Flu Pandemic Controllable with Multifaceted Strategy
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There may be a strategy to battle a flu pandemic. The fear is a catastrophic spread of the disease like the pandemic in 1918. But a federally financed project now shows there is a way to beat it. It involves a novel use of an old tool: vaccination.
NPR's Richard Knox has the story.
RICHARD KNOX reporting:
The project makes use of a big computer array at Los Alamos National Laboratory in New Mexico. Catherine Macken explains how she and her colleagues there use the supercomputer to analyze pandemic flu.
Dr. CATHERINE MACKEN (research scientist, Los Alamos National Laboratory): We use computer programs to mimic individual people. These are fictitious people. The computer code represents individuals, and it also represents ways in which groups of individuals interact with each other.
KNOX: Virtually every American: where they live, where they work or go to school, how many other Americans they'd encounter every day during the six months it would take for a pandemic to sweep through the country.
By plugging in assumptions about how infectious a pandemic virus might be, the computers painted a picture of what the next pandemic could look like. The results are in the proceedings of the National Academy of Sciences.
Dr. IRA LONGINI (Biostatistics and Biomathematics, Rollins School of Public Health, University of Washington): If pandemic influenza entered the U.S. and nothing were done, we'd expect to see, before it's over, about 122 million ill Americans.
KNOX: That's Ira Longini, of the University of Washington, another member of the team.
He says the computer-simulated pandemic peaks 85-days after the virus enters the country. At that point, four and a half million people would be getting sick every day.
But that's if nothing were done. What impact would there be from various strategies, such as the use of the anti-viral drug Tamiflu If the pandemic virus were as contagious as the 1918 strain, Longini says:
Dr. LONGINI: We'd need at least 182 million courses, and that would be an extremely large stockpile.
KNOX: Today the government's Tamiflu stockpile contains only 5 million treatment courses. Even the government's Tamiflu stockpile target is less than half what the computer says would be necessary if Tamiflu's going to be the bulwark of our defense.
Next, the researchers looked to the impact of vaccine, and they found something fascinating. Even a weak vaccine would yield huge benefits.
Dr. LONGINI: Such a vaccine would have to be roughly 30 percent effective against illness and infection, and about 50 percent effective against transmission to others.
KNOX: That's much lower than standard vaccines. But there's no way to make a potent vaccine against a pandemic flu virus in advance. The best you can do is make a vaccine against the virus most-likely to turn pandemic. That vaccine wouldn't be a close match, but Longini says it could be close enough.
Dr. LONGINI: You could cut the number of ill people in the U.S. by two-thirds, and that would reduce a pandemic spread to something similar to what we see every year.
KNOX: But 250 million Americans would need to be vaccinated as fast as possible, preferably beginning before the virus crossed our borders.
Could the nation carry out that kind of mass vaccination campaign? Some cities, such as Seattle, are gearing up to try.
Ms. MICHELLE PENNYLEGION (head of education services at Seattle's King County Health Department): We're standing outside of a community center, and its connected to a playground and a play field.
KNOX: Michelle Pennylegion, of the Seattle King County Health Department, is showing off one of two dozen community centers that would become mass vaccination clinics when a pandemic strikes.
Ms. PENNYLEGION: People would be asked to park over there and then walk around and then enter right through that door.
KNOX: Last November, a drill here, using regular flu vaccine, went off without a hitch. Pennylegion says four similar sites are ready to go.
Ms. PENNYLEGION: We believe we could ramp up and get these medication centers up and running within 12 hours of the order to do so. That is our goal, and we believe that we could do that today.
KNOX: The computer simulation suggests the nation would need to get the vaccine into ten million arms a week. That translates into nearly 70,000 residents of Seattle and surrounding King County a week. Penny legion says they couldn't do that now; they'll need more trained staff.
Most crucially, they'll need the vaccine.
Ms. PENNYLEGION: If this were to happen tomorrow, we don't have vaccine. And we don't have a supply of Tamiflu to give to the general public. So our medication centers are not useful.
KNOX: But a year from now, they might be relevant.
Ms. PENNYLEGION: They may be relevant, right.
KNOX: Stewart Simonson agrees the nation could vaccinate that many people that fast. He's assistant secretary for Emergency Preparedness of the U.S. Department of Health and Human Services.
Getting enough vaccine doses is the rub.
Mr. STEWART SIMONSON (assistant secretary for Emergency Preparedness of the U.S. Department of Health and Human Services): If we're talking about producing something like eight, nine, ten million a year, which is what we are right now, in advance of the pandemic, its sometime before we're going to have the capability to roll out ten million doses a week.
KNOX: He says the important message from the computer simulation is that putting together all the possible strategies, including school closures and the willingness of people to keep their distance from others, could tame a pandemic.
Another computer simulation to be published later this spring comes to the same conclusion.
Mr. SIMONSON: If we combine the vaccine that we have with the anti-virals that we have with traditional public health measures, like social distancing, we can do something about it. We're not powerless.
KNOX: It all comes down to how much time there is to prepare. Richard Knox NPR, News.
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