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Virology, Poliomyelitis

Publié dans : Santé & Médecine


  1. 1. Highlights of the Global Polio Eradication Initiative Strategic Plan 2009-2013 Virology Discipline Meeting - 24 February 2009 Dr Preneshni R Naicker
  2. 2. Goal of the Global Polio Eradication Initiative: To ensure that no child will ever again be paralysed by either a wild or vaccine-derived poliovirus
  3. 3. Objective 1: Interrupt wild poliovirus transmission
  4. 4. Areas with Active Polio Transmission 1988 > 125 endemic countries 2006* 4 endemic countries 8 reinfected countries
  5. 5. Situation analysis <ul><li>Indigenous poliovirus eradicated from all but 4 countries worldwide </li></ul><ul><li>India, Nigeria, Pakistan, Afghanistan, indigenous type 1 and 3 wild poliovirus transmission is continuing </li></ul><ul><li>Type 2 wild poliovirus has been eradicated globally since 1999 </li></ul>
  6. 6. Key challenges <ul><li>1) Sub-optimal OPV delivery </li></ul><ul><li>2) Sub-optimal OPV efficacy </li></ul><ul><li>3) Prolonged outbreaks (persistent transmission for >12 months) due to suboptimal outbreak response </li></ul><ul><li>4) Continued international spread of poliovirus from areas of indigenous (eg Nigeria, India) and imported poliovirus transmission (eg Angola, Chad, parts of the Horn of Africa) </li></ul>
  7. 7. Strategic approach <ul><li>In all polio-infected areas: </li></ul><ul><li>Implement an aggressive SIA strategy </li></ul><ul><li>prioritize eradication of type 1 poliovirus (higher paralytic attack rate and propensity for geographic spread) </li></ul><ul><li>Optimize the OPV campaign </li></ul><ul><li>In areas of prolonged outbreaks </li></ul><ul><li>International outbreak response guidelines </li></ul><ul><li>To address international spread </li></ul><ul><li>Maintain/increase routine immunization </li></ul><ul><li>Ensure immediate notification of newly-infected areas </li></ul>
  8. 9. Objective 2: Ensure sustainable surveillance for polioviruses
  9. 10. Situation analysis <ul><li>Surveillance for acute flaccid paralysis (AFP) cases: </li></ul><ul><li>In endemic regions </li></ul><ul><li>59 of 66 countries are achieving certification standard surveillance </li></ul><ul><li>In polio-free regions </li></ul><ul><li>16 of 80 countries are achieving certification standard surveillance </li></ul><ul><li>Global Polio Laboratory Network (GPLN): </li></ul><ul><li>141 of 145 laboratories are fully accredited by WHO </li></ul><ul><li>In 2008, new Real-time PCR assays to improve screening for vaccine-derived polioviruses (VDPVs) were evaluated </li></ul><ul><li>Environmental surveillance : </li></ul><ul><li>Systematic environmental sampling (in Egypt and Mumbai, India) </li></ul><ul><li>Environmental surveillance elsewhere (especially in polio-free regions as part of broader enterovirus surveillance systems) </li></ul>
  10. 11. Key challenges <ul><li>Persistence of surveillance gaps </li></ul><ul><li>Revitalizing AFP surveillance to achieve certification-standard in polio free areas </li></ul><ul><li>Enhancing the speed of detection of wild polioviruses and VDPVs globally </li></ul><ul><li>Coordinating a system for environmental surveillance efforts globally </li></ul>
  11. 12. Achieve certification-standard surveillance, down to subnational level Achieve certification-standard surveillance globally, at national level Initiate global environmental surveillance strategy Introduce new laboratory procedures globally Achieve enhanced surveillance standards (AFP rate >2) at the subnational level in all high risk, re-infected and endemic areas Through end-2013, achieve certification-standard surveillance, down to subnational level End-2013 End-2012 End-2011 End-2010 End-2009 5-year target
  12. 13. Objective 3: Achieve certification & containment of wild polioviruses
  13. 14. <ul><li>Certification-standard surveillance </li></ul><ul><li>A minimum AFP detection rate of 1 case per 100,000 children <15 yrs </li></ul><ul><li>At least 80% of AFP cases have adequate stool collection </li></ul><ul><li>Stool adequacy  2 x 5-10g stool specimens taken 24-48 hrs apart within 14 days of onset of paralysis </li></ul>
