8. Influenza A: The facts • Influenza A virus ‘shared’ - humans, birds, pigs (& other species) • Two proteins critical for immune response - hemagglutinin (H) - neuroaminidase (N) • Humans: 3 H types and 3 N types • Birds: > 13 H and 9 N types • Genes for H and N readily mutate • Genes segregate independently Genetic Drift Changes season-to-season Genetic Shift Changes that cause pandemics

  9. Influenza Morbidity & Mortality Non-Pandemic Years Attack Rates (/1000) (LR) 33 - 40 (HR) 62 - 116 Hospitalization Rates (LR) 0.6 - 1.3 (HR) 2 - 6.1 Deaths (LR) .0015 - 0.57 (HR) .0015 - 0.57 Schopflocher DP et al. Ann Epidemiol 2004; 14: 73-76 MMWR 2000

  10. Influenza Morbidity & Mortality Pandemic Year (Based on CDC FluAid Program) Arrival of pandemic strain in Canada 1-5 weeks Peak infection rates 4-6 months Attack rates ≥ 25% Outpatient Disease Rates (/1000) (LR) 60 - 198 (HR) 104 - 346 Hospitalization Rates (LR) .5 - 2.5 (HR) 2.9 - 8.5 Deaths (LR) 0.24 - .42 (HR) 0.22 - 4.2 Health Canada Pandemic Planning Committee Schopflocher DP et al. Ann Epidemiol 2004; 14: 73-76

  11. Genetic Shift - Pandemic Influenza Human Strains Unknown Avian Strains Potential to ‘mix & match’ avian & human strain genes Unknown

  12. subversity.blogspot.com

  13. Pandemic Influenza • Arise due to Genetic Shift • Humans immunologically ‘naïve’ • 2-3 pandemics per century Year Interval(yrs) Subtype Severity 1889 -- H3N2 moderate 1918 29 H1N1 severe 1957 39 H2N2 severe 1968 11 H3N2 moderate 1977 9 H1N1 mild

  14. Pandemic Without Vaccine In Canada, if vaccine is unavailable,EXPECT: • 11,000 to 58,000 (~1%) deaths • 34,000 to 138,000 hospitalizations • 2 to 5 million outpatients • economic costs • health care: $330M to $1.4B • societal: $5B to $38B Health Canada Pandemic Planning Committee

  15. Avian Influenza 2003-2004

  16. H5N1 Viruses • Variably pathogenic in birds • Emerged in Hong Kong 1997-98 • As yet unexplained hyper-mutation since them • Re-emerged in all of Asia 2003-04 • Limited capacity to ‘jump’ to humans • ? human-to-human spread documented (n=1) • ~60% mortality (young and healthy) • Recent evidence of infection in cats & pigs

  17. Influenza Vaccines • Whole inactivated virion • ‘Split’-virus • egg protein content • thimerosal • Cold-adapted, live virus (FluMist™) • Experimental vaccines - Proteosome (FluINsure™) - ISCOM-based - DNA, vectored, other

  18. Vaccine Production Efforts • Surveillance 110 national influenza labs 4 regional reference centres • Generation of seed-strains adapted to growth in eggs (eg: PR8) • Distribution of seed-strains to manufacturers • Two, 6-month cycles ~250x106 doses (10-20 doses/egg) Gerdil C. Vaccine 2003 www.alphaweb.org/docs/TAM_Teleclass_Pandemic_ Influenza_Local_MOHs_21Oct_2003-06_10_2003-11_36_37.ppt

  19. Issues with Current Vaccines • Egg-based Production - delays in adapting strains to eggs - problems with scale-up in the event of a pandemic - egg allergy • Side-Effects - Guillain-Barré Syndrome (~1:1x106 in some years) - Oculo-Respiratory Syndrome (ORS) •  PandemicVaccine Supply - borders may close to product movement • Immune Response toPandemic Strain - anticipate low antigenicity: may need two doses Prevalence 0.13 - 1.6% Higher in young children Highest in kids with allergies (3-40%) Zeigler RS. J Allergy Clin Immunol 2002;110:834

  20. Other concerns • Pattern of Pandemic - Big ‘bang’ - Grumble then explode • Anti-viralDrug Stockpiles - Resistant organisms - Priority list for distribution • Who is ‘in charge’? - FPT committee nominally in control - BGTD controls licensing - ? access to drugs/vaccine - graded travel advisories

  21. SARS

  22. 2003 Epidemic/Pandemic

  23. • early index case with diarrhea • lived on top floors • subsequent cases on same ‘side’ of complex • ‘leak’ in sewage pipes so feces dried on pipes and blown into building Epidemiology - Amoy Gardens • Amoy Gardens Appartment Complex (Hong Kong) • 131 cases of SARS (block E residents) • 241 asymptomatic residents quarantined • ariborne, droplet, water, environmental (cockroaches), etc

  24. There are only 3 certainties in life ... • Death • Taxes • That rents have gone down at the Amoy Gardens Apartment Complex

  25. Etiology, Reservoir & Mortality • electron microscopy = coronavirus • civet cat = ? only reservoir • initial mortality estimates 2-8% • recent WHO estimate 20-50% • Hospital-based outbreak (CDN) will increase estimate • Even if 2% is true estimate 2% of 5x10 = 1x10 deaths 9 8

