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January 19, 2006

Should we worry about bird flu?

With opinions mutating faster than the virus itself, experts are weighing their concerns about the avian flu. Could it be the next Y2K-type non-issue? Or will it be a repeat of the 1918 flu widely considered to be the world’s worst pandemic?

No one can say for certain.

The World Health Organization (WHO) has received reports of 148 laboratory-confirmed human cases of avian flu, 79 of them fatal, as of Jan. 14. Since 2003, cases have been reported in Cambodia, China, Indonesia, Thailand, Turkey and Viet Nam.

Infection typically is the result of contact with infected birds and WHO reports have stated there is no evidence of sustained human-to-human transmission of the virus. WHO officials continue to monitor virus-affected areas to watch for any indication of human-to-human transmission, a possible precursor to a widespread health crisis.

The world stands at level 3 on the WHO’s 6-level pandemic threat alert scale. A new virus subtype “is causing disease in humans, but is not yet spreading efficiently and sustainably among humans,” according to the WHO web site at www.who.int.

Samuel Stebbins, director of Pitt’s Center for Public Health Preparedness, said level 3 is like “standing on the diving board, just getting ready to go into the pool.”

The H5N1 avian flu virus has met two of three WHO criteria signaling a pandemic threat: A new flu virus subtype has emerged and it infects humans, causing serious illness. The third condition, that it spreads easily between humans, has not been met.

But each human infection increases the risk that the virus will mutate into a virulent variety that can be passed readily from human to human.

“The risk of widespread human infection is very real,” Stebbins said. “With any luck it will be limited to a region or a country,” or mutate into a form that doesn’t cause serious illness.

The extremely contagious nature of flu and its ability to mutate rapidly leave many questions unanswered. Will it mutate into a virulent form? Can it be contained? When and if is anyone’s guess, with experts disagreeing on whether H5N1 will fade away or cause global disruptions.

What is sure: The world is not prepared for a pandemic, the WHO cautions. Stebbins agrees. In a Jan. 9 lecture, co-sponsored by the Center for Public Health Preparedness and the Center for Public Health Practice, Stebbins warned that vaccine production and distribution processes are inadequate and public health advice on flu today — essentially to cover coughs and sneezes and follow good handwashing procedures — is not much more advanced than it was in 1918.

According to the WHO, no vaccine against the H5N1 virus is ready for commercial production, although several are under development. And, global production capacity is insufficient to meet worldwide need in case of a pandemic.

Antiviral medications, such as Tamiflu, may offer some benefit, but the virus could quickly become resistant, Stebbins said.

“No viral illness in a population has ever been controlled by medication,” he said.

Stebbins said the United States may be prepared for a short-term disruption, but not for one such as a flu pandemic that could last weeks or months.

“I don’t think we know how to conceptualize pandemic,” he said, adding that the effects of a pandemic should be viewed in terms of more than just numbers.

The 1918-1919 outbreak infected one-third of the world’s population and killed an estimated 50 million to 100 million people. If an outbreak of that magnitude hit the United States today, 90 million people would be infected and 2 million would die, Stebbins said.

The ripple effects of such an illness would be far-reaching, Stebbins said: Schools would close; medical services would be overtaxed; people would stay at home, causing restaurants, theatres and bars to close.

Basic services such as power, food, water, phones, mass transit, gasoline, schools and day care all could be interrupted. Lean business practices that leave razor-thin inventories on hand would quickly cause shortages if the supply chain were disrupted by widespread sickness and fears of infection.

In a worst-case scenario, the economic disruption would plunge the nation into a recession, according to a study released in December by the Congressional Budget Office (CBO).

The potential supply-side effect, due to reduced productivity among workers, could cut the Gross Domestic Product (GDP) by 5 percent, based on CBO worst-case estimates that 30 percent of workers in each sector would become ill and 2.5 percent of them would die.

Survivors would miss three weeks of work, because they were sick, home caring for sick family members, or home for fear of catching the flu.

Potential demand-side effects could steal another 2 percent of the GDP, with the CBO estimating an 80 percent decline in the entertainment, arts, recreation, lodging and restaurant industries as people avoided social contact or were too sick to go out.

The CBO estimated GDP would decline by 1.5 percent, or $160 billion (in 2004 dollars). “Compared to the long-run growth trend, a mild influenza pandemic would cause growth to slow, but would probably not cause real GDP to fall (or cause a recession,)” the study stated.

Psychological effects of a pandemic could be equally devastating.

Stebbins said there is a failure of imagination to conceive of all the possible issues surrounding a pandemic.

Stebbins pondered the psychological responses to a distant threat of flu, or to an outbreak nearby. Would people stay home? Go someplace they perceive to be safer? How would people respond to getting symptoms, becoming ill, or having a family member die? Or having multiple family members die?

Would people hole up at home and wait for a vaccine to become available? Would they hoard food and supplies, or perhaps defend their cache with weapons?

“We don’t know what we don’t know,” he said.

Unlike 1918 when a good portion of America’s population lived on farms and had their own food and fuel supplies, there is significantly more interconnection today.

Crowding and international travel have increased, as have the number of institutions such as jails, hospitals and nursing homes where the disease could spread rapidly in close quarters.

And the demographics of the population have changed: Overall, the population is older and there are more people (such as transplant patients or those with AIDS) who are immunosuppressed, and more with chronic illnesses, Stebbins said.

In addition, expectations today are higher. “We can fly someone to the moon; we should be able to protect ourselves from pandemic flu,” is the attitude, Stebbins said.

Federal and state health officials are urging preparation in case a pandemic occurs. The federal government advises individuals and families to store a supply of food, water, prescription and non-prescription medications in case a long stay at home is required. A checklist is available online at www.pandemicflu.gov.

Stebbins said most people have a “wait and see” attitude; he admits that even he has not squirreled away such supplies.

“In a broad sense, we are woefully unprepared,” he said, balancing his remark with confidence that Americans typically show an ability to respond quickly when necessary.

Stebbins said getting a consistent message out to people will be crucial in case of a pandemic or other crisis, noting that people tend to maintain their “wait and see” attitude, then overreact until they are reassured. Coordinating that message among various federal, state and local agencies and other sources of information will be vital, he said.

—Kimberly K. Barlow


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