Seasonal, Avian, and Pandemic Influenza TOP

Slide 1: Seasonal, Avian, and Pandemic Influenza Niranjan Bhat, MD Influenza Branch Division of Viral and Rickettsial Diseases National Center for Infectious Diseases Centers for Disease Control and Prevention

Seasonal, Avian, and Pandemic Influenza TOP

Slide 2: Impact of Influenza An annual public health problem Substantial health impact 10-35% of children each year 5-20% of adults each year Substantial economic impact Lost work / school days Overwhelmed medical care systems "A singular global infectious disease threat"

Seasonal, Avian, and Pandemic Influenza TOP

Slide 3: What is Influenza? The flu" = acute febrile respiratory illness Caused by infection with an influenza virus Classically Fever (≥100.0 F) plus cough or sore throat "Influenza-like Illness" ("ILI")

Seasonal, Avian, and Pandemic Influenza TOP

Slide 4: Other Features Headache, fatigue, body aches Range of symptoms differ by age Vomiting and diarrhea in children Fever alone in infants Often confused with other illnesses "Viral illness" "Cold" "Stomach flu"

Seasonal, Avian, and Pandemic Influenza TOP

Slide 5: Transmission Highly contagious Primarily person-to-person Incubation period: 1-4 days Subclinical infection can occur

Seasonal, Avian, and Pandemic Influenza TOP

Slide 6: Transmission Infectious period May begin 1 day before symptom onset Peak viral shedding on day 1 of symptoms Adults shed for 4-6 days Infants and children may shed longer Immunocompromised patients can shed for months

Seasonal, Avian, and Pandemic Influenza TOP

Slide 7: Influenza Morbidity and Mortality Annual average of >200,000 influenza-related hospitalizations 36,000 influenza-related deaths High rates in persons with chronic high-risk conditions in all age groups Children: Highest rates in young children <2 years Children 2-5 years next highest Adults: Highest rates in persons 65 years

Seasonal, Avian, and Pandemic Influenza TOP

Slide 8: Influenza Vaccination Recommendations of the Advisory Committee on Immunization Practices (ACIP) Persons aged: ≥65 years 6-59 months 50-64 years All high-risk persons ≥6 months of age Household contacts of high risk persons and health care workers

Seasonal, Avian, and Pandemic Influenza TOP

Slide 9: Influenza Antiviral Drugs Treatment 5 day course Should be started <48 hours from illness onset Shown to reduce symptoms by approximately 1 day Reduces viral shedding Chemoprophylaxis 70 - 90% effective in preventing illness from influenza Infection may still occur Examples: For control of nosocomial outbreaks For patients who cannot receive vaccine

Seasonal, Avian, and Pandemic Influenza TOP

Slide 10: Influenza Antiviral Drugs Amantadine, rimantadine Influenza A only Not currently recommended due to high frequency of resistance in circulating strains   Oseltamivir, zanamivir Influenza A and B Approved ages vary by drug and indication No treatment or prophylaxis approved for children aged <1 year

Seasonal, Avian, and Pandemic Influenza TOP

Slide 11: Influenza Testing Viral culture (gold standard) Serology (requires paired samples) Immunofluorescence (IFA, DFA) Reverse-transcriptase polymerase chain reaction Rapid diagnostic testing Specimens: nasopharyngeal swab is ideal Also, nasal swab, NP or nasal aspirate Best if close to illness onset (<4 days) Optimal specimen site can differ for non-human influenza viruses

Seasonal, Avian, and Pandemic Influenza TOP

Slide 12: Influenza Viruses Illness caused by infection with an influenza virus Primarily infects the upper respiratory tract Negative single-stranded RNA virus 8 gene segments code for 10 proteins Influenza viruses classified into types A, B, and C Image: Illustration of a Flu Virus

Seasonal, Avian, and Pandemic Influenza TOP

Slide 13: Influenza A Viruses Influenza A viruses further categorized by subtype Subtypes are determined by two surface glycoproteins Hemagglutinin (HA) Site of attachment to host cell surface receptors Antibody to HA is protective Neuraminidase (NA) Takes part in the release of virions from the cell