  26. Clinical Disease - Imaging Wong KT, et al. Severe Acute Respiratory Syndrome: Radiographic Appearances and Pattern of Progression in 138 Patients. Radiology. 2003 May 20 55-year-old healthy man with history of recent travel to Hong Kong. AP showing extensive bilateral ground-glass Opacities and poorly defined nodular pattern. 12 hours later Nicolaou S et al. AJR Am J Roentgenol. 2003;180:1247-9

  27. Will the Next Outbreak be Controllable? Influenza Smallpox HIV SARS Fraser C, Riley S, Anderson RM, Ferguson NM. Factors that make an infectious disease outbreak controllable. Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):6146-51

  28. Infections with the Potential to Shape our World • HIV • Influenza virus • N meningitidis • Ebola (Reston) • Hendra & Nipah viruses • Prions (vCJD)

  29. The Hajj • Religious obligation • 1.8 million (2001) - 63% Arab countries - 30% non-Arab Asia - 5% other African - 2% other • Al Haram - 356,000 sq meters - 1 million pilgrims • Madinah - 165,000 sq meters - 750,000 pilgrims • Meningococcal epidemics (carriage as high as 80%) • 2000 Spread of W135 serotype around globe

  30. Issues, What Issues? Health SantéCanada Canada

  31. Global Agenda for Influenza Surveillance and Control (WHO) Major Themes 1. Improvement in the quality and coverage of virological and epidemiological influenza surveillance 2. Improvement in the understanding of health and economic burden of influenza, including benefits from epidemic control and pandemic preparedness

  32. Global Agenda for Influenza Surveillance and Control (WHO) Major Themes 3. Expansion in the use of existing vaccines, particularly in developing countries and in high-risk groups and acceleration in the introduction of new vaccines 4. Increase in national and global epidemic and pandemic preparedness, including vaccine and pharmaceutical supplies

  33. WHO Pandemic Phases Phase 0, Level 0 - Inter-Pandemic period Phase 0, Level 1 - Novel virus identification in a human Phase 0, Level 2 - Human infection confirmed Phase 0, Level 3 - Human-to-Human transmission confirmed Phase 1 - Pandemic confirmed Phase 2 - Outbreaks in multiple geographic areas Phase 3 - End of first wave Phase 4 - Second or later waves Phase 5 - Post-Pandemic / Recovery

  34. International Pandemic Preparedness Development of pandemic plans Approximately 30 countries worldwide have a plan Use of the WHO Pandemic Phases improves communication and consistency Requires national coordination and agreement on goals of pandemic preparedness and response National surveillance for influenza-like illness and influenza viruses Vaccine strategies Development of Stockpiles / Antiviral strategy

  35. Canadian Planning Federal • CEPR - Center for Emergency Preparedness & Response - stockpiling of antiviral drugs - emergency supplies (tents/blankets/etc) • Division of Immunization & Respiratory Infection • Canadian Pandemic Planning Committee - pandemic influenza contract (ID Biomedical) - pandemic vaccine testing protocol Provincial &Territorial Planning Committees

  36. Thank you for you attention

  37. Lessons Learned: Coordination and Operations Clear command structure required Provinces without well developed pandemic plans had to create structures immediately to deal with health emergency Dedicated team leadership is essential Need to strengthen human resource planning and surge capacity in emergency plans Psycho-social support: post traumatic stress

  38. Lessons Learned: Disease Control Quarantine and isolation measures were generally acceptable to the public Cancellation of public gatherings will happen regardless of public health recommendations Multiple partners need to be involved in the implementation of public health measures Education and information dissemination media, NGOs, professional societies, businesses, schools… Blood and border issues will arise quickly

  39. Lessons Learned: Surveillance Lack of integrated mechanisms and processes for surveillance Strengthen interface between hospital and public health Epidemiological, clinical and laboratory data linkage Establish case definitions with rationale Consistent use of definitions nationally AND strive for international consistency Pre-establish minimum dataset and data sharing agreements for emerging infectious diseases Establish mechanism for alerting public health and health care providers in real time

  40. Lessons Learned: Outbreak Investigation Enhance epidemiological capacity at all levels multi-disciplinary outbreak investigation teams Improve ability to mobilize resources across jurisdictions Clarify or establish roles and responsibilities and collaboration mechanisms for a multi-jurisdictional response Increase training programs, including short courses that can be rapidly implemented

  41. Lessons Learned: Communication Pre-established national networks worked; need to strengthen international networks Establish communication processes that permit optimal use of all participants time Human resources needed to translate science (particularly epidemiology) into public information Potential for case counts to become politicized Perception IS reality

  42. Lessons Learned: Infection Control in Acute Care Settings Lack of trained infection control personnel Varying capacity for surveillance and need to coordinate with public health Negative impact of intensive SARS infection control measures Health care worker well-being Increase in other nosocomial infections e.g. MRSA, VRE Missed or not reported tuberculosis cases Ongoing training needed e.g. how to put on / remove personal protective equipment

  43. Lessons Learned: Health Services Pandemic influenza guidelines useful Resource management Managing hospital triaging and transfers Dedicated SARS units Lack of supplies Staff exhaustion Security requirements Non-traditional sites / workers Sites administered through acute care setting City buses as screening units outside hospitals Lack of volunteers, no medical/nursing students

More Related