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Lessons for Europe from past pandemics and the North American experience so far

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  • Lessons for Europe from past pandemics and the North American experience so far

    Lessons for Europe from past pandemics and the North American experience so far

    some good slides, graph


  • #2
    Re: Lessons for Europe from past pandemics and the North American experience so far

    Merci Anne!

    Comment


    • #3
      Re: Lessons for Europe from past pandemics and the North American experience so far

      This is the html version of the file http://ecdc.europa.eu/en/Health_topi...alk_090618.ppt.
      Google automatically generates html versions of documents as we crawl the web.
      Lessons for Europe from past pandemics and the North American experience so far


      Evolution of the pandemic of
      A(H1N1)v influenza


      European Centre for Disease Prevention and Control

      Based on a talk given on 11 May 2009 in Stockholm to
      ECDC?s Advisory Forum

      2


      About this presentation


      This is an open-access ECDC Educational PowerPoint presentation arranged in modules for use by professional explaining about the new A(H1N1)v virus to other professionals and policy makers. The slides should always be viewed with their accompanying notes, and ?cutting and pasting? is not recommended.

      A number of the slides will change with time. The slides are updated at intervals and the user should periodically check for updates available on the ECDC website:




      Comments on the slides and the notes are very much welcomed to be sent to influenza@ecdc.europa.eu.

      Please state "Pandemic PowerPoints" in the subject line when writing to us.


      ECDC thanks the National Institute of Infectious Diseases, Japan, for the original work on Slide 3, and the Centers for Disease Control and Prevention, USA, for the original idea in Slide 27.

      3


      Pandemics of influenza


      H7


      H5


      H9*


      1980


      1997


      Recorded new avian influenzas


      1996


      2002


      1999


      2003


      1955


      1965


      1975


      1985


      1995


      2005


      H1N1


      H2N2


      1889

      Russian

      influenza

      H2N2


      H2N2


      1957

      Asian

      influenza

      H2N2


      H3N2


      1968

      Hong Kong

      influenza

      H3N2


      H3N8


      1900

      Old Hong Kong influenza

      H3N8


      1918

      Spanish

      influenza

      H1N1


      1915


      1925


      1955


      1965


      1975


      1985


      1995


      2005


      1895


      1905


      2010


      2015


      2009

      Novel

      influenza

      H1N1v


      Recorded human pandemic influenza
      (early sub-types inferred)


      Reproduced and adapted (2009) with permission of Dr Masato Tashiro, Director, Center for Influenza Virus Research,
      National Institute of Infectious Diseases (NIID), Japan.


      Animated slide: Press space bar


      H1N1


      H1N1v

      4


      The situation could be a lot worse
      for Europe! (Situation circa summer 2009)


      A pandemic strain emerging in the Americas
      Immediate virus sharing so rapid diagnostic and vaccines
      Based on A(H1N1)v currently not that pathogenic
      Some seeming residual immunity in a major large risk group
      No known pathogenicity markers
      Initially susceptible to oseltamivir
      Good data and information coming out of
      North America
      Arriving in Europe in the summer
      Milder presentation initially


      A pandemic emerging in SE Asia


      Delayed virus sharing


      Based on a more pathogenic strain, e.g. A(H5N1)


      No residual immunity


      Heightened pathogenicity


      Inbuilt antiviral resistance


      Minimal data until transmission reached Europe


      Arriving in the late autumn or winter


      Severe presentation immediately


      Contrast with what might have happened ? and might still happen!

      5


      But no room for complacency
      (Situation and information: late May 2009)


      Pandemics take some time to get going (1918 and 1968).
      Some pandemic viruses have ?turned nasty? (1918 and 1968).
      Is the ?mildness? and the lack of older patients because older people are resistant or because the virus is not transmitting much among them?
      There will be victims and deaths ? as in the US ? in risk groups (young children, pregnant women and especially people with other underlying illnesses).
      As the virus spreads south, will it exchange genes with seasonal viruses that are resistant: A(H1N1)-H247Y, more pathogenic A(H3N2), or even highly pathogenic A(H5N1)?
      An inappropriate and excessive response to the pandemic could be worse than the pandemic itself.
      6


      Idealised curve for planning


      Single wave profile showing proportion of new clinical cases, consultations, hospitalisations or deaths by week. Based on London, 2nd wave 1918.