Seasonal, Avian, and Pandemic Influenza TOP

Slide 14: Influenza A HA and NA Subtypes Image: A Chart of Viral Subtypes and the Species Affected

Seasonal, Avian, and Pandemic Influenza TOP

Slide 15: Avian and Human Influenza A viruses Avian Influenza A Viruses H1 - H16 N1 - N9 Image: A duck Human Influenza A Viruses H1 - H3 N1 - N2 Image: A human family

Seasonal, Avian, and Pandemic Influenza TOP

Slide 16: Antigenic “drift” Minor antigenic changes to the hemagglutinin protein Continuous process Allows escape from population immunity Can lead to a new replacement strain for a particular subtype Antigenic drift leads to seasonal epidemics Vaccine strains must be updated each year Two type A strains (H1N1, H3N2), one type B strain

Seasonal, Avian, and Pandemic Influenza TOP

Slide 17: Antigenic “shift” Emergence of a novel human influenza A subtype: Direct bird-to-human transmission Through adaptation to a human host>br> or Genetic reassortment between human and animal influenza viruses Co-infection within a human host Co-infection within an intermediate host (eg, swine)

Seasonal, Avian, and Pandemic Influenza TOP

Slide 18: Direct Infection Image: Avian Reservoir to Direct Avian Human Infection to Human Virus

Seasonal, Avian, and Pandemic Influenza TOP

Slide 19: Reassortmentof Influenza A Viruses Image: Avian Reservoir to Other Animals to new Reassorted Virus to Human Virus

Seasonal, Avian, and Pandemic Influenza TOP

Slide 20: Influenza Pandemics Requirements: Emergence of a novel human influenza A subtype (antigenic shift) AND Efficient human-to-human transmission Causes significant human disease A pandemic can result in: Increased overall morbidity and mortality Higher proportion of deaths in younger adults

Seasonal, Avian, and Pandemic Influenza TOP

Slide 21: Impact of Influenza Pandemics 1918-19 Spanish Flu (H1N1) 20-50 million deaths worldwide >500,000 U.S. deaths 1957-58 Asian Flu (H2N2) 70,000 U.S. deaths 1968-69 Hong Kong Flu (H3N2) 34,000 U.S. deaths

Seasonal, Avian, and Pandemic Influenza TOP

Slide 22: Estimated Impact of a Future Influenza Pandemic in the U.S. Deaths 89,000-207,000 Hospitalizations 314,000 - 734,000 Outpatient visits 18 - 42 million Additional illnesses 20 - 47 million Economic impact $71.3 - 166.5 billion Population affected 15-35% (U.S. population: 290 million)

Seasonal, Avian, and Pandemic Influenza TOP

Slide 23: Pandemic Influenza Compared with avian influenza A(H5N1) Clinical features Diagnosis Treatment Prevention Control

Seasonal, Avian, and Pandemic Influenza TOP

Slide 24: HHS Pandemic Influenza Plan Supports the National Strategy for Pandemic Influenza Outlines planning assumptions and doctrine for health sector pandemic preparedness and response Public Health Guidance for State and Local Partners 11 Supplements with detailed guidance www.pandemicflu.gov

Seasonal, Avian, and Pandemic Influenza TOP

Slide 25: Pandemic Plan Objectives Prevent or at least delay introduction into the United States May involve travel advisories, exit or entry screening For first cases, may involve isolation / short-term quarantine of arriving passengers

Seasonal, Avian, and Pandemic Influenza TOP

Slide 26: Pandemic Plan Objectives Slow spread, decrease illness and death, buy time Antiviral treatment and isolation for people with illness Quarantine for those exposed Social distancing Vaccine when available Local decisions

Seasonal, Avian, and Pandemic Influenza TOP

Slide 27: Pandemic Plan Objectives Clearly communicate to the public Prepare people with information Encourage action steps to prepare now Provide updates when new information emerges Use trusted messengers Coordinate to ensure consistent messages Address rumors and inaccuracies

