1 / 14

WHO Draft Rapid Response + Containment, May 2006

WHO Draft Rapid Response + Containment, May 2006. Projected Outbreak of H5N1 in Thailand. R 0 = 1.5. Red = new cases. Green = areas where the epidemic has finished. Ferguson et al. Nature 437:209, 2005.

hali
Télécharger la présentation

WHO Draft Rapid Response + Containment, May 2006

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. WHO Draft Rapid Response + Containment, May 2006

  2. Projected Outbreak of H5N1 in Thailand R0 = 1.5 Red = new cases. Green = areas where the epidemic has finished. Ferguson et al. Nature 437:209, 2005

  3. Left: uncontrolled outbreak. Red = new cases. Green = areas where the epidemic has finished. Above: Controlled outbreak. Red = areas of infection. Blue = areas where a combination of control measures implemented. Projected Outbreak of H5N1 Influenza in Thailand http://www.nigms.nih.gov/news/releases/08032005.html

  4. Elimination of a pandemic virus at its source? • Ring chemoprophylaxis feasible if: • Geographically targeted in non-urban setting • Early intervention within 1-3 wks • Virus of low-moderate transmissibility (R0 < 1.8) • Chemoprophylaxis of 80 - 90% of population • High compliance • Movement restrictions; social distancing • Maximum of 1-3 million courses needed • 300,000 may be sufficient Ferguson et al. Nature 437:209, 2005

  5. Rapid Response: Antiviral Deployment • Rapid use of antiviral prophylaxis is key component. • Mass targeted antiviral prophylaxis: • Goal of 90% coverage • Geographic radius of 5-10 km from each detected case OR • Administrative area of “at-risk” population of 10-50,000 • Multiple logistical hurdles • WHO donation of 3.0 M courses • 440 courses = 7.8 kg • 100,000 courses = 19 shipping pallets • Start dispensing within 12 hrs of receipt WHO Draft Rapid Response + Containment Document, May 2006

  6. Antiviral Resistance in Influenza Viruses • M2 inhibitors: • Primary resistance in epidemic (>90% of recent H3N2) or pandemic virus possible; frequent with Rx • Confers cross-resistance to entire class • Resistant variants virulent and transmissible • NA inhibitors: • No primary resistance; active for all 9 NA types • Inhibitory for M2 resistant-variants • Variable NAI cross-resistance depending on type/subtype and drug • Most NAI resistance causes infectivity and virulence in animals NISN. Weekly Epi Record 33:306, 2004

  7. Detection Of Antiviral Resistant Influenza During Treatment Roberts N. Phil Trans R Soc Lond 356:1895, 2001 Kiso et al. Lancet 364: 759, 2004

  8. Pharyngeal Viral Loads during Oseltamivir Treatment of H5N1 de Jong et al. NEJM 353:25, 2005

  9. Neuraminidase Inhibitor Treatment : Antiviral Resistance • Emergence of oseltamivir-resistant variants may be associated with prolonged viral detection in A/H3N2-infected children and in H5N1-infected patients. • Resistance due to H274Y mutation may compromise clinical efficacy in some H5N1 patients. • No transmission of oseltamivir-resistant variants detected in house-hold based studies or in prophylaxis failures to date. • Some resistant variants are transmissible in ferret model (including H274Y mutation in N1)

  10. Influenza Prevention In Households: PEP *Index case given treatment

  11. Interval from PEP Initiation to Secondary Illness Onset in Household Contacts (N = 1,291) Note: zanamivir PEP started < 36 hr of index illness onset Monto et al. JID 186:1582, 2002

  12. Influenza Post-exposure Prophylaxis (PEP) with Neuraminidase Inhibitors: Summary • Socially targeted antiviral prophylaxis (PEP) is highly effective in protecting contacts in households during seasonal influenza. • Reductions in illness > infection. • Secondary cases occur early, often in first few days after index case recognition. • Rapid initiation is essential. • Inhaled zanamivir is also effective for prevention. • Unstudied in human H5N1 infections to date.

  13. Rapid Response: Antiviral Deployment • Mass targeted antiviral prophylaxis: • Goal of 90% coverage • Geographic radius of 5-10 km from each detected case OR • Administrative area of “at-risk” population of 10-50,000 • Minimal duration of 10 days • Multiple logistical hurdles • 100,000 courses = 19 shipping pallets • Start dispensing within 12 hrs of receipt WHO Draft Rapid Response + Containment Document, May 2006

More Related