What does an influenza virus look like? Hemagglutinin protein –Allows virus to stick to cells –Determines cell and species specificity Neuraminidase protein –Releases new virus particles from cells Genetic material divided into 8 separate segments Fig.1 Electron micrograph Fig.2 Schematic of influenza virus
Three Different Kinds of Influenza Seasonal Influenza “The Flu” Seasonal Influenza “The Flu” Avian Influenza “Bird Flu” Avian Influenza “Bird Flu” Pandemic Influenza “A Pandemic” Pandemic Influenza “A Pandemic”
Why does a pandemic occur? Antigenic shift Sudden change in antigenic structure of microorganisms, especially viruses, which produces new strains of the microorganism; hosts previously exposed to other strains have little or no acquired immunity to the new strain. “Novel Influenza A (H1N1)”
What is required for a pandemic of influenza to occur? Novel virus to which population has little or no immunity Virus that is pathogenic and virulent in humans Virus must be capable of sustained person-to-person transmission
A pandemic will result in larger numbers of all types of cases than in seasonal flu. The proportions of types of cases in a pandemic will depend on the severity of the pandemic.
How does the virus spread? Pigs? (why is it called “swine flu”) Airplanes? (yes, but…)
New WHO Phases of Pandemic Alert Phase 6 = Sustained community transmission of a new flu virus in 2 or more WHO regions. “Designation of this phase will indicate that a global pandemic is under way.” (www.who.int/csr/disease/avian_influenza/phase/en/index.html - See notes below)www.who.int/csr/disease/avian_influenza/phase/en/index.html
Reason #3: Pandemics have happened before; one is happening now. They can be severe. They are always important.
What were past flu pandemics like? 1918: “Spanish Flu” 1957: “Asian Flu”1968: “Hong Kong Flu” 20-40 million deaths 675,000 US deaths 1-4 million deaths 70,000 US deaths 1-4 million deaths 34,000 US deaths Credi: US National Museum of Health and Medicine
Reason #2: The humanitarian consequences of a pandemic could be devastating in terms of lives lost, economic disaster, and societal upheaval.
Reason #1: More than ever before, we can save lives during a pandemic!
H2P – Humanitarian Pandemic Preparedness and Response To limit excess mortality during a pandemic
New Tools for Intervention during a Pandemic Non-pharmaceutical (community mitigation) measures Strain-specific influenza vaccine Antiviral drugs (Tamiflu, Relenza) Antibiotics Infection control measures
Community Mitigation Isolation of those ill Voluntary quarantine of household members Social distancing of children (close schools?) Social distancing of adults (stagger working hours, close places of employment, places of worship, places of amusement) – those ill should stay home
Days Since First Case Daily Cases Pandemic Outbreak: No Intervention Pandemic Outbreak: With Intervention Delay outbreak peak Decompress peak burden on hospitals/infrastructure Diminish overall cases and health impacts 2 1 3
WHO/IFRC/UNOCHA/UNICEF “Call to Action” 1.Identify populations at increased risk of disease and death -- health care workers and other critical personnel -- pregnant women -- children -- underlying illness -- poor access to health care
WHO/IFRC/UNOCHA/UNICEF “Call to Action” 2.Reduce death by treating acute respiratory illness and pneumonia -- train, supervise and ensure health care workers, including CHWs, can identify, classify and treat acute lower respiratory illnesses -- plan for a 30% buffer stock of antibiotics, O 2, etc. -- educate communities about home-care, when to seek care outside the home, and when anti-virals are appropriate
WHO/IFRC/UNOCHA/UNICEF “Call to Action” 3.Reduce spread of disease -- prepare and disseminate risk communication messages -- map and train social mobilization networks to promote prevention -- identify target groups to receive first doses of vaccination and advocate for their access -- develop operational plans for mass vaccination
Current Knowledge Regarding H1N1 Vaccine A single dose of non-adjuvanted vaccine induces an immunogenic response in healthy young and middle-aged adults More people can be vaccinated with a fixed amount of vaccine Antibody responses will develop more rapidly than with two doses Vaccination campaigns will be easier to conduct
Current Knowledge Regarding H1N1 Vaccine Many countries have not developed plans for use of H1N1 vaccines: -- high-priority groups -- cold chain requirements -- points of distribution and delivery -- post-vaccination surveillance
WHO/IFRC/UNOCHA/UNICEF “Call to Action” 4.Continue critical services and plan for the worst -- review or create business continuity plans -- prioritize continuation of critical health and other essential services as part of a whole of society approach; build on existing multi-hazard, multi-sector plans -- ensure 8-12 weeks of buffer stocks of essential medicines to continue treating priority conditions
WHO/IFRC/UNOCHA/UNICEF “Call to Action” 5.Plan and coordinate efforts -- incorporate pandemic activities into existing coordination mechanisms -- recognize that no one agency can provide all of the priority interventions. Build on capacities and comparative advantages of each partner -- do not allow “lack of coordination” to become a cause of death