Seasonal, Avian, and Pandemic Influenza TOP

Slide 28: Pandemic Vaccine Expand production of current vaccine Evaluate dose-sparing technology Accelerate development of modern (non-egg) vaccines Target new antigens

Seasonal, Avian, and Pandemic Influenza TOP

Slide 29: Antivirals Stockpile Oseltamivir (Tamiflu) Zanamivir (Relenza) Goal: quantity to treat 25% of the U.S. population Distribution? Strategy Initial containment Treatment Prioritization – science and values, public engagement Preserve societal functioning Protect those most at risk New antiviral candidates

Seasonal, Avian, and Pandemic Influenza TOP

Slide 30: Funding $350 million for state and local response capacity $100 million has been awarded to All 50 states 7 territories; Puerto Rico; Washington, DC; New York City; Chicago; Los Angeles County Allocated according to a base + population formula $250 million to be awarded later this year

Seasonal, Avian, and Pandemic Influenza TOP

Slide 31: Network of Responsibilities Local - state - federal Domestic – international Public – private Multi-sector Non-partisan Animal – human Health protection – homeland security – economic protection www.pandemicflu.gov

Seasonal, Avian, and Pandemic Influenza TOP

Slide 32: Pandemic Influenza Checklists State and Local Business Preschool Schools (K-12) Colleges & Universities Faith-based & Community Organizations Travel Industry Physician Offices and Ambulatory Care Home Health Emergency Medical Services

Seasonal, Avian, and Pandemic Influenza TOP

Slide 33: State and Local Public Health Community Leadership and Networking Surveillance Health System Partnerships Infection Control and Clinical Care Vaccine Distribution and Use Antiviral Drug Distribution and Use Community Disease Control and Prevention Communications Workforce Support

Seasonal, Avian, and Pandemic Influenza TOP

Slide 34: Medical Offices and Clinics Start a planning committee Develop a plan Surveillance and detection Communication - With public health, other facilities, staff, patients Education and training Triage, management, infection control Occupational health and surge capacity Antiviral and vaccine planning

Seasonal, Avian, and Pandemic Influenza TOP

Slide 35: Individuals Store a supply of water and food Have nonprescription drugs and other health supplies on hand Pain relievers, stomach remedies, cough and cold medicines, fluids with electrolytes, vitamins Talk about what will be needed to care for family members in the home Get involved in the community; volunteer with local groups to prepare

Seasonal, Avian, and Pandemic Influenza TOP

Slide 36: Future Directions More detailed guidance Universal preparedness Exercises Integration Updates and Adaptation “Preparedness, not panic” “Inform, not inflame”

Seasonal, Avian, and Pandemic Influenza TOP

Slide 37: Seasonal, Avian, and Pandemic Influenza Seasonal influenza viruses A public health problem every year Circulate throughout the human population Spread easily from person to person Avian influenza A (H5N1) Devastating global outbreak in poultry Rare but severe human infections Does not spread easily from person to person Pandemic influenza viruses Appears in the human population periodically H5N1 is a likely candidate, but is not a pandemic virus yet

Seasonal, Avian, and Pandemic Influenza TOP

Slide 38: Note Please be aware that the findings, opinions, and conclusions in these presentations represent the state of our knowledge as of March 29, 2006, and that information regarding avian influenza will likely change over time. In addition, some recommendations presented here may become inconsistent with the rapidly evolving policies and approaches of CDC or other U.S. government agencies. Finally, the findings and conclusions in these presentations have not been formally disseminated, and should not be construed to represent any agency determination or policy. Please contact Influenza Branch personnel for the most current information regarding avian influenza A (H5N1).

Seasonal, Avian, and Pandemic Influenza TOP

Slide 39: Thank You Questions? Other resources: pandemicflu.gov/ www.cdc.gov/flu/avian/index.htm www.cdc.gov/flu/ www.usda.gov/ www.who.int/csr/disease/avian_influenza/en/ www.who.int/csr/disease/influenza/en/