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What we need to know about influenza

What we need to know about influenza. Family Medicine Forum October 28, 2009. Speakers. Jim Dickinson MBBS CCFP PhD FRACGP Professor of Family Medicine, U Calgary Director Tarrant Viral Watch Kevin Fonseca PhD D(ABMM) Clinical Virologist, Provincial Laboratory

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What we need to know about influenza

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  1. What we need to know about influenza Family Medicine Forum October 28, 2009

  2. Speakers Jim Dickinson MBBS CCFP PhD FRACGP Professor of Family Medicine, U Calgary Director Tarrant Viral Watch Kevin Fonseca PhD D(ABMM) Clinical Virologist, Provincial Laboratory Andre Corriveau MD MBA FRCPC Chief Medical Officer of Health Alberta.

  3. Outline • Where are we now? • Laboratory issues: What is this virus? • Clinical response • Protection and prevention • Vaccines and antivaccine arguments • Current best available science • Observing & Inventing as we go along

  4. Outline • Where are we now? • Laboratory issues: What is this virus? • Clinical response • Protection and prevention • Vaccines and antivaccine arguments

  5. Alberta’s Response toPandemic (H1N1) 2009 Influenza André Corriveau, MD, MBA, FRCPC Chief Medical Officer of Health Alberta Health and Wellness October 29, 2009

  6. Influenza Affects Us Every Year • Fever and cough (1 week) Sore throat, malaise, muscle aches, headaches • Pneumonia, exacerbation of underlying chronic illnesses, encephalitis • 1 - 4 out of 10 persons ill with flu each year • Globally, +/- 0.5million deaths / year +/- 4,000 in Canada • More severe illness typically seen in the very old and the very young, although other risk factors also recognized (pregnancy, lung disease, smoking, etc.)

  7. Flu pandemics in history 1918/19: Spanish Flu (H1N1) 40-50 million deaths 1957: Asian flu (H2N2) 1 million deaths 1968: Hong Kong flu (H3N2) 1 million deaths

  8. Pandemic (H1N1) 2009 Influenza Virus • Pandemic (H1N1) 2009 virus – new strain • Subtype of influenza A virus • Re-assortment of human, swine, and avian influenza A viruses • Limited population immunity • Viral replication occurs more readily in lung tissue than seen with other influenza strains • Virus does not appear to be changing

  9. Pandemic (H1N1) 2009 Influenza – Clinical Characteristics • Generally mild symptoms, similar to seasonal influenza • Acute onset of respiratory symptoms • Fever and cough and one or more of: sore throat, muscle aches, joint pain, or weakness • Gastrointestinal symptoms may also be present, more often in children • Small subset of people develop severe respiratory infection requiring support in intensive care unit

  10. Pandemic (H1N1) 2009 Influenza – Transmission Similarly to seasonal influenza: • Predominantly through droplets dispersed by coughing or sneezing • Indirect transmission through self-inoculation after contact with surfaces and objects contaminated with the virus from infected persons

  11. Declaration of a pandemic • The World Health Organization (WHO) Issues the Declaration • Was done on June 11, 2009 • The Declaration triggers: • Vaccine development • Enhanced surveillance • Planning of immunization strategy • Planning for release of antiviral & other stockpiles • Enhanced communication activities

  12. Pandemic H1N1 Summary in Alberta(as of October 26, 2009) • 3,052 laboratory confirmed cases • 190 hospitalized • 12 deaths • 53% female • Median age is 19 years • Vast majority of respiratory outbreaks this fall have occurred in schools

  13. Pandemic H1N1 Summarycontinued… • Younger Population Affected All Confirmed Cases • Age range: 1 month - 99 years • Median Age: 19 years Hospitalized • Age Range: 1 month - 89 years • Median Age: 32 years Deaths • Age Range: 25 – 90 years • Median Age: 48.5 years

  14. Epi Curve of Cases in Alberta by Date Specimen Collected

  15. Total Confirmed 31 cases (out of 3,052) or 1% Age range: 4 months to 66 years Median age is 25 years Hospitalized 20 cases (out of 190) or 10.5% Age range: 4 months to 50 years Median age is 25.5 years Deaths 3 cases (out of 12) or 25% Age range: 25 years to 43 years Median age is 39 years 5 cases ICU 2 cases Ventilated 12 cases Diagnosed with Pneumonia 12 cases with underlying conditions 9 Asthma or Chronic lung disease 3 immune-suppressed 3 diabetes or heart disease 2 pregnant * Some cases have more than one underlying condition Aboriginal Summary(as of October 26, 2009)

  16. Underlying Conditions Hospitalized 150 out of 190 cases had one or more conditions Deaths 11 out of 12 deaths had one or more conditions Underlying Conditions(as of October 26, 2009) * Totals due not add to 100% due to some cases having more than one condition

  17. Pandemic H1N1 Cases Admitted to ICU • Severe Cases About 22% or 42/190 hospitalized cases were admitted to ICU • Age range: 5 years - 79 years • Median Age: 39 years • Gender split equally (50/50) • 5 cases were Aboriginal Underlying Conditions • 63% had at least one underlying condition, with 56% of those cases having either asthma or another chronic lung disease • 40% had diabetes Deaths • 8 cases admitted to ICU died

  18. Influenza Like Illness seen through TARRANT Sentinel Sites, 2009, Alberta

  19. Outline • Where are we now? • Laboratory issues: What is this virus? • Clinical response • Protection and prevention • Vaccines and antivaccine arguments

  20. See separate presentation: • Fonseca

  21. Outline • Where are we now. • Laboratory issues: What is this virus? • Clinical response • Protection and prevention • Vaccines and antivaccine arguments

  22. How should we respond clinically? • How accurate are physicians at diagnosing a patient with influenza-like illness? • How should we treat? • How do we protect our staff and ourselves?

