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- Last winter's flu season killed thousands more people
in the U.S. than usual, federal epidemiologists said Thursday, raising
the stakes for several new kinds of flu treatments expected to hit the
market in the next few months.
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- Although precise numbers have not been tabulated, officials
from the Centers for Disease Control and Prevention said at a Washington,
D.C., news conference Thursday that last season's flu deaths easily surpassed
the yearly average of 20,000 fatalities nationwide, out of 20 million estimated
cases overall. They trace the causes to everything from low vaccination
rates in minority communities to unexpected outbreaks on cruise ships in
Alaska the past two years.
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- "One of the most important factors is that a lot
of serious complications and deaths happen among the elderly, and that
segment of the population has increased tremendously in recent years,"
said Dr. Keiji Fukuda, chief of influenza epidemiology at the CDC.
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- Such dangers have set off an intense race among drugmakers
to bring the next generation of flu vaccines and remedies to market, as
the traditional window for flu vaccination opens this month.
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- Already this year the Food and Drug Administration has
approved Relenza, an inhaler made by Glaxo-Wellcome that prevents a flu
virus from making copies of itself. Regulators are reviewing Hoffman-LaRoche's
oseltamivir, which works on the same principle. Both drugs can reduce the
disease's severity and duration by up to 30 percent and may prevent some
people from getting infected, according to studies.
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- Although neither Relenza nor oseltamivir, also known
as Tamiflu, is intended to replace flu shots, officials at the biotech
company Aviron expect to submit a radical new vaccine called FluMist for
federal approval later this year. That drug would be the first flu vaccine
administered as a nasal spray.
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- "That could bring the vaccine to groups that have
not been vaccinated before," Fukuda said. "For children especially,
the idea of being able to get vaccinated without a needle is nice."
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- The CDC is considering recommending that all adults over
50 and all preschool children get annual flu shots. The current recommendations
cover only adults over 65 and people with weakened immune systems.
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- One of the main uses of therapies such as Relenza and
Tamiflu may be for people who know they've been exposed to the virus, or
who wait too long to get their flu shots, experts say. The drugs start
to fight the virus right away unlike vaccines, which take at least two
weeks to build up antibodies that ward off infection.
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- To exploit the special benefits of antiviral therapies,
the makers of both drugs are planning unprecedented marketing blitzes that
will target specific cities as health officials detect outbreaks there.
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- "We want to make sure we're giving this to people
who really need it," said Charles Alfaro, director of public affairs
at Hoffman-LaRoche. "We've found that doctors are better at diagnosing
the disease when they know flu is in a given area."
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- The companies' first task will be to persuade consumers
they're better off taking sophisticated antiviral medication than taking
cheaper over-the-counter drugs, said Dr. Frederick Hayden, a clinical virologist
at the University of Virginia who has led research on both drugs.
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- "People tend to tough it out," Hayden said.
"They expect to get better after a few days. For the new drugs to
work, we'll have to see a shift in how patients seek care."
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- Yet widespread advertising could flood emergency rooms
unnecessarily with people who are suffering from ordinary cold symptoms,
said Dr. John Flaherty, an infectious disease specialist at the University
of Chicago.
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- "It will be interesting to see how many people come
in because of cold symptoms and then insist on getting the new drugs,"
Flaherty said.
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- The companies' pitches to doctors will include warnings
about the deadly potential of the seemingly innocuous flu virus, which
killed an estimated 20 million people worldwide in a 1918-1919 outbreak.
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- Until this year, the only options for fighting influenza
infections were the drugs amantadine and rimantadine, which fight just
one strain of the virus and can have serious side effects such as depression
or seizures. Both drugs work by keeping the virus from releasing its genetic
material inside human cells and using them as a factory to churn out more
copies of itself.
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- The newer medications, in contrast, are called "plug
drugs" because they clog a chemical site on the virus surface--the
enzyme neuraminidase--that influenza needs to emerge from one infected
cell and spread to others.
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- Hayden has found that this approach can fight off both
the A and B flu strains with few side effects, and may also keep the virus
from getting an initial foothold in the mucus lining of the respiratory
tract. His most recent results, for the Tamiflu pill, were published Wednesday
in the Journal of the American Medical Association.
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- In the course of designing such finely targeted drugs,
researchers have amassed detailed molecular maps of the virus surface that
help explain why some flu varieties are so deadly.
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- The latest such outbreak happened in Hong Kong in 1997,
when a strain of "bird flu" infected 18 people and killed six,
raising the concern of health officials worldwide before the virus disappeared
as mysteriously as it had appeared.
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- Researchers found that, unlike most flu viruses that
can infect only the respiratory tract, the Hong Kong strain was unusually
deadly because its surface chemistry allowed it to damage many different
types of cells.
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- "That virus had the ability to go into the bloodstream
and infect other parts of the body," said Robert Lamb, a professor
of biochemistry and an influenza expert at Northwestern University.
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- Having antiviral drugs for flu may be essential if the
next lethal strain begins to spread before scientists can develop and distribute
a vaccine, experts say.
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- One obstacle to the new therapies will be cost. A five-day
course of Relenza runs about $40, at least four times the expense of over-the-counter
drugs or flu shots.
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- In a preview of concerns that likely will drive U.S.
managed-care insurers' response to the new drugs, Glaxo-Wellcome has estimated
that introducing Relenza would cost the British National Health Service
up to $25 million this flu season. Glaxo-Wellcome says the expense has
British officials considering barring government doctors from prescribing
the drug, a move many pharmaceutical companies say would stifle the development
of such therapies.
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