Pandemic Influenza: Pandemic Influenza: the “Mother of All Disasters”? October 11, 2007 Healthy Carolinians Annual Conference Steve Cline, DDS, MPH NC Division of Public Health

Objectives Review the fundamentals of pandemic influenza Assess the current threat of pandemic influenza Review influenza surveillance – How will we know? Discuss pandemic influenza preparedness and response in North Carolina

Types of Influenza Viruses Influenza A –epidemic or pandemic –animals and humans –differing pathogenicities –divided into subtypes based on surface proteins (H & N) 144 combinations constantly mutate variation within subtype Influenza B –epidemic –humans (primarily) –not divided into subtypes Influenza C –humans –mild respiratory illness

Seasonal Flu: Signs and Symptoms FeverHeadache Muscle aches Extreme fatigue Dry cough Sore throat Runny or stuffy nose happycarpenter.blogs.com

Flu Fundamentals: Respiratory Spread Transmission: Respiratory droplets –Each infected person infects 2-3 others Incubation period: 1 to 5 days from exposure to onset of symptoms Communicability: –1-2 days before symptom onset –4-5 days after onset Timing: Peak usually occurs December through March in North America

Deaths 25, ,000 Hospitalizations 114, ,500 Infections and illnesses million Physician visits ~ 25 million Thompson WW et al. JAMA. 2003;289: Couch RB. Ann Intern Med. 2000;133: Patriarca PA. JAMA. 1999;282:75-7. ACIP. MMWR. 2004;53(RR06):1-40. Seasonal Influenza Impact NC and US Society NC NC NC 730,000 NC 1.7 million

Pandemic Influenza Major mutation occurs –Genetic reassortment of human and avian influenza viruses –Direct animal (poultry) to human transmission Results in new subtype of influenza A –Avian origin –Adapted to humans –No immunity in the human population Results in multiple simultaneous epidemics worldwide with enormous numbers of deaths and illness –Six to eight weeks –Multiple waves

Pandemics of the 20 th Century YearSubtype Impact in the United States Spanish flu H1N1 550,000 deaths Asian flu H2N2 69,800 deaths Hong Kong flu H3N2 33,800 deaths

“Pandemic Watch”

Avian Influenza Water birds are the natural reservoir –Carry virus in intestines –Virus shed in feces and respiratory secretions –Usually do not get sick Highly contagious among birds Most of no human health significance

Pandemic “Prerequisites” Novel virus emerges Novel virus causes disease in humans Novel virus can be efficiently transmitted person to person Dr. Asamoa-Baah, Assistant Director General, WHO Communicable Diseases

WHO Pandemic Phases

H5N1 in Humans Current outbreak began December 2003 Initially cases were limited to Southeast Asia Geographic distribution continuing to expand in 2006 –Human cases are now being reported in Europe and Africa

Global Migration of H5N1 October 5, 2007

Backyard flocks

Direct Contact with Poultry Primary Risk Factor Plucking and preparing diseased poultry Handling fighting cocks Playing with poultry Consumption of duck’s blood or possibly undercooked poultry

“Pandemic Watch” Global Perspective Good news –No evidence of sustained person-to-person transmission –Recent human cluster in Indonesia not a major genetic shift Bad news –H5N1 virus continues to circulate widely in Asia, Europe and Africa –Eradication of H5N1 in birds is difficult

“Pandemic Watch” United States No reported cases of H5N1 –Migratory birds –Poultry –Humans Other avian influenza viruses detected in poultry in 2004 –H5N2 in Texas –H7N2 in Maryland

Impact of an Influenza Pandemic North Carolina Planning Assumptions 1.4 million outpatient visits 29,000 hospitalizations 6,700 deaths Assuming 30% attack rate and NC population of 8.5 million people Based on CDC software FluAid 2.0

Pandemic Influenza Planning Goals –Reduce morbidity –Reduce mortality –Reduce social disruption

Pandemic Influenza Planning Challenges –Widespread –Long duration –Health services overwhelmed –Shortages may occur MedicationsEquipment Hospital beds Personnel

Pandemic Preparedness Activities NC Pandemic Influenza Response Plan Exercises –Eight tabletop exercises Jan-Feb 2006 –Statewide full scale exercise May 2006 –Total of 185 pan flu exercises Pandemic Influenza Ethics Task Force Federal Supplemental Funding

North Carolina Pandemic Influenza Response Plan Collaboration among many different groups First version posted to website October 2004 Modeled after other plans –National Planning Guide (CDC) –NC SARS Response Plan Revised version completed January 2006 Pandemic COOP May 2007

Core Components NC Pandemic Plan Command and Control Surveillance Vaccine Preparedness and Response Antiviral Preparedness and Response Medical Surge Preparedness in Healthcare Facilities Communication

Appendices NC Pandemic Plan Supplements to core parts of plan “Stand alone” appendices –Laboratory diagnosis –Community containment –International travel guidelines –Mass fatality plan –Legal issues –Mental health

Local Health Department Toolkit NC Pandemic Plan Roles by pandemic phase Determination of county-level impact Influenza vaccine estimation Designation of alternate care sites Collaborations with local partners Emergency Plans for Vulnerable Populations

Goals of Community Mitigation in a Pandemic 1.Delay and flatten outbreak peak 2.Reduce peak burden on healthcare infrastructure 3.Reduce number of cases 4.Buy time Daily Cases #1 #2 #3 Days since First Case No intervention With interventions

Community Mitigation of Influenza: Epidemiologic Data School closure helpful in flu outbreak, Israel –Significant decreases in children’s diagnoses of respiratory infections (42%), visits to physicians (28%), emergency departments (28%), and medication purchases (35%). Flu immunizaton of schoolchildren associated with lower population illness rates –Controlled trial, small towns in Michigan, –Immunization of children in Japan, Lower rates of isolation of influenza and other respiratory viruses in Hong Kong in SARS –Many social distancing measures, public mask use Reference: WHO Writing Group. Emerg Inf Dis 2006;12:81-7

Community Mitigation of Influenza: Historical Information from 1918 Forced isolation, quarantine, social distancing, masks, travel restrictions seemed ineffective in 1918, but unclear if partially effective –WHO Writing Group. Emerg Inf Dis 2006;12:88-94 Recent hypothesis: Varying death rates in US cities may have been due to differential implementation of mitigation measures –Further historical study in progress –Markel H, Univ. of Michigan

Weekly mortality data provided by Marc Lipsitch (personal communication)

Summary: Community Mitigation of Pandemic Influenza, TLC Home isolation of ill patients not needing hospitalization Voluntary home quarantine for household contacts Social distancing measures –School closure and protective sequestration of children may have profound impact –Workplace COOP (liberal leave vs. closure) –Limit public gatherings Personal infection control measures –Hand hygiene and cough etiquette –Mask use for ill persons Disinfection of contaminated surfaces Antivirals for treatment & targeted prophylaxis

Pandemic Influenza Planning Ongoing Issues Strengthen local health department plans Exercise pandemic influenza plans Increase situational awareness outside of public health Encourage planning among other entities –Businesses –Schools –Volunteer organizations (Vulnerable Populations)

Online Resources

Conclusions Forecasting the next pandemic is difficult Current outbreaks of H5N1 pose an ongoing threat Pandemic influenza presents unique challenges for planners Many different entities need to plan Everyone has a role

Prevention and Planning It Begins At Home The more you prepare yourself and your family, the more likely you can fulfill roles in an emergency

Questions? Thank you Steve Cline, DDS,MPH Deputy State Health Director NC Division of Public Health