  23. Case Example Early May, 24 year old girl • High fever, cough, very unwell • No recent travel • Swab taken, Oseltamivir prescribed • Too ill to live on own, cared for at parents house. • Slept 20hrs/day for 2 days then slowly recovered • Swab was negative for all viruses

  24. How do we know it is Influenza? • Diagnostic testing: delay, ? available • Epidemiological information Surveillance Program • Goal of Tarrant Viral Watch: Detect Influenza-Like Illness (ILI) as it occurs in the community, and measure influenza virologically in the lab

  25. Influenza Surveillance: Alberta • ProvLab tests for: • Influenza A (including pH1N1) • Influenza B • Respiratory syncytial virus • Adenovirus • Enterovirus/rhinovirus • Coronavirus • Parainfluenza virus • Human metapneumovirus

  26. Influenza Surveillance: Alberta Tarrant Viral Watch: • Recruits sentinel physicians and nurse practitioners from Family Medicine practices in Alberta • Currently has 77 sentinel sites in the network representing all former health regions of the province. Some gaps.

  27. Influenza Surveillance: Alberta • Fundamental step in developing a surveillance system: • CASE DEFINITION • Classical definition of influenza-like illness: FEVER AND COUGH AND ONE OF: sore throat, myalgia, arthralgia, prostration

  28. Influenza Surveillance: Alberta • Every week, sentinels take a nasopharyngeal swab from at least 2 patients with ILI • Currently doing heightened surveillance: swab all ILI patients!

  29. Influenza Surveillance: Alberta • Lab results are sent to the physician for patient care, and to Tarrant Viral Watch for surveillance purposes. • Data is compiled by Tarrant Viral Watch prior to being forwarded to: • Alberta Health and Wellness; • The Public Health Agency of Canada; and • The World Health Organization.

  30. Influenza Surveillance: Canada • FluWatch: network of sentinel labs, primary care practices, ministries of health, and pediatric hospitals. Reports on: • Sentinel ILI consultation rates • Regional influenza activity levels • Work/school absenteeism • Lab-based virus detections • Strain identification and antiviral resistance • Pediatric influenza-related hospital admissions/mortality

  31. 1. Influenza Surveillance: Canada • FluWatch animated maps:

  32. Diagnostic Accuracy • How accurate are physicians at diagnosing a patient with influenza-like illness?

  33. Physician Diagnostic Accuracy • Challenges: • Vague ILI definition • Compared with seasonal influenza, pH1N1 causes different symptoms • More diarrhoea/GI upsets • Less fever

  34. N= 105 158 132 132 172 122 123 74 85 54

  35. How should we treat? • Oseltamivir (Tamiflu) tablets • Zanamivir (Relenza) inhalation • Best during replication phase: <72 hrs • Severe cases, LRTI, replication continues • Caution about prophylactic treatment • Development of drug resistance. • Details: Rx Files • Drug side effects: at least 10% • High risk, high probability

  36. New pH1N1 Chart Book or Online www.RxFiles.ca

  37. Who is at risk?: Usual suspects • Elderly: but those over 60 may be immune • Pre 1957 viruses • Young children: under age 2yrs • Healthy pregnant women: 2nd & 3rd trimester • Chronic Health conditions • Cardiac, pulm., diabetes & metabolic diseases, ,Immune deficiency &immune suppression, cancer, renal disease, anemia or hemoglobinopathy. • Poor living conditions: • Some First Nations, immigrants, street people

  38. Who is at high risk? ICU cases across Canada Young adults: mean age 32.4 Females: 67% Children: 30% Aboriginal: 25.6% 4 days from onset to ICU admission (Inter-Quartile Range 2-7days) Kumar et al. JAMA 2009;302(17)1496

  39. Acute Resp Illness Hospitalisation rates in Hunter/New England region during 2009 influenza outbreak compared with peak months in 2007 & 2008 3 winter months: June – August Hospitalisations: • 1736 9.7/10,000 • 1267 5.8/10,000 • 2378 11.4/10,000 Dawood et al Med J Aust 2009 26 Oct

  40. Acute Resp Illness Hospitalisation rates in Hunter/New England region during 2009 influenza outbreak, compared with peak months in 2007 & 2008 Dawood et al Med J Aust 2009 26 Oct

  41. Who should be treated? • Patients want treatment • Guidelines suggest only severe cases, or high risk be treated • Drug most useful if given early • Not so useful if wait till severe • ??? • Clinical judgment in face of uncertainty

  42. Prescribing for pneumonia • Suggest add antibiotics in patients with: • Resp rate >25 • Pulse >100

  43. Outline • Where are we now. • Laboratory issues: What is this virus? • Clinical response • Protection and prevention • Vaccines and antivaccine arguments

  44. Sequence of care • Patient phones with symptoms • Receptionist triage • Patient arrives • Mask and hygeine • Immediate transfer to isolation room • Assessment • ? Protection level • Diagnosis & treatment • Follow-up

  45. How should we protect ourselves? • Science of infection control: probabilities • How spread occurs • Respiratory secretions • Mostly droplets: range 1 meter • Aerosols: longer, penetrate into resp tract • Surgical masks stop droplets: exit • N95 masks reduce aerosols: inhalation • Difficult to use, hard to work in. Council of Canadian Academies:2008

  46. How should we protect ourselves? • Ocular mucosa: unclear • Visors or goggles • Most important • Hand transmission • From patient, to people and surfaces • Gloves and hand-washing • Destroyed by soap and water

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