Preparing to Combat a Deadly Influenza Pandemic
“It is horrible. One can stand it to see one, two or 20 men die, but to see these poor devils dropping like flies sort of gets on your nerves. We have been averaging about 100 deaths per day, and still keeping it up. There is no doubt in my mind that there is a new infection here, but what I don’t know.”
Those words do not belong to a science fiction story. They come from a letter written in 1918 by a doctor in Camp Devens, Mass.
The killer was the influenza virus. It would spread in a matter of months and take the lives of more than 20 million people around the world--more than World War I would claim.
And it would strike again.
Two more global epidemics, or pandemics, of influenza started in Asia in 1957 and 1968, causing millions of deaths worldwide, including about 100,000 in the United States. In fact, some experts say that evidence of influenza pandemics taking place every few decades can be tracked down to at least the 1700s.
Such regularity, many believe, is an omen of the inevitable return of another pandemic. So certain are they of a comeback that researchers such as biologist Ann Reid of the Armed Forces Institute of Pathology refer to the present as an inter-pandemic period.
The question, say Reid and many of her colleagues, is whether countries are prepared for the day when the intermission is over.
If a pandemic hit today, between 89,000 and 207,000 Americans would probably die, with economic losses amounting to more than $70 billion, according to estimates from the Centers for Disease Control and Prevention.
But the threat of a pandemic seems distant and unreal, perhaps because the public associates influenza with a bothersome--but not lethal--seasonal illness.
Influenza, experts say, is a potentially life-threatening illness with distinct symptoms such as very high fever and severe body aches, lasting no less that five days. The generic “flu” typically lasts from two to four days.
Influenza kills about 20,000 people in the U.S. every year. The majority are elderly or have immune system problems. For most people, influenza might simply lead to an unpleasant couple of days off.
But every once in a while, the virus becomes much more dangerous, as it acquires the ability to attack a broader segment of the population.
By deciphering the genetic code of the virus, researchers learned exactly how the deadly change happens. They discovered how easily the virus shuffles around the basic units that make up its DNA. Like chameleons, influenza viruses constantly reinvent themselves.
Every year, the human influenza virus changes a little, just enough to fool our immune system.
“That’s your garden-variety, year-by-year influenza,” Reid said.
Much of the illness and death caused by the different strains can be prevented with a vaccine, which must be created yearly to protect humans from the latest strain’s novel design.
But at some point, the shuffling of DNA is so radical that the virus essentially becomes a total stranger to the human population, escaping recognition by the immune system altogether.
Rendering humans defenseless, the virus kills with a more aggressive form of the disease. As the more aggressive virus spreads, so does the beginning of a possible pandemic.
And if a pandemic were to hit today, scientists know they’d be running against the clock. With thousands of flights shuffling passengers all over the world, it is estimated that a deadly virus would take four days--and not months, as in 1918--to circle the globe.
Aware of the consequences that a pandemic would have in today’s high-tech environment, the World Health Organization and the U.S. government are starting to take preventive measures seriously.
The WHO has established guidelines for responding to a pandemic, as well as a global influenza program that centralizes data on emerging influenza epidemics around the world.
In the United States, the Working Group on Influenza Pandemic Planning Preparedness and Emergency Response--made up of members from the public and private sector--has been working on an action plan since 1993.
But planning at the local level is as important as establishing national guidelines, said Patricia Schwartz, project coordinator for the California Influenza Pandemic Planning Committee.
In California, representatives from several agencies, including the Red Cross and the Office of Emergency Services, recently met to develop a statewide influenza pandemic plan as part of a pilot project funded by the Centers for Disease Control.
One impending problem has been the lack of real numbers to help agencies foresee the consequences of a pandemic at the local level, said Schwartz. State agencies have had to extrapolate from national estimates, a less than accurate way of gauging the real scope of a pandemic, she said.
The estimate for California, for example, is 9 million cases of influenza leading to 396,000 hospitalizations and about 168,000 deaths, she said. But those numbers are very rough, and represent one scenario out of many during a pandemic.
New software will allow states, counties and cities to refine those numbers. The program, created by Dr. Martin Meltzer and colleagues at the Centers for Disease Control, asks for key information from local hospitals and other agencies.
For example, planners must put in numbers from hospital records on how many people have diabetes or chronic respiratory disease, factors known to exacerbate the impact of influenza. Taking those variables into consideration can provide a more realistic figure for the scope of a pandemic, Schwartz said.
The program allows calculation of different levels of severity, such as comparing what would happen if 20% of the population became infected, versus 50%.
“It gives you honest-to-goodness numbers,” said Schwartz.
Another feature is that planners may visualize different scenarios for vaccination. In case of a pandemic, not enough vaccine will be made quickly enough to protect the whole population, experts say, so states and cities will be faced with a tough choice.
Should the most vulnerable citizens--children and the elderly--be vaccinated, which would save more lives? Or should the bulk of the work force be protected, to prevent a major effect on the economy?
Meltzer said the idea is not to plan once and then forget about it. States and cities have to make the plan a living one and revisit it frequently, he said.
“We can’t expect the federal government to do everything. States and local health departments have to have their plan as well,” Meltzer said.
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Mutating Into a Mass Killer
Every few decades, an aggressive form of the influenza virus renders humans defenseless, killing millions around the world. Three global epidemics, or pandemics, of influenza have taken place in the 20th century alone. Scientists are beginning to understand how the influenza virus every once in a while turns into a mass killer, and national, state and local agencies are getting ready for the possibility that another influenza pandemic may hit soon. *