      0%


      5%


      10%


      15%


      20%


      25%


      1


      2


      3


      4


      5


      6


      7


      8


      9


      10


      11


      12


      13


      14


      15


      Week


      Proportion of total cases, consultations, hospitalisations or de


      aths


      Source: Department of Health, UK


      Initiation Acceleration Peak Declining


      Animated slide: Please wait

      7


      One possible European scenario ? summer 2009


      In reality, the initiation phase can be prolonged, especially in the summer months. What cannot be determined is when acceleration takes place.


      0%


      5%


      10%


      15%


      20%


      25%


      Apr


      May


      Jun


      Jul


      Aug


      Sep


      Oct


      Nov


      Dec


      Jan


      Feb


      Mar


      Month


      Proportion of total cases, consultations, hospitalisations or deaths


      Initiation Acceleration Peak Declining


      Animated slide: Please wait


      Apr

      8





      How pandemics differ ?
      and why they can be difficult

      9


      For any future pandemic virus ? what can and cannot be assumed?


      What probably can be assumed:

      Known knowns

      Modes of transmission (droplet, direct and indirect contact)
      Broad incubation period and serial interval
      At what stage a person is infectious
      Broad clinical presentation and case definition (what influenza looks like)
      The general effectiveness of personal hygiene measures (frequent hand washing, using tissues properly, staying at home when you get ill)
      That in temperate zones transmission will be lower in the spring and summer than in the autumn and winter


      What cannot be assumed:

      Known unknowns

      Antigenic type and phenotype
      Susceptibility/resistance to antivirals
      Age-groups and clinical groups most affected
      Age-groups with most transmission
      Clinical attack rates
      Pathogenicity (case-fatality rates)
      ?Severity? of the pandemic
      Precise parameters needed for modelling and forecasting (serial interval, Ro)
      Precise clinical case definition
      The duration, shape, number and tempo of the waves of infection
      Will new virus dominate over seasonal type A influenza?
      Complicating conditions (super-infections)
      The effectiveness of interventions and counter-measures including pharmaceuticals
      The safety of pharmaceutical interventions
      10


      Some of the 'known unknowns' in
      the 20th century pandemics


      Three pandemics (1918, 1957, 1968)
      Each quite different in shape and waves
      Some differences in effective reproductive number
      Different groups affected
      Different levels of severity including case fatality ratio
      Imply different approaches to mitigation
      11


      0%


      10%


      20%


      30%


      40%


      50%


      60%


      0


      20


      40


      60


      80


      Age (midpoint of age class)


      % with clinical disease


      1918 New York State


      1918 Manchester


      1918 Leicester


      1918 Warrington & Wigan


      1957 SE London


      1957 S Wales


      1957 Kansas City


      1968 Kansas City


      With thanks to Peter Grove, Department of Health, London, UK


      Age-specific clinical attack rate in previous pandemics


      Animated slide: Press space bar

      12


      Different age-specific excess deaths in pandemics


      0


      2000


      4000


      6000


      8000


      10000


      12000


      14000


      16000


      0-4


      5-9


      10-14


      15-19


      20-24


      25-34


      35-44


      45-54


      55-64


      65-74


      75+


      Age group


      Excess deaths


      0


      500


      1000


      1500


      2000


      2500


      3000


      3500


      4000


      <1


      1-2


      2-5


      5-10


      10-15


      15-20


      20-25


      25-35


      35-45


      45-55


      55-65


      65-75


      75+


      Age group


      Excess deaths


      Excess deaths, second wave, 1918 epidemic


      Excess deaths second wave 1969 pandemic, England and Wales


      Source: Department of Health, UK

      13


      1918/1919 pandemic: A(H1N1)
      influenza deaths, England and Wales


      1918/19: ?Influenza deaths?, England and Wales.
      The pandemic affected young adults, the very young and older age groups.


      0


      2,000


      4,000


      6,000


      8,000


      10,000


      12,000


      14,000


      16,000


      18,000


      27


      29


      31


      33


      35


      37


      39


      41


      43


      45


      47


      49


      51


      2


      4


      6


      8


      10


      12


      14


      16


      18


      1918


      1919


      Week no. and year


      Deaths in England and Wales


      Ro = 2-3 (US) Mills, Robins, Lipsitch (Nature 2004)

      Ro = 1.5-2 (UK) Gani et al (EID 2005)

      Ro = 1.5-1.8 (UK) Hall et al (Epidemiol. Infect. 2006)

      Ro = 1.5-3.7 (Geneva) Chowell et al (Vaccine 2006)


      Courtesy of the Health Protection Agency, UK


      Transmissibility: estimated Basic Reproductive Number (Ro)

      14


      Estimated additional deaths in Europe if a 1918/19 pandemic occurred now ?
      a published worst case scenario


