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Preparing for the Next Influenza Pandemic

Preparing for the Next Influenza Pandemic. Susan E. Tamblyn, MD, DPH, FRCPC Medical Officer of Health Perth District Health Unit. University of Toronto. November 15, 2002. contact: tamblyn@pdhu.on.ca. Learning Objectives.

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Preparing for the Next Influenza Pandemic

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  1. Preparing for the Next Influenza Pandemic Susan E. Tamblyn, MD, DPH, FRCPC Medical Officer of Health Perth District Health Unit University of Toronto November 15, 2002 contact: tamblyn@pdhu.on.ca

  2. Learning Objectives At the end of this educational session, participants should be able to: 1. describe influenza pandemics and their potential impact 2. discuss the role played by international, federal, provincial and local agencies in planning for and responding to an influenza pandemic 3. discuss current status of strategies for surveillance, vaccines and antivirals, health services planning, emergency response, and communications 4. create an effective local pandemic plan

  3. Why Focus on Pandemic Planning? • next influenza pandemic could to be associated with high mortality, morbidity and societal disruption worldwide • emergency will be complex, rapidly evolving and provoke public alarm • too late at its onset to take many steps to lessen its impact • planning will enhance capacity to respond to other public health emergencies (including bioterrorism) and improve response to annual flu epidemics

  4. Influenza 101 • • of the 3 influenza types (A, B and C), only influenza A is associated with pandemics • • influenza A subtypes are classified by their surface • proteins: haemagglutinin (H) and neuraminidase (N) • • 15H and 9N subtypes known • humans affected mainly by H subtypes 1-3 • • aquatic birds are the reservoir for all subtypes

  5. Where Do Influenza Epidemics Originate? • evidence suggests most epidemics emerge from China • close mingling of ducks, pigs, humans allows reassortment of viruses • minor changes called “drift”; if big enough result in new epidemic • at unpredictable intervals, major changes called “shift” occur that result in a pandemic (3-4 per century)

  6. Source: Nature Medicine 1998; 4:1122-3.

  7. Source: Nature Medicine 1998; 4:1122-3.

  8. Setting for a Pandemic •emergence of an influenza A subtype with a new / different haemagglutinin • high proportion of susceptible people in the population • high person-to-person transmission of the new virus, with accompanying human disease

  9. History of Influenza Pandemics Year Influenza A Strain 1847 ? 1889 - 1890 H2N2 1899 - 1900 H3N2 1918 - 1919 H1N1 Spanish flu 1957 H2N2 Asian flu 1968 H3N2 Hong Kong flu (1977 H1N1)

  10. Observations from Previous Pandemics • 1-6 months warning from first global alert to local outbreaks • 1st wave often out-of-season, lasts 6-8 weeks (peak at 3-4 weeks) • 2nd wave 3-9 months later; may be more severe • 3rd wave may also occur

  11. Pandemic Epidemiology II • many hospitalizations and deaths will be in young, previously healthy people • percentage of deaths < age 65: • 1918 99% • 1957 36% • 1968 48% • pneumonia deaths predominated in 1918 • (both primary viral and secondary bacterial) • in 1957 & 1968, cardiovascular and other complications accounted for about half of deaths

  12. Pandemic Mortality No. of deaths Death rate Worldwide Canada per 100,000 pop. 1918-19 40-50 m 50-60,000 218 1957 > 1 m 7,000 22 1968 3,000 14

  13. Pandemic Impact in Ontario • up to 8 million people will be infected (up to 75%) • 1.6 - 4 million will be clinically ill (up to 38%) • 0.7 - 1.8 million will require outpatient care (up to 17%) • 12 - 32,000 will require hospitalization (up to 0.3%) • 3,000 - 12,000 deaths (up to 0.1%) (Extrapolated from CDC estimates)

  14. 1976 “Swine Flu” Lessons (H1N1) • • decision-making process • mass vaccination program • unexpected vaccine adverse events (GBS) • need for domestic vaccine security • led to first Canadian pandemic plan

  15. 1997 “Hong Kong Incident” Lessons (H5N1) • avian source – significant lab biosafety issues; control issues • difficulties in vaccine production • communications were over-riding concern • wake-up call worldwide for pandemic planning

  16. Discussion & Questions

  17. WHO’s Role in Influenza • 50+ years of surveillance activities: • - 4 WHO collaborating centres • - 112 national influenza labs • - collaborating centre for animal influenza • viruses • determine composition for annual vaccines • Pandemic Preparedness Plan (1999) • WHO Global Strategy (2002)

  18. Components of the Global Agenda A. Strengthen epidemiological & virological surveillance B. Increase knowledge on health & economic burden of disease C. Increase influenza vaccine use D. Accelerate national and international action on pandemic preparedness

  19. Accelerate national and international action on pandemic preparedness • 1. increase awareness of the need for pandemic planning • 2. accelerate development and implementation of national pandemic plans • 3. enhance use of vaccine and antivirals in the interpandemic period • 4. develop strategies for use of vaccines and antivirals and securing adequate supplies in a pandemic • 5. advocate research on pandemic viruses, vaccines, antivirals and other control measures

  20. WHO’s Role in a Pandemic • task force to assist in viral and epidemiologic studies • heightened surveillance through WHO network • official declaration of the pandemic • preparation of seed strains and reagents for vaccine development • advice on response, including use of vaccines and antivirals

  21. WHO Response Phases Phase 0 - interpandemic activities Phase 0, Preparedness Level l - new strain in human case Phase 0, Preparedness Level 2 - human infection confirmed (2 or more) Phase 0, Preparedness Level 3 - human transmission confirmed Phase 1 - onset of pandemic Phase 2 - regional & multi-regional epidemics Phase 3 - end of 1st pandemic wave Phase 4 - 2nd or later waves Phase 5 - end of the pandemic

