WGHA Discovery Series: David Heymann


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Washington Global Health Alliance Discovery Series

David Heymann, MD
June 19, 2008
'Challenges and Controversies in Polio Eradication'

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  • WGHA Discovery Series: David Heymann

    1. 1. Polio Eradication: Challenges and Controversies
    2. 2. Smallpox: Variola Major 20% - 40% case fatality 100% permanent facial scarring 2.7 million deaths, 1967
    3. 3. Challenge, 1967: Smallpox endemic in 31 countries or territories Endemic Importation Transmission interrupted
    4. 4. Smallpox eradication: scientific basis for 1967 decision to eradicate <ul><li>No reservoir in nature </li></ul><ul><li>Vaccine provides protection against infection, </li></ul><ul><li>easy to administer, inexpensive and heat stable </li></ul><ul><li>Each infection full clinical expression/no </li></ul><ul><li>asymptomatic infection </li></ul><ul><li>Transmission mainly face to face by droplet, not </li></ul><ul><ul><li>through environmental contamination </li></ul></ul><ul><li>Feasibility proven in industrialized countries </li></ul>
    5. 5. Smallpox eradication: field strategies, 1967–1978 <ul><li>Search: </li></ul><ul><ul><li>house to house </li></ul></ul><ul><ul><li>market </li></ul></ul><ul><ul><li>public gatherings/festivals </li></ul></ul><ul><li>Containment: </li></ul><ul><ul><li>isolate patient </li></ul></ul><ul><ul><li>vaccinate household members/contacts </li></ul></ul><ul><ul><li>vaccinate 30 neighbouring households </li></ul></ul><ul><ul><li>+ vaccinate rest of village/ neighbouring villages </li></ul></ul>
    6. 6. Intensified search: smallpox eradication, 1967–1978 WHO Smallpox Recognition Card
    7. 7. Simplified containment: smallpox eradication, 1967–1978 Multipuncture vaccination by bifurcated needle
    8. 8. Smallpox eradication: global partnership to detect/contain every case Ethiopia Somalia
    9. 9. Smallpox, the last endemic infection, Somalia, October 1977
    10. 10. Smallpox, the last human infection, Birmingham, Uninted Kingdom, November 1978
    11. 11. Smallpox Eradication: Certified 1980
    12. 12. Smallpox eradication: savings in cost of vaccination and death/disability averted <ul><li>1967–1979 </li></ul><ul><ul><li>cost of eradication: US$ 300 million </li></ul></ul><ul><li>1967 </li></ul><ul><ul><li>cost in lives approximately 2.7 million </li></ul></ul><ul><ul><li>cost to the world US$ 1.4 billion </li></ul></ul><ul><ul><li>cost for vaccination in USA US$ 92.8 million </li></ul></ul><ul><ul><ul><li>9 deaths </li></ul></ul></ul><ul><ul><ul><li>4 permanent disabilities </li></ul></ul></ul><ul><li>1983 </li></ul><ul><ul><li>USA saves equivalent of its investment in WHO smallpox eradication programme every 26 days </li></ul></ul>
    13. 13. Smallpox virus: officially remains in 2 WHO Collaborating Centres CDC (ATLANTA) KOLTSOVO (SIBERIA)
    14. 14. Reports of virus outside WHO repositories 2000: real or perceived threat? <ul><li>Updated WHO guidance </li></ul><ul><li>Intensified research on new vaccines, antivirals and diagnostics in US and Russia </li></ul><ul><li>Industry scaled up smallpox vaccine production </li></ul><ul><li>Industrialized countries stockpiled smallpox vaccine/vaccinia immune globulin </li></ul><ul><li>No effective antiviral or rapid diagnonstic </li></ul>
    15. 15. <ul><li>No reservoir in nature </li></ul><ul><li>Vaccine provides full protection, easy to administer from birth </li></ul><ul><li>Transmission faecal/oral contamination in environment </li></ul><ul><li>Feasibility proven in industrialized countries </li></ul><ul><li>Up to 600 – 1000 asymptomatic infections for each child with acute flaccid paralysis (3 virus types) </li></ul>Polio eradication: scientific basis for 1988 resolution to eradicate
    16. 16. World Health Assembly Resolution: polio eradication by year 2000 <ul><ul><li>1. DECLARES the commitment of WHO to the global eradication of poliomyelitis by the year 2000; </li></ul></ul><ul><ul><li>2. EMPHASIZES that eradication efforts should be pursued in ways which strengthen the development of the Expanded Programme on Immunization as a whole, fostering its contribution, in turn, to the development of the health infrastructure and of primary health care; </li></ul></ul>FORTY-FIRST WORLD HEALTH ASSEMBLY GENEVA, 2-13 MAY WHA41.28 Global eradication of poliomyelitis by the year 2000
    17. 17. Strategy 1: routine childhood immunization Routine childhood immunization in national immunization programmes High level advocacy and political engagement
    18. 18. Reality: weak national immunization programmes Routine Polio Coverage, by Region
    19. 19. Strategy 2: national immunization campaigns 2002: 100 countries
    20. 20. Reality: inability to sustain campaigns when external resources decrease 2003: <20 countries, fewer campaigns
    21. 21. Specialised Reference Laboratory Regional Reference Laboratory National/ Sub-national Laboratory Strategy 3: clinical/laboratory surveillance of acute flaccid paralysis
    22. 22. Virus linked to common ancestor, West and Central Africa, 2004
    23. 23. Polio eradication progress 1988 - 2003 <ul><li>1988 350 000 children </li></ul><ul><li>125 countries </li></ul><ul><li>Inequitable access to polio vaccine </li></ul>Type 2 wild poliovirus last transmitted in 1999 2003 784 children 6 countries Equitable access to polio vaccine
    24. 24. Challenge: suspension of polio immunization, Nigeria, August 2003 Polio Vaccines - Western Countries Exploit Developing Ones Says Kano State Governor Shekarau BYLINE: Daily Trust BODY: The Kano State governor, Malam Ibrahim Shekarau, has asserted that the people's objections to polio vaccines has confirmed the exploitative actions of western nations towards developing countries.