      5,800


      Norway


      420


      Iceland


      93,000


      UK


      1,100


      Malta


      89,600


      France


      13,300


      Sweden


      500


      Luxembourg


      8,100


      Finland


      87,100


      Spain


      95,200


      Italy


      6,100


      Estonia


      20,600


      Slovakia


      6,700


      Ireland


      7,300


      Denmark


      5,000


      Slovenia


      37,700


      Hungary


      1, 900


      Cyprus


      149,900


      Romania


      27,400


      Greece


      34,100


      Czech Rep


      25,100


      Portugal


      116,400


      Germany


      47,100


      Bulgaria


      155,200


      Poland


      18,800


      Lithuania


      14,900


      Belgium


      23,100


      Netherlands


      13,800


      Latvia


      13,000


      Austria


      EU total: 1.1 million


      Murray CJL, Lopez AD, Chin B, Feehan D, Hill KH. Estimation of potential global pandemic influenza mortality on the basis of vital registry data from the 1918?20 pandemic: a quantitative analysis. Lancet. 2006;368: 2211-2218.

      15


      1957/1958 pandemic: A(H2N2) ?
      especially transmitted among children


      Ro = 1.8 (UK) Vynnycky, Edmunds (Epidemiol. Infect.2007)

      Ro = 1.65 (UK) Gani et al (EID 2005)

      Ro = 1.5 (UK) Hall et al (Epidemiol. Infect. 2006)

      Ro = 1.68 Longini et al (Am J Epidem 2004)


      0


      200


      400


      600


      800


      1,000


      6


      13


      20


      27


      3


      10


      17


      24


      31


      7


      14


      21


      28


      5


      12


      19


      26


      2


      9


      16


      23


      30


      7


      14


      21


      28


      4


      11


      18


      25


      1


      8


      15


      22


      July


      August


      September


      October


      November


      December


      January


      February


      Week number and month during the winter of 1957/58


      Recorded deaths in England and Wales from


      influenza


      1957/58: ?Influenza deaths?, England and Wales


      Courtesy of the Health Protection Agency, UK


      Transmissibility: estimated Basic Reproductive Number (Ro)

      16


      1968/1969 pandemic: A(H3N2) ? transmitted and affected all age groups


      Ro = 1.5-2.2 (World) Cooper et al (PLoS Med.2006)

      Ro = 2.2 (UK) Gani et al (EID 2005)

      Ro = 1.3-1.6 (UK) Hall et al (Epidemiol. Infect. 2006)


      1968/69: GP consultations, England and Wales


      0


      200


      400


      600


      800


      1,000


      1,200


      1,400


      42


      48


      4


      12


      20


      28


      36


      44


      50


      8


      16


      24


      32


      40


      48


      4


      12


      20


      28


      36


      1967


      1968


      1969


      1970


      Week no. and year


      GP 'ILI' consultations per week


      Courtesy of the Health Protection Agency, UK


      Initial
      appearance


      Seasonal
      influenza


      Transmissibility: estimated Basic Reproductive Number (Ro)

      17


      Differing attack rates determined by serology: serological attack rate observed in the UK


      0%


      10%


      20%


      30%


      40%


      50%


      60%


      70%


      80%


      90%


      100%


      0-9


      10-19


      20-29


      30-39


      40-49


      50-59


      60-69


      70-79


      1969 (first wave)


      1970 (second wave)


      1957


      Courtesy of the Health Protection Agency, UK

      18


      Idealised curves for local planning


      In reality, larger countries can experience a series of shorter but steeper local epidemics.


      0%


      5%


      10%


      15%


      20%


      25%


      1


      2


      3


      4


      5


      6


      7


      8


      9


      10


      11


      12


      13


      14


      15


      Week


      Proportion of total cases, consultations, hospitalisations or de


      aths


      Animated slide: Press space bar

      19


      0%


      5%


      10%


      15%


      20%


      25%


      30%


      35%


      40%


      45%


      1918 New


      York State


      1918


      Leicester


      1918


      Warrington


      and Wigan


      1957 SE


      London


      1968


      Kansas City


      clinical attack rate (%)


      Numbers affected in seasonal influenza epidemics and pandemics (overall clinical attack rate in previous pandemics)


      Seasonal
      influenza

      20


      Seasonal influenza compared to pandemic ? proportions of types of cases


      Asymptomatic





      Clinical
      symptoms


      Deaths


      Requiring
      hospitalisation


      Seasonal influenza


      Pandemic


      Asymptomatic


      Clinical
      symptoms


      Deaths


      Requiring
      hospitalisation

      21





      Initial experience in
      North America 2009

      22


      Emerging themes in North America, early June 2009 (1)