  22. Some Global Realities • pandemic could emerge in China where surveillance and info sharing is still weak • rapid dissemination through air travel • developing countries will be as hard hit as elsewhere – maybe worse • no antivirals unless stockpiled • vaccines will not be available for 6 or more months

  23. Global Realities II • countries with vaccine manufacturers may nationalize supplies • only 8 countries have domestic vaccine manufacturer • current production serves < 5% of world population • about 30 countries have pandemic plans

  24. Vaccine & Antiviral Strategies • Key points from recent WHO consultation: • expect shortages of both vaccines and antivirals • wise use follows goals and priorities chosen by a country • probably need 2 doses of vaccine for a naïve population • monovalent vaccine to be used • options to improve immunity include whole cell vaccines and use of adjuvants

  25. Vaccine & Antiviral Strategies II • antiviral use is totally dependent on stockpiles • options are prophylaxis (PEP or during full pandemic wave) and/or treatment • need to avoid amantadine / rimantadine for treatment • issues of sharing with “have not” countries

  26. Discussion & Questions

  27. Pandemic Planning in Canada • ongoing activity for 20 years • major revisions under way since Hong Kong incident • in 1997 • federal/provincial planning meetings held in 1999 and 2000 provincial / local planning • F/P/T agreement led to establishment of PIC (Pandemic Influenza Committee) and funding of a vaccine strategy • challenge now to integrate with bioterrorism planning

  28. Canadian Pandemic Influenza Plan • Plan will have three sections: • preparedness section – developed by CIDPC • now out for review • response – being developed by CIDPC and CEPR • recovery – not yet developed

  29. Framework for Planning & Response • Key sections: • Surveillance • Antivirals • Health Services Emergency Planning • Emergency Planning & Response • Communications • Plan describes components and key planning activities (checklists) and has annexes and guidelines.

  30. Canadian Pandemic Response Goal • to reduce influenza morbidity and mortality and minimize societal disruption among Canadians by providing access to appropriate prevention, care and treatment

  31. Surveillance • objectives are to detect emergence, spread and impact of novel strains in Canada • may include special studies at borders and major points of arrival • early need to identify population susceptibility to new strain • both virologic and activity surveillance, including outbreak investigation and real-time mortality tracking

  32. Surveillance – Local Responsibilities • advance planning for activity monitoring • eg sentinel physicians, school or workplace • absenteeism, emergency room visits • virologic surveillance will be directed by the province – to include resistance monitoring • need rapid flow and analysis of data • local epidemiologic picture triggers other response eg antiviral prophylaxis, hospital response

  33. Vaccines • Canada has a pandemic contract with Shire to develop capacity to produce enough vaccine for whole population (includes continuous availability of fertilized eggs) • expedited approval mechanisms and clinical trial protocols are under development • need to monitor uptake, adverse events and vaccine effectiveness • national priorities for vaccine use

  34. Priority Groups for Vaccination • Health care workers • Essential service workers • Persons at high risk of severe or fatal outcomes • long term care facilities • NACI high risk • seniors • children < 2 • pregnant women • 4. Healthy adults • 5. Children 2-18 years

  35. Vaccines – Local Responsibilities • plan to vaccinate whole population with 2 doses a month apart • might or might not be able to use family doctors as vaccinators (not during wave of illness) • develop generic mass vaccination plan, using universal flu experience and Waterloo and Alberta reports • plan tracking of uptake, adverse events

  36. Antivirals • Canada’s antiviral strategy and stockpile is not yet approved • antivirals will likely be our only intervention for the first wave • antiviral distribution will be controlled, probably through public health • need to monitor uptake, adverse events, resistance and effectiveness

  37. Priority Groups for Antivirals • treatment of persons hospitalized for flu • treatment of high risk persons in community • prophylaxis of health care workers • outbreaks in LTCF • prophylaxis of essential service workers • prophylaxis of other hospitalized patients • prophylaxis of high risk persons in community • treatment of ill persons (not high risk)

  38. Assumptions • prophylaxis is for six weeks – • triggered by arrival of flu in local area • treatment is for five days • and only for persons ill < 48 hours • amantadine is used only for prophylaxis (to prevent development of resistance) • neuraminidase inhibitors are used for treatment

  39. Antivirals – Local Planning • develop mass distribution plan for public health controlled drug (can be generic – anthrax etc) • potential scenarios: • - hospitals dispense for patient and health care worker prophylaxis (pharmacy committee control) • - Health Unit or community pharmacy clinics for ESW’s and other HCW’s • - selected pharmacies for Rx courses

  40. Health Services Emergency Planning • problems – no surge capacity, shortage of personnel at time of high demand and increased risk of infection • extensive clinical guidelines have been developed: • clinical management • triage • resource management • mass casualties • non-traditional sites and workers • infection control

  41. Health Services – Local Planning • ideal is integrated response involving doctors, clinics, hospitals and CCAC • establish plans for community clinics / triage sites • establish hospital expansion plans / alternate sites • clarify communication between health services and public health

  42. Community Control Measures • general advice for public • emphasis on personal and hand hygiene • community mask use felt ineffective • effectiveness of closure of public places, including schools needs more study • (modeling ?)

  43. Communications • federal communications plan still under development • expect templates, fact sheets, key messages, guidelines, etc • secure web site will be used • essential to harmonize with all levels of government – consistent messaging

  44. Communications – Local Planning • develop public health emergency communications plan (not just for pandemics) • identify stakeholders and communication strategies to reach them • dispelling rumors and myths

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