Protecting the Community: The Science of Pandemic Flu What’s the difference? • Seasonal “Human” Flu • Pandemic Flu • Avian Flu • Putting it all together A Look at the Influenza Virus What is Seasonal Influenza? Influenza (flu): • Highly infectious viral disease caused by various types of influenza viral strains • Characterized by mild to severe respiratory illness • Vaccine is available and must be updated each year How Flu Spreads • Influenza virus is easily spread, usually by airborne droplets that reach the eyes, nose or mouth- inhalational exposure/ muscosal exposure – Coughing – Sneezing – Singing How Flu Spreads • People can also be infected by touching something (fomite) with flu viruses on it and then touching their mouth or nose How Flu Spreads • Host factors: emission rates, concentration, susceptibility • Pathogen factors: duration of infectivity, infectious dose, size pf particles • Environmental factors: temperature, humidity, sunlight, air circulation How Flu Spreads • Evidence very limited on proportional contributions of different modes of transmission- may vary by strain How Flu Spreads • Transmission can occur 1 day before symptoms develop and up to 5 days after becoming sick The Burden of Seasonal Influenza • Globally: 250,000 to 500,000 deaths each year • In the United States each year: – 5% to 20% of the population gets the flu – 36,000 deaths (8th leading cause of death) – >200,000 hospitalizations – $37.5 billion in economic costs from influenza and pneumonia What is Pandemic Flu? • Flu pandemics are global epidemics of a newly emerged strain of flu (a new influenza A virus subtype) A Pandemic is a Perfect Storm* • A new flu virus is introduced into the human population– one for which immunity does not exist. • The virus must be capable of causing severe human illness. • The virus must be able to spread efficiently – through coughing, sneezing or a handshake. History of Influenza Pandemics The past is prologue . . . Influenza Pandemics 20th Century What is Avian Flu? • Avian flu, or bird flu, refers to influenza virus strains that primarily affect birds • All known subtypes of influenza A viruses circulate among wild birds • Wild waterfowl and shore birds are natural carriers (hosts) of avian flu viruses but rarely get sick • Domestic poultry can get very sick and die from some strains of avian flu Nations With Confirmed Cases H5N1 Avian Influenza (July 7) WHO Pandemic Phases Objectives for Pandemic Influenza Preparedness • Limit sickness and death • Maintain continuity of essential services • Minimize social disruption • Minimize economic losses Planning Assumptions for a Pandemic • Illness will spread quickly and globally • Illness will roll across a country in multiple waves, each wave actively affecting a community for 6 to 8 weeks at a time • Infection rate in population will be 30% or more; everyone will be susceptible • In a severe pandemic, work absenteeism may reach 40% during height of outbreak Planning Assumptions for a Pandemic • Vaccine will be non-existent or very limited for at least 6 months • The health care delivery system will be overwhelmed; shortages of staff, beds, supplies • Schools and daycares may be closed • Significant disruptions of critical infrastructure and social services may occur • Temporary shortages of food and water may occur Public Health’s Role • Disease surveillance and monitoring • Risk communication • Promotion of infection control measures: – Isolation/quarantine – Coordination of social distancing – Promotion of respiratory hygiene • Clinical interventions: Vaccine/ antiviral distribution (if available) Infection Control: Isolation and Quarantine • Isolation may have limited effectiveness in very specific situations including at the beginning of a community’s exposure to a novel influenza virus • Quarantine may be effective when appropriately implemented • Hospitals/Schools: Cohorting ill persons/workers Infection Control: Social Distancing • Social distancing- assuming large droplet transmission – School, day care closures – Banning of large social gatherings – Altering work place staffing rules to minimize number of people in common areas at same time – Alternate plans for distribution of critical supplies Infection Control: Hand Hygiene • Although extent of contribution of “autoinnoculation” is unknown, frequent, thorough hand washing is recommended • Alcohol based hand rubs are effective in decreasing risk • Appropriate hand hygiene also decreases risk to the environment Infection Control: Respiratory Hygiene • Cover mouth and nose when coughing, preferably in disposable tissues • Wash hands immediately • Use arm (v. hands) if no accessibility to hand washing, EtOH gels Infection Control: Barrier Precautions • Gowns, gloves, goggles • Masks: – Surgical masks: Designed to prevent ill person from disseminating disease- may be effective against large droplet transmission, may decrease risk of auto-innoculation – Respirators: Designed to prevent well person from inhaling small particles. Recommended for health care providers with close contact with ill individuals Clinical Interventions • Vaccine: – Recommend annual seasonal flu shot – Ongoing clinical trials – Investment in vaccine production infrastructure – Must assume delay in production and distribution Clinical Interventions • Antivirals (Oseltamivir and Zanavir): – May be effective if given very early – Must assume concerns with supply in a pandemic – Must consider possibility of drug resistance Public Health Preparedness: A Shared Responsibility! • Local – state – federal • Domestic – international • Public – private • Individuals • Animal – human • Health protection – homeland security – economic protection Encourage Healthy Habits • Encourage staff to get seasonal flu shots • Promote respiratory and hand hygiene – Lesson plans and educational posters – Stock up - ensure adequate availability of tissues, alcohol-based hand gel, soap, cleaning supplies • Key Messages: – Wash hands frequently with soap and water – Cover coughs and sneezes with tissue – Stay home from school when you are sick – Don’t share food Acknowledgements • CDC • NYSDOH • Seattle/King County Health Department Questions