Published in UAB Insight, Summer 2007

Will affect every aspect of society

An influenza pandemic is inevitable, but may not be imminent, says David O. Freedman, MD, professor of medicine in the UAB Division of Infectious Diseases. “We are due. A big pandemic occurs every 30 or so years, and the last major pandemic was in 1968,” he says. The H5N1 “bird flu” strain, which experts have been tracking for more than 3 years, may not acquire the property of efficient human-to-human transmission, but “another new strain eventually will emerge and mutate. Thorough advance planning positively correlates with lives saved,” Freedman says.

A mutated virus would circle the globe in waves over 12 to 18 months. Experts estimate a clinical disease attack rate of 30% or higher in the overall population, as humans will have no immunity to a mutated strain. Vaccine development will lag by months, and the current antiviral medication supply is insufficient. Using a worst-case scenario based on the 1918 pandemic, the United States would need 191% of existing hospital beds, 461% of intensive care unit beds, and 198% of ventilators to meet demand. The virus would circulate for 6 to 8 weeks in each community, with an absenteeism rate of 40%, causing a critical shortage of health care and other workers, school and business closings, the interruption of basic services, and economic loss. As many as 2 million Americans may die, according to the US Department of Health and Human Services (HHS).

In April the US Food and Drug Administration issued its first approval for a human vaccine against H5N1. Developing a new vaccine against a previously unknown strain requires a minimum of 3 months, and a new influenza strain will require two doses given a month apart to immunize each person. Furthermore, “antiquated chicken egg-based vaccine technology hinders our ability to produce mass quantities of vaccine,” Freedman says. Scientists continue to study cell-based vaccines using a variety of viral expression systems. Such vaccines, usually based on mammalian kidney cells, can potentially meet surge capacity needs and promise to be more reliable, flexible, and expandable than egg-based versions. “This technology is still experimental, and its safety and efficacy have yet to be determined,” he says.

“The antivirals oseltamivir (Tamiflu) and zanamavir (Relenza) are very effective against H5N1 and other flu strains in the lab, but there is insufficient data in patients infected with H5N1,” Freedman says. The federal government’s National Strategy for Pandemic Influenza requires stockpiling of supplies (such as hospital cots, masks, and ventilators) and antivirals, but the government has collected only a quarter of the doses needed to treat the US population. “A mutated influenza strain will have a different drug sensitivity pattern and may require twice the dose for twice as long to be effective,” Freedman says. Health care and medication plant workers will be priority groups, but “beyond that, deciding who gets an antiviral may be chaotic.”

Federal Preparedness Strategies
HHS is the centralized authority for implementing the government’s plan, which aims to slow pandemic influenza entry into the United States and limit domestic spread; mitigate disease, suffering, and death; and sustain economic infrastructure. Specific federal efforts, although not yet fully funded, include new initiatives for rapid development of vaccines, drugs, and adjuvants, which may reduce the amount of vaccine necessary; adapting existing egg-based vaccine facilities to pandemic vaccine production; development of diagnostic testing that allows swift recognition of a pandemic virus in the human population; and building international infrastructures that rapidly recognize and respond to an outbreak of a pandemic virus.

For more than a decade the Global Travel/Tropical Disease Surveillance Network (GeoSentinel), part of the International Society of Travel Medicine (ISTM) and the Centers for Disease Control and Prevention (CDC), has monitored emerging infections of potential global impact at their point of entry into domestic populations. GeoSentinal allows early detection of influenza outbreaks with potential to spark a pandemic. Freedman developed the initial project with colleagues at Emory University and the CDC. Thirty-eight GeoSentinel sites and 145 ISTM clinics on six continents collect data on disease risks and outbreaks to educate and keep travelers healthy, determine geographical patterns of disease, and disseminate alerts to affected communities or government entities. “We know the normal incidence for respiratory cases. If the number jumps suddenly, that bears careful surveillance,” he says.

Freedman, who also directs the UAB Travelers’ Health Clinic, encourages vaccination for those visiting tropical countries and other areas where influenza may be active. The clinic, which offers pre- and post-trip consultation with a specialist physician, offers influenza vaccine year-round as it is always influenza season somewhere.

State, County, and City Planning
HHS directs each state, county, city, and organization to create their own strategies and procedures, all scaffolding on each other. Local governments are responsible for building partnerships with health care facilities and community leaders and developing communications infrastructures for timely dissemination of information.

The Alabama Department of Public Health’s (ADPH) Center for Emergency Preparedness developed a multitiered strategy that delineates responsibilities at all levels of society. The department is working to ensure viability of government functions and services such as energy, financial services, transportation, telecommunications, firefighting, and public safety. ADPH is assisting businesses and utilities with continuity of operations plans, collaborating with the health care sector on issues such as stockpiles, available beds, isolation and quarantine plans, surge capacity, personal protection, communications links during crisis, and pharmaceutical supply and distribution. ADPH is stocking basic medical supplies, masks, and antivirals. The department aims to coordinate offsite treatment and triage locations and medical stations and is implementing a mass fatality management plan.

Forecasted Impact of Moderate And Severe Pandemic Influenza Scenarios

Characteristic	Moderate (Like 1958/1968 pandemic) US data based on population	Severe (Like 1918 pandemic) US data based on population
Illness	90 million (30%)	90 million (30%)
Outpatient medical care	45 million (50%)	45 million (50%)
Hospitalization	865,000	9,900,000
ICU care	128,750	1,485,000
Mechanical ventilation	64,875	745,500
Deaths	209,000	1,903,000
Alabama Data Based On Population
Illness	1,350,000	1,350,000
Outpatient medical care	675,000	675,000
Hospitalization	12,975	148,500
ICU care	1931	22,275
Mechanical ventilation	973	11,183
Deaths	3135	28,545
Estimates are based on past pandemics in the United States and do not include the potential impact of interventions not available during the 20th century pandemics. Alabama’s population (4,486,508) represents 1.5% of the total US population (295,734,134).

“A top priority is educating families and organizations about community-based interventions that can stop or limit the spread of disease in the state,” says Cynthia Lesinger, ADPH pandemic influenza coordinator. Families need to teach social distancing behaviors and cough etiquette, plan how they will care for themselves if they become sick, stockpile necessary drugs and fever and pain reducers, and more.

“Physicians in private practice need established procedures for continuous operations in the face of up to 40% absenteeism and should disseminate information for self-care in case patients cannot access providers,” says Alabama State Health Officer Donald E. Williamson, MD. Fact sheets and planning checklists are available at adph.org/pandemicflu.

HHS specifically has directed health care facilities to create response structures, disease surveillance methods, triage and clinic plans, and mortuary strategies. UAB Hospital will rely on its established Airborne Pathogens Exposure Control Plan in addition to ongoing recommendations from the university’s Pandemic Influenza Task Force. Plans for the hospital include stockpiling masks, obtaining more ventilators, designating potential intensive care unit isolation areas and general patient care areas, and cooperating with the Jefferson County Department of Health on dissemination of antivirals and vaccines. UAB Hospital continues to refine its tactics for continued operations with reduced staff.

“Continuing to build infrastructure to absorb rapid surge capacity at all levels and developing vaccine and drug technology will enable health care providers to save as many lives as possible,” Freedman says.

For more information:
Dr. David Freedman
1.800.UAB.MIST
mist@uabmc.edu