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Pandemic or Panic?

Pandemic or Panic?. Influenza A (H1N1) Jennifer Hughes May 21, 2009. Outline. Influenza outbreaks, epidemics and pandemics Epidemiology of novel H1N1 SOIV Our local picture Vaccine Things you should know about treatment. Epidemic:

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Pandemic or Panic?

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  1. Pandemic or Panic? Influenza A (H1N1) Jennifer Hughes May 21, 2009

  2. Outline • Influenza outbreaks, epidemics and pandemics • Epidemiology of novel H1N1 SOIV • Our local picture • Vaccine • Things you should know about treatment

  3. Epidemic: From the Greek epi (upon) + demos (people): affecting a disproportionately large number of individuals within a population at the same time. Pandemic: pan (all) + demos (people): occurring over a wide geographic area.

  4. Influenza • High attack rates • Low mortality (on average) – 0.1% - 20% • More people have died from influenza in a short period time than from any other disease. • Affects birds and mammals

  5. Influenza A • Surface glycoproteins: • HA (hemoagglutinins) • NA (neuraminidases) • H1, H2, H3 • N1, N2

  6. A typical flu year • Two flu seasons (one per hemisphere) • 2-5 million cases of severe illness • 500,000 deaths worldwide • Annual pandemic?

  7. Putting it in perspective

  8. Remember H5N1 ? • Avian-adapted, highly pathogenic • Endemic and panzootic in birds • Not efficiently or sustainably transmitted to humans or between humans • 2008 : 44 cases, 33 deaths (75% mortality) • 2009: 29 cases, 11 deaths (38% mortality)

  9. SARS for comparison • SARS coronavirus • Near pandemic between Nov 2002 – July 2003 • 8096 cases, 774 deaths • Case fatality rate 9.6% • Last human case 2003 • “fully contained”

  10. y

  11. Tracing the beginning • March 18 – Mexico reports increase in late-season ILI • April 21 samples are sent to CDC to confirm • First death April 13 • Diabetic woman from Oaxaca • 2 Children San Diego country diagnosed April 24

  12. Mexico • 3648 cases • 72 deaths • Hospitalization rates high in young people • Surveillance challenging

  13. H1N1 outbreak: what is known • Novel virus (to animals and humans) • No pre-existing immunity • More contagious than seasonal influenza • Primary attack rate 35% • Unclear origin

  14. Mild illness (except Mexico) • Severe and lethal cases seen in younger patients • Case fatality rate estimate of 0.3-1.4% • Could result in 6-12 million deaths WHO Rapid Pandemic Assessment Collaboration

  15. The current H1N1 SOIV situation… • 21 May 2009 06:00 • 41 countries • 11 034 cases • 85 deaths • 791 cases since May 20 • 5 new deaths

  16. Surveillance in Canada

  17. Alberta’s cases • 30 had traveled to affected areas; • 9 in contact with travelers • 16 no travel history • 31 cases have travel/exposure histories to be determined. • Median 33 years of age

  18. Gift Lake, Alberta • Woman in 30s with chronic underlying medical conditions • No travel to Mexico • Household contact + H1N1 SOIV • Died in Edmonton April 28, 2009 • Autopsy report May 14 : inconclusive about role of H1N1

  19. Reverse Zoonosis in Alberta • Rocky Mountain House • 2200 pigs under quarantine • “some” animals had Influenza A H1N1 • From carpenter who traveled to Mexico • 500 culled for overcrowding

  20. Testing • NP swab or aspirate • M5 Universal Transport Medium • “Influenza testing” on ProvLab req (mark as “EI 236”) • Prov Lab requisition

  21. Across the Region • PLC • ACH • FMC • RGH

  22. Laboratory Diagnosis • Confirmed case definition: • RT-PCR • Viral culture • 4 x increase in H1N1 specific neutralizing AB • Probable case: • Positive testing for influenza A • Untypable, with/without clinical sx

  23. Reporting • Mild ILI – report if you swabbed them • Severe - call MOH on call • Positive results followed by public health

  24. Infection Prevention & Control • Patients • Health care workers • Site to site

  25. Respiratory Precautions • Within 2 m of patient • Surgical mask • Patient is compliant with resp hygiene • Weak or no cough • N95 mask • Aerosol-generating medical procedures • Non-compliant patient

  26. Swine Flu Kit for $39.95 (+ $8.95 shipping)

  27. Vaccine • Current seasonal flu vaccine: no immunity • H1N1 vax available in 5-6 months • Global capacity of 1-2 billion doses/year • Will not be incorporated into seasonal vaccine • 1 vs 2 doses? • Federal gov + GlaxoSmithKline have signed a deal for Canadian Production

  28. Treatment • Oseltamivir (Tamiflu): Roche • Zanamivir (Relenza) : GlaxoSmithKline • Neuraminidase inhibitor : prevents virion release from infected cells • Age-based, weight-based dosing in children • Pregnancy Category C • Most effective when started within 48 hours