    25. 25. 6 polio endemic countries 18 countries with imported virus Wild virus type 1 Wild virus type 3 International spread of polio from Nigeria, 2003-2005
    26. 26. Increased political commitment, West and Central Africa Nigerian President Obasanjo & African Union President Konare launch Kano campaign, 2004 Rotary/UN mediation mission, Côte d'Ivoire, February 2005
    27. 27. Coordinated Africa-wide vaccination campaigns 2004 Jan – May 2005 June 2005 5 Rounds of synchronized National Immunization Days, Oct 2004 - May 2005
    28. 28. Political advocacy for polio eradication <ul><li>10 th Islamic Summit Polio Resolution, Malaysia, 2003 </li></ul><ul><li>Islamic Conference of Foreign Ministers Meeting Polio Resolutions (Turkey 2004, Pakistan 2007) </li></ul><ul><li>3 rd Extraordinary Islamic Summit, Mecca, 2005 </li></ul>'Noting OIC countries now suffer the greatest burden of polio, call for political & financial support of OIC member states to finish eradication'
    29. 29. Religious advocacy for polio <ul><li>Rulings & Fatwas on the need and safety of polio vaccines: </li></ul><ul><ul><li>the Grand Imam of El Azhar Al Sharif, </li></ul></ul><ul><ul><li>International Union for Moslem Scholars </li></ul></ul><ul><ul><li>The Mufti of Egypt </li></ul></ul><ul><ul><li>Mawlana Fazul Rahman </li></ul></ul><ul><ul><li>The Islamic Fiqh Academy - Jeddah </li></ul></ul><ul><ul><li>Dr Y. Al Qaradawi, European Council for Fatwa and Research . </li></ul></ul><ul><ul><li>Visit of Imam Cheik Cisse to northern Nigeria. </li></ul></ul>
    30. 30. Weekly epidemiological record 6 AUGUST, 2004 <ul><li>The international spread of wild poliovirus </li></ul><ul><li>On 30 June 2004, WHO highlighted an increasing </li></ul><ul><li>risk of international spread of wild poliovirus1 </li></ul><ul><li>and updated its advice for travellers on steps </li></ul><ul><li>they could take to increase their personal protection </li></ul><ul><li>against wild poliovirus. Subsequently, on 16 </li></ul><ul><li>July 2004, an* Ad Hoc Expert Consultative Group </li></ul><ul><li>on Polio and Public Health was convened by the </li></ul><ul><li>Director-General of WHO to discuss potential </li></ul><ul><li>measures to prevent or limit the international </li></ul><ul><li>spread of wild poliovirus. </li></ul>
    31. 31. Standing recommendation, International Health Regulations: August 2004
    32. 32. * data as on 10th September 2005 Challenge: polio a disease of vaccinated children in high population density countries 7 - 9 doses 27% 4 - 6 doses 27% >=10 doses 46% Vaccination status, children with polio, Uttar Pradesh, India 2005
    33. 33. Limited protection from trivalent oral polio vaccine: virus competition Percent John TJ, Devararjan LV, Balasubramanyan A. Immunization in India with trivalent and monovalent oral poliovirus vaccines of enhanced potency. Bull WHO 1976;54:115-7.