      Early epidemic:
      increased influenza-like illness reports due to increased consultations;
      many cases attributable to seasonal influenza until mid-May.
      Infection rate for probable and confirmed cases highest in 5−24 year age group.
      Hospitalisation rate highest in 0−4 year age group, followed by 5−24 year age group.
      Pregnant women, some of whom have delivered prematurely, have received particular attention but data inadequate to determine if they are at greater risk from H1N1v than from seasonal influenza as already established.
      Most deaths in 25−64 year age group; most with known risks for severe disease.
      Obesity suggested as risk but may be indicator for pulmonary risk.
      Adults, especially 60 years and old, may have some degree of preexisting cross-reactive antibody to the novel H1N1 flu virus.
      Transmission persists in several regions of the US with increased or rising incidence in New York area and northeastern US.
      23


      Emerging themes in North America, early June 2009 (2)


      Containment impossible with multiple introductions and R0 1.4 to 1.6.
      Focus on counting laboratory-confirmed cases changing to seasonal surveillance methods.
      Outpatient influenza-like illness, virological surveillance (including susceptibility), pneumonia and influenza mortality, pediatric mortality and geographic spread.
      Serological experiments and epidemiology suggest 2008?2009 seasonal A(H1N1) vaccine does not provide protection.
      Preparing for the autumn and winter when virus is expected to return:
      communications: a pandemic may be 'mild' yet cause deaths;
      25% of U.S. stockpile deployed to states (includes medication and equipment);
      determining if and when to begin using vaccine;
      school closures being analyzed to determine effectiveness;
      other domestic and international investigations of public health questions.
      24





      Measuring the severity of a pandemic

      25


      There is an expectation that pandemics should be graded by severity


      But there are difficulties:

      severity varies from country to country;
      it can change over time;
      some relevant information is not available initially;
      key health information includes medical and scientific information:
      epidemiological, clinical and virological characteristics.
      There are also social and societal aspects:
      vulnerability of populations;
      capacity for response;
      available health care;
      communication; and
      the level of advance planning.
      26


      What is meant by 'mild' and 'severe'?
      Not a simple scale


      Death ratio. Expectation of an infected person dying (the Case Fatality Ratio).
      Number of people falling ill with respiratory illnesses at one time ? 'winter pressures'. Pressure on the health services' ability to deal with these ? very related to preparedness and robustness.
      Critical service functioning. Peak prevalence of people off ill or caring for others.
      Certain groups dying unexpectedly, e.g. children, pregnant women, young healthy adults.
      Public and media perception
      Conclusions. Not easy to come up with a single measure.
      May be better to state what interventions/countermeasures are useful and justifiable (and what are not).



      http://www.who.int/csr/disease/swine.../en/index.html and http://www.who.int/wer/2009/wer8422.pdf

      27





      Arguments for and against just undertaking mitigation and not attempting delaying or containment

      28


      Policy dilemma ? mitigating vs. attempting delaying (containing) pandemics?


      Arguments for just mitigating and not attempting delaying or containment:

      Containment specifically not recommended by WHO in Phases 5 & 6.
      Was not attempted by the United States for this virus.
      Delaying or containment cannot be demonstrated to have worked ? would have seemed to have worked in 1918 and 1968 without doing anything.
      Very labour-intensive ? major opportunity costs.
      Will miss detecting sporadic transmissions.
      Overwhelming numbers as other countries ?light up?.
      When you change tactic, major communication challenge with stopping prophylaxis.
      29


      Policy dilemma ? mitigating vs. attempting delaying (containing) pandemics?


      Arguments for case-finding, contact tracing and prophylaxis:

      Countries are then seen to be doing something.
      Recommended in one specific circumstance by WHO (the rapid containment strategy).
      There are some places it would work in Europe (isolated communities).
      It is what public health people do for other infections.
      Public may expect it.
      30


      With interventions


      Aims of community reduction of influenza transmission ? mitigation


      Delay and flatten epidemic peak
      Reduce peak burden on healthcare system and threat
      Somewhat reduce total number of cases
      Buy a little time


      Daily

      cases


      Days since first case


      No intervention


      Animated slide: Press space bar


      Based on an original graph developed by the US CDC, Atlanta
      I'm interested in expert panflu damage estimates
      my current links: http://bit.ly/hFI7H ILI-charts: http://bit.ly/CcRgT

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