  29. Oseltamivir • 25-30% reduction in symptom duration • 59% reduction in hospitalization • 63% reduction in antimicrobial use • 1 day reduction in work days lost • Reduction in mortality (OR 0.21, p<0.03) • Statement on influenza vaccination for the 2008-2009 season. An Advisory Committee Statement (ACS). Can Commun Dis Rep 2008 Jul 15;34(ACS-3):1-46.  Available at:  http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/08pdf/acs-3.pdf • Centers for Disease Control and Prevention. Antiviral agents for seasonal influenza:  dosage. 2009 [updated 2009 Feb 11, cited 2009 Mar 20]. Available at: http://www.cdc.gov/flu/professionals/antivirals/dosage.htm

  30. Oseltamivir in Canada • NOT RECOMMENDED for treatment or prophylaxis of mild cases • Tamiflu use should be consistent with use for seasonal influenza

  31. Indications for Tamiflu • All hospitalized patients with confirmed, probable or suspected influenza (novel or seasonal) • Patients who are at higher risk for seasonal influenza complications

  32. Indications for Tamiflu • Influenza-like illness • < 48 hours onset • High risk of influenza-related complications • cardiac or pulmonary disorders • diabetes mellitus • cancer • immunodeficiency • renal disease • anemia or hemoglobinopathy • conditions that compromise the management of respiratory secretions • children with conditions treated for long periods with acetylsalicylic acid • children < 2 years • pregnant women • > 65 years

  33. Who should get PEP? • Close contact of case (suspected, probable and confirmed) • High risk for complications of influenza • Health care workers with recognized, unprotected close contact exposure • During infectious period (Day 0 – Day 7)

  34. Influenza Antiviral Dosing

  35. Canada’s pandemic plan • Stockpile to treat 17.5% of population • 55.7 million doses stockpiled in Canada • 5 million doses of zanamivir • Alberta would get ~10% Canadian Pandemic Influenza Plan for the Health Sector :The Use of Antiviral Drugs During a Pandemic. Public Health Agency of Canada. May 12, 2009.

  36. Oseltamivir in the Region • Available for purchase by prescription • NOT a restricted medication • Hospitals and outpatient pharmacies have stockpile for MOH cases

  37. Neuraminidase Resistance • HIN1 SOIV • 101 isolates : 0 % resistance to neuraminidase inhibitors • 96 isolates : 100% resistance to adamantanes http://www.cdc.gov/h1n1flu/recommendations.htm#table2

  38. Speculating on the future • Clinical spectrum not yet fully apparent • Spread to southern hemisphere/interaction with seasonal flu • Antigenic drift of influenza viruses

  39. H5N1 avian influenza + H1N1 = “Armageddon Virus”

  40. Assessing the severity of an influenza pandemic • Inherent virulence • Population vulnerability • Waves of spread • 8 gene segments commonly and unpredictably mutate • Capacity to respond

  41. WHO Phase 5: sustained community-level outbreaks in at least two countries in one WHO region. • Pandemic is “imminent” • Currently “sustained community-level outbreak”

  42. Staving off a pandemic? • May 18, 2009: Britain, Japan, China, US and others urge WHO to change its definition of a pandemic to reflect the virulence of a disease, not just how far it spreads around the world.

  43. Summary • First wave of the outbreak appears mild • Future is unpredictable • Still on upswing of epidemiological curve • Vaccine is still months away • Oseltamivir and zanamivir work… for now • Major political and economic impacts of pandemic

  44. References Public Health Agency of Canada. FightFlu. Http://www. Fightflu.ca. Access May 20, 2009. The Lancet: H1N1 Resource Centre: http://www.thelancet.com/H1N1-flu McGeer A, Green KA, Plevneshi A, et al. Antiviral therapy and outcomes of influenza requiring hospitalization in Ontario, Canada. Clin Infect Dis 2007;45:1568-75. Kaiser I, Wat C, Mills T, et al. Impact of oseltamivir treatment on influenza-related lower respiratory tract complications and hospitalizations. Arch Intern Med 2003;163:1667-72. Cooper NJ, Sutton AJ, Abrams KR , et al. Effectiveness of neuraminidase inhibitors in treatment and prevention of influenza A or B: systematic review and meta-analysis of controlled trials. BMJ 2003;326:1-7. Canadian Pandemic Influenza Plan for the Health Sector: The Use of Antiviral Drugs During a Pandemic. Annex E. Public Health Agency of Canada. May 12, 2009. http://www.phac-aspc.gc.ca/cpip-pclcpi/pdf-e/annex_e0513-eng.pdf Aoki FY , Macleod MD, Paggiaro P, et al. Early administration of oral oseltamivir increases the benefits of influenza treatment. J Antimicrob Chemother 2003;51:123-9. Balicer RD , Huerta M, Davidovitch N, et al. Cost benefit of stockpiling drugs for influenza pandemic. Emerg Infect Dis 2005;11:1280-2.

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