    34. 34. <ul><li>Objectives: </li></ul><ul><li>Decrease in competition among three virus types </li></ul><ul><li>Marked increase in level of protection with 1 st dose </li></ul>Improvement in protection: monovalent oral polio vaccine Protection against type 1 polio after one birth dose of mOPV1 vs. one dose tOPV 34% 61% 0 25 50 75 100 tOPV mOPV1
    35. 35. Monovalent oral polio vaccine types 1 and 3 (mOPV1 and mOPV3) Monovalent oral polio vaccine: greater herd immunity for fewer doses
    36. 36. Effective use of mOPV1, India, 2005 Type1 polio 2005 data as of 25 Sept 2005 mOPV mOPV mOPV tOPV tOPV tOPV mOPV *13 high risk districts, West Uttar Pradesh 0 2 4 6 8 10 12 14 16 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2004 2005
    37. 37. Wild poliovirus type 1 Sabin poliovirus type 1 2004 2005 Poliovirus isolated from sewage, Egypt, August 2004 – August 2005 year
    38. 38. Protective efficacy by dose, tOPV and OPV by country, 2005 - 2007
    39. 39. Direct protection against type 1 polio in children <5 years Impact on immunity to type 1 polio India and Nigeria 2005 2006 2007 2005 2006 2007
    40. 40. Type 1 Polio paralysis worldwide, 4 June 2008 Endemic countries Wild virus type 1 New importations (2008) Persistent imports (2006-7)
    41. 41. Type 3 Polio Cases at 4 June 2008 Endemic countries Wild virus type 3 New importations (2008) Persistent imports (2006-7)
    42. 42. Risks to polio eradication: June 2008 Active conflict Autonomous areas Lack of political & societal engagement Very efficient transmission
    43. 43. Polio outbreak, China, 2004 Polio outbreak 2 cases
    44. 44. Dilemma: circulating vaccine-derived polioviruses (cVDPVs) Philippines 2001 3 cases Madagascar 2002 4 cases China 2004 2 cases Indonesia 2005 46 cases Nigeria 2006-7 89 cases Hispaniola 2000 22 cases
    45. 45. iVDPV and long-term excretion known to WHO <ul><li>28 cases identified during 40 years use of OPV </li></ul><ul><li>type 1, type 2, type 3 </li></ul><ul><li>Europe, USA , Japan , Argentina , Taiwan , Iran, Zimbabwe </li></ul><ul><li>3 known to be presently excreting </li></ul>Immunodeficiencies linked to persistent poliovirus infections cvid agamma ab deficient scid under investign
    46. 46. Vaccine derived polio viruses: definitions <ul><li>iVDPV is a virus with >1% drift from parent OPV strains by full VP1 sequence, isolated from a patient either </li></ul><ul><ul><li>with evidence of immune deficiency, or </li></ul></ul><ul><ul><li>with multiple isolates over several months </li></ul></ul><ul><li>cVDPV is a virus with >1% difference from parent OPV strains by full VP1 sequence homology found by AFP surveillance </li></ul><ul><ul><li>consistent with an extensive period of virus excretion or transmission </li></ul></ul><ul><ul><li>generally in a areas with low OPV coverage rates </li></ul></ul>
    47. 47. Vaccine-associated risks to polio eradication from OPV iVDPV 28 identified <1 decreases ( since 1963) cVDPV 1* per year 10 increases VAPP 2-4/million 1 st dose 250-500 stable Frequency Annual Evolution Risk to date burden over time *based on current understanding After interruption of wild poliovirus, continued use of OPV will compromise the goal of a polio-free world. Expert Consultation on Vaccine-derived Polioviruses (VDPVs), Sept 2003, Geneva
    48. 48. OPV cessation after certification of polio eradication <ul><ul><li>Risk of VDPV </li></ul></ul><ul><ul><li>Years after last wild poliovirus </li></ul></ul>0 1 2 4 5 3 Routine immunization and campaigns, AFP surveillance Vaccine stockpile and response mechanism, AFP surveillance (IHR) <ul><ul><li> cVDPV emergence </li></ul></ul>Potential Target Date for OPV Cessation
    49. 49. VAPP 2-4/million birth cohort 250-500 stable iVDPV 19 identified <1 decreases ( since 1963) cVDPV 1* per year 10 increases IPV sites 1 accident (1990s) <1 decreases lab accident 1 investigation NK decreases deliberate 0 NK unknown Frequency Annual Evolution Risk to date burden over time Vaccine-associated and other risks to polio eradicatyion
    50. 50. Laboratory specimens of poliovirus after eradication <ul><li>Polio virus widespread in laboratories throughout the world: </li></ul><ul><ul><li>Known wild poliovirus </li></ul></ul><ul><ul><li>Known Sabin poliovirus </li></ul></ul><ul><ul><li>Potential infectious materials (wild and Sabin poliovirus) </li></ul></ul><ul><ul><li>Wild and Sabin poliovirus used in production of inactivated polio vaccine (IPV) </li></ul></ul>