  14. 15. <ul><li>Certification of Global Polio eradication </li></ul><ul><li>Before a WHO region can be certified polio-free: </li></ul><ul><li> at least 3 years of no wild polio virus cases </li></ul><ul><li> under conditions of certification-standard surveillance </li></ul><ul><li> demonstrate capacity to detect, report & respond to ‘imported’ polio cases </li></ul>
  15. 16. Situation analysis <ul><li>Three Regions are certified polio-free (AMR, EUR, WPR). </li></ul><ul><li>Regional Certification Commissions (RCCs) are functioning in all three remaining endemic Regions, with National Certification Committees </li></ul><ul><li>A framework for long-term containment of all polioviruses has been established </li></ul>
  16. 17. <ul><li>Containment of wild polio virus stocks </li></ul><ul><li>Purpose: To minimize the risk of an accidental or intentional reintroduction of wild poliovirus into the community from a laboratory or vaccine production site post-eradication </li></ul><ul><li>Aim: to locate laboratories worldwide that store wild poliovirus and potentially infectious materials, and ensure that those materials are handled under appropriate biosafety conditions. </li></ul>
  17. 18. Key challenges <ul><li>Establishing international consensus on long-term containment requirements for all polioviruses </li></ul><ul><li>Strategic approach </li></ul><ul><li>Establish an area-specific process for certifying eradication in each conflict-affected area </li></ul><ul><li>Finalize and implement the long-term containment activities </li></ul>
  18. 19. Objective 4: Prepare for VAPP & VDPV elimination & the post-OPV era
  19. 20. Situation analysis <ul><li>The VAPP burden is 250-500 cases/yr </li></ul><ul><li>Since 2000, at least 10 cVDPV outbreaks in 10 countries </li></ul><ul><li>Of 33 recorded individuals with iVDPVs, 5 have excreted for >5 years (chronic excretors) </li></ul><ul><li>?date for the eventual cessation of the use of OPV in routine immunization programmes </li></ul>
  20. 21. Key challenges <ul><li>Fully characterising VDPV risks in low- and middle-income settings </li></ul><ul><li>Coordinating OPV cessation internationally as soon as possible after certification of wild poliovirus eradication. </li></ul><ul><li>Developing affordable options for IPV use in low- and middle-income countries </li></ul><ul><li>Establishing a process for verification of VAPP/VDPV elimination. </li></ul>
  21. 22. Strategic approach <ul><li>Expand new laboratory diagnostic procedures to enhance sensitivity to detect VDPVs </li></ul><ul><li>Implement studies to better quantify and characterize iVDPV risks/implications </li></ul><ul><li>Develop antiviral drugs to treat chronic iVDPVs </li></ul><ul><li>Establish affordable IPV options </li></ul><ul><li>Establish WHA Resolutions on the eventual coordination of OPV cessation, long-term containment of all polioviruses and use of mOPV in response to cVDPVs following OPV cessation (including use of international stockpile of mOPV) </li></ul><ul><li>Update risk assessment on potential for intentional use of polioviruses in the post-eradication era. </li></ul>
  22. 23. Objective 5: Plan for Re-structuring of the Global Polio Eradication Initiative for the VAPP/VDPV Elimination Phase
  23. 24. Polio status in South Africa <ul><li>Last lab confirmed case was in 1989 </li></ul><ul><li>AFP is notifiable since 1994 </li></ul><ul><li>Case-based surveillance since 1995 </li></ul><ul><li>4 strategies </li></ul><ul><li>High routine coverage with OPV </li></ul><ul><li>Mass immunisation campaigns </li></ul><ul><li>‘ Mopping-up’ campaigns </li></ul><ul><li>AFP surveillance </li></ul>
  24. 25. <ul><li>National immunisation campaigns 1995, 1996, 1997, 2000 (2002 = WC), 2004, 2007 </li></ul><ul><li>SA: national certificate in Oct 2006 </li></ul><ul><li>Target for 2008: AFP detection rate of at least 2/100,000 </li></ul><ul><li>SA 2008: AFP 2/100,000, stool adeq 82% </li></ul><ul><li>WC 2008: AFP 2,3/100, 000 </li></ul><ul><li>Stool adequacy 96% </li></ul><ul><li>************************************************** </li></ul>