1 / 65

Flu Pandemic

Flu Pandemic. Dr. Arif Rajpura Director of Public Health NHS Blackpool. Flu Pandemic. Explaining pandemic flu History of influenza pandemics Virology Avian Influenza Predicting the impact Containing Pandemic Flu Antiviral Drugs Influenza Vaccine Final Remarks. Explaining pandemic flu.

josh
Download Presentation

Flu Pandemic

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. Flu Pandemic Dr. Arif Rajpura Director of Public Health NHS Blackpool

  2. Flu Pandemic Explaining pandemic flu History of influenza pandemics Virology Avian Influenza Predicting the impact Containing Pandemic Flu Antiviral Drugs Influenza Vaccine Final Remarks

  3. Explaining pandemic flu

  4. Understanding pandemic Epidemic: serious outbreak in a single community, population or region Pandemic: epidemic spreading around the world affecting hundreds of thousands of people, across many countries

  5. What causes pandemic flu? • Flu pandemics are global epidemics of a newly emerged strain of flu (a new influenza A subtype) • New virus passes easily from person to person • Few, if any, people have any immunity • This allows it to spread widely, easily and to cause more serious illness

  6. Who is at risk? • Everyone is at risk • Certain groups may be at greater risk of serious illness than others • Until the virus starts circulating we will not know for sure who is at most risk

  7. Is there a vaccine? • Because the virus will be new, there will be no vaccine ready to protect against pandemic flu • A specific vaccine cannot be made until the virus has been identified • Cannot be predicted in same way as ‘ordinary’ seasonal flu • ‘Ordinary’ flu vaccine or past flu jab will not provide protection

  8. What is influenza? • An acute illness resulting from infection by an influenza virus • Highly infectious • Can spread rapidly from person to person • Some strains cause more severe illness than others

  9. Symptoms • Generally of sudden onset • Fever, headache, aching muscles, severe weakness • Respiratory symptoms e.g. cough, sore throat, difficulty breathing

  10. Incubation period of influenza • Estimates vary • The range described is from 1 to 4 days • Most incubation periods are in the range of 2-3 days

  11. How influenza spreads • Easily passed from person to person through coughing and sneezing • Transmitted through • breathing in droplets containing the virus, produced when infected person talks, coughs or sneezes • touching an infected person or surface contaminated with the virus and then touching your own or someone else’s face

  12. Big droplets fall on people surfaces bed clothes

  13. History of influenza pandemics

  14. History of Influenza • 412 BC - first mentioned by Hippocrates • 1580 - first pandemic described • 1580 - 1900 - 28 pandemics

  15. Circulating Influenza strains and pandemics in 20th Century 1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu” 20-40 million deaths 1 million deaths 1 milliondeaths H2N2 H3N2 H1N1 H1N1

  16. Iowa State gymnasium, converted into hospital, 1918 flu epidemic

  17. Employees of Stewart & Holmes Wholesale Drug Co. Seattle, 1918 Courtesy of Grace Loudon Mc Adam

  18. US Army Camp Hospital, Aix-Les-Bains, France 1918

  19. Patients convalescing , 1918 Courtesy of the National Museum of Health and Medicine

  20. Lessons from past pandemics • Occurs unpredictably, not always in winter • Great variations in mortality, severity of illness and pattern of illness or age most severely affected • Rapid surge in number of cases over brief period of time, often measured in weeks • Tend to occur in waves - subsequent waves may be more or less severe Key lesson - unpredictability

  21. Virology

  22. Different types of flu viruses • Flu viruses are divided into three main groups: Influenza A, B and C • A viruses – source of ‘ordinary’ flu epidemics and all pandemics • A viruses also infect birds and other animals such as pigs and horses • B and C viruses infect humans only

  23. Influenza Types Hosts Type A Humans, birds, pigs and horses Type B Humans only Type C Humans only

  24. Change • Particular characteristic that enables influenza A viruses to cause annual epidemics, even pandemics • Type A viruses undergo frequent changes in their surface antigens or proteins • Minor changes - antigenic drift • Major changes - antigenic shift