    51. 51. Worldwide containment, wild poliovirus: status 2007 Polio endemic Survey not yet started Conducting survey Reporting completion of survey and inventory of laboratories with wild poliovirus materials
    52. 52. 2008-9 Funding Gap: US$ 525m of $1.3b budget ‘ Other’ includes: the Governments of Angola, Austria, Australia, Belgium, Czech Republic, Finland, Hungary, Iceland, Ireland, Italy, Liechtenstein, Luxembourg, Malaysia, Monaco, Namibia, New Zealand, Nigeria, Oman, Pakistan, Portugal, Qatar, Republic of Korea, Russian Federation, Saudi Arabia, Singapore, Spain, Switzerland, Turkey, the United Arab Emirates; African Development Bank; AG Fund; American Red Cross; De Beers, Inter-American Development Bank, Central Emergency Response Fund (CERF), International Federation of Red Cross and Red Crescent Societies, Oil for Food Programme, OPEC Fund, Sanofi Pasteur; Saudi Arabian Red Crescent Society, Smith Kline Biologicals, UNICEF National Committees, UNICEF Regular and Other Resources, United Arab Emirates Red Crescent Society, WHO Regular Budget and Wyeth. Domestic Resources 14% Non-G8 OECD/ Other 8% Multilaterals 15% Private Sector 15% Cost of eradication (1988-2009) US$ 6 Billion G8 48%
    53. 53. Smallpox Eradication: Certified 1980, cost US $300 million
    54. 54. Persons living with HIV infection, 2006: >40 million 3 million deaths during 2003 20 million deaths since 1981 Smallpox vaccine cannot safely be used in HIV-infected persons
    55. 55. THE CHALLENGE <ul><li>Complete polio eradication while the window of opportunity remains open </li></ul>
    56. 56. Spread of polio from India and Nigeria: 27 previously polio-free countries in 2003-7 The Risk
    57. 57. The public good
    58. 58. Surveillance for acute flaccid paralysis <ul><li>Accurately identifies children with acute flaccid paralysis </li></ul><ul><li>Investigates each child, collects and transports specimens to laboratory </li></ul><ul><li>Analyzes specimens, determines where polio is, and where polio is not </li></ul><ul><li>Ensures supervised vaccination response, &quot;pulling&quot; vaccines from manufacturers to national stores and children providing over 90% access </li></ul><ul><li>Maintains vehicles, cell and satellite phones, computers, offices and office equipment/supplies, laboratory equipment and supplies </li></ul>
    59. 59. Polio staff by region, 2008 Region International Staff National Staff Total FT ST* FT ST* SSA NPO APW AFRO 31 120 5 572 355 14 0 1097 AMRO 1 0 0 3 0 2 0 6 EMRO 13 83** 7 19 439 0 457 935 EURO 2 1.5 2 2 0 2 0 9.5 SEARO 13 12 5 11 1151 0 0 1192 WPRO 2 0 0 0 1 0 0 3 HQ 23 12 11.5 4.5 0 0 0 51 TOTAL 85 145.5 30.5 611.5 1946 18 457 3293.5
    60. 60. Micro-planning and mapping for Immunization campaigns in rural Pakistan
    61. 61. Current Level: WHO Pandemic Influenza Alert <ul><li>Pandemic period </li></ul><ul><li>Pandemic alert period </li></ul><ul><li>Inter-pandemic period </li></ul><ul><li>Phase 6 </li></ul><ul><li>Phase 5 </li></ul><ul><li>Phase 4 </li></ul><ul><li>Phase 3 </li></ul><ul><li>Phase 2 </li></ul><ul><li>Phase 1 </li></ul><ul><li>Increased and sustained transmission in general population. </li></ul><ul><li>Larger cluster(s) but human-to-human spread still localized </li></ul><ul><li>Small cluster(s) with limited human-to-human transmission but spread is highly localized. </li></ul><ul><li>Human infection(s) with a new virus, but no (or very infrequent) human-to-human spread. </li></ul><ul><li>No human infections, but a circulating animal influenza virus poses a risk to humans. </li></ul><ul><li>No new influenza virus detected in humans. If a new influenza virus presents in animals, the risk of human infection is considered to be low. </li></ul>
    62. 62. Rapid containment response, early phase 4 pandemic alert <ul><li>Interrupt transmission from human to human/prevent further spread: ring containment </li></ul><ul><ul><li>Early detection and response </li></ul></ul><ul><ul><li>Prevention of human to human transmission using anti-viral drugs </li></ul></ul><ul><ul><li>Prevention of human to human transmission by vaccination using H5N1 vaccine </li></ul></ul>
    63. 63. Vaccines and antiviral drugs for H5N1 and pandemic influenza <ul><li>Antiviral drugs </li></ul><ul><li>H5N1 and Pandemic vaccine </li></ul><ul><li>Social mobilization </li></ul>