  25. Antigenic drift • Occurs among influenza A viruses resulting in emergence of new variants of prevailing strains every year • New variants result in seasonal flu each winter • Some years are worse than others – partly related to degree of ‘drift’

  26. Antigenic shift • Major changes occur in the surface antigens of influenza A viruses • Occurs by mutation or by ‘re-assortment’ between viruses • Changes are more significant than those associated with antigenic drift • Changes lead to emergence of potentially pandemic strains by creating a virus that is markedly different from recently circulating strains

  27. Antigenic shift • Population will have little or no immunity to new virus: • - all or most people will not previously have had infection due to it • - will not have been vaccinated against it • Lack of immunity allows virus to spread more rapidly and more widely than ‘ordinary’ flu viruses

  28. Pandemic strainreassortment in pig Migratory water birds

  29. Pandemic StrainReassortment in humans Migratory water birds

  30. Avian influenza

  31. Avian influenza • Highly pathogenic avian flu (A/H5N1) currently circulating in poultry in Asia • Strain of Avian flu has shown ability to transmit from poultry to people • Fear that humans infected with Avian flu could also be infected with ‘ordinary’ flu • Exchange of genes could lead to emergence of a potentially pandemic strain

  32. Warning signs • Experts from WHO believe signs of another pandemic are increasing: • Continued outbreaks of Avian H5N1 infection in poultry in Southeast Asia • Linked to human cases of Avian H5N1 flu • Raised concern virus may be adapting to infect people more readily

  33. Pandemic flu effect on the UK • Impossible to predict when it will begin • Difficult to predict impact with any accuracy • Estimates of scale of illness, death rates and those most likely to have severe illness are uncertain • Will also depend on the availability and effectiveness of antiviral drugs and vaccines

  34. Impact on health services • Likely to place great pressure on health and social services • Increased numbers of patients requiring treatment • Depletion of the workforce due to illness and other disruption

  35. Impact on business • 25% of the UK workforce will take 5-8 working days off over a three-month period • Estimates suggest that during the peak absenteeism will double in the private sector and increase by two-thirds in the public sector

  36. Health Impact Assessment Base scenario • Cumulative clinical attack rate of 50% of the population over one or more waves, around 15 weeks each, weeks or months apart • ‘Worst case’ of single wave with 50% attack rate • Overall case fatality rate of 0.37% (based on inter-pandemic and 1957 experience) • Hospitalisation rate of 0.55% (based on inter-pandemic experience)

  37. Impact on schools and services • Likely to spread rapidly in schools and other closed communities • Impact on all services including police, fire, the military, fuel supply, food production, distribution and transport, prisons, education and business

  38. Pandemic waves (1) Past experience teaches us that following the emergence of a new pandemic virus: • more than one wave of influenza is likely • the gaps between the waves may be weeks or months • a subsequent wave could be worse than the first

  39. Seasonal and pandemic influenza: Weekly GP consultations for influenza-like illness

  40. Containing pandemic flu

  41. What an influenza pandemic will mean for the UK • High levels of illness • Intense pressure on health services • Disruption to many aspects of daily life • Many deaths

  42. Reduce impact through: • Surveillance • Diagnosis • Antiviral drugs • Vaccines (once they become available) • Public health interventions • Ensure Business Continuity

  43. Virological surveillance Year round global activity led by WHO, to: • Monitor the evolution of flu viruses • Inform recommendations for annual flu vaccine • Detect the emergence of new or unusual viruses

  44. Diagnosis • Most often a clinical diagnosis • Laboratory tests • molecular detection of virus in clinical specimens • culture of virus • serology

  45. Public health interventions • Personal interventions • Basic measures to reduce the spread of infection • Hand washing: washing hands frequently with soap and water reduces the spread of the virus from the hands to the face, or to others • Respiratory hygiene: covering the mouth and nose when coughing or sneezing; using a tissue when possible; disposing of dirty tissue promptly and carefully – bag and bin • Avoiding non essential travel: non attendance at large gatherings such as concerts, theatres, cinemas, sports arenas etc

  46. Possible population-wide interventions • Travel restrictions • Restrictions of mass public gatherings • Schools closure • Voluntary home isolation of cases • Voluntary quarantine of contacts of known cases • Screening of people entering UK ports

More Related