This is what all this "shortage" fuss was all about - it's simply a
marketing strategy:
All this "shortage" bull was/is simply intended to push FluMist -
scroll down to the end of this story:
http://www.abcnews.go.com/wire/US/ap20031209_2285.html
Flu Vaccine's Strength Worries Experts
Health Experts Worry That Flu Shots Taken by Millions of Americans
Will Offer Weaker Protection
The Associated Press
Dec. 9 - As flu sweeps across the country, many health experts are
worried that the shots taken by tens of millions of Americans will
offer considerably weaker protection than any flu vaccine in recent
years.
The flu shot available this year was formulated to protect against
three strains of the virus. But the strain actually circulating this
year is somewhat different from those three, and it is probably too
late to develop a new formula.
Even though one of the three is a close cousin of this season's bug,
whether that will be enough to help people ward off the flu is simply
unknown. Some experts expect the level of protection to be 50 percent
or less.
Most agree the vaccine will do at least some good. But the
word "some" is about specific as scientists at the Centers for
Disease Control and Prevention are willing to get.
Even in the best of years, the flu shot is not foolproof. Ordinarily
it is between 70 percent and 90 percent effective in healthy young
adults and somewhat less effective in the elderly.
The last time the vaccine missed the mark was in 1997, when a strain
called A-Sydney appeared that was significantly different from the
strain included in the flu shot. Doctors are still uncertain about
how much good the shot did that season, although the CDC estimates it
was 30 percent to 50 percent protective.
Scientists say this year's mismatch does not seem to be as great as
it was six years ago, but they cannot say with certainty how well the
flu shot will work, or even whether it will.
"With a vaccine with a less optimal match, you have to say it might
not work at all," said Dr. Scott Harper, a CDC
epidemiologist. "That's very unlikely. Probably it will not be 90
percent effective. But we just have no good sense of how it will work
in humans. Biology is messy."
The mismatch occurred when experts decided to include a strain called
A-Panama in this year's shot, the same as last year. It turns out
that the dominant virus this fall has been A-Fujian, which has two
genetic mutations that make it different.
A variety of studies using ferrets, the primary lab animal for flu
experiments, and human blood suggest that the A-Panama shots should
offer at least partial protection against A-Fujian. The most
encouraging predictions come from the World Health Organization,
which, along with the U.S. Food and Drug Administration, decides what
strains of flu virus will be included in the shot.
Dr. Klaus Stohr said blood taken from people who got this year's shot
shows they have 41 percent fewer antibodies against A-Fujian than
they do against A-Panama, and three-quarters of vaccinated adults
have enough antibodies to protect against A-Fujian.
"The data indicate that the vaccine in use does protect to a good
extent against the currently circulating strain," Stohr said.
However, Harper said human blood samples and ferret experiments
cannot be reliably used to predict how well a vaccine will work. The
CDC is doing several studies to estimate how well people are
protected in areas where the flu is circulating, but the answer
probably will not be known until the end of the flu season.
Dr. Walt Orenstein, director of the CDC's National Immunization
Program, said it is probably too late to create an additional vaccine
for this season, although manufacturers are working with the A-Fujian
strain. "I won't rule it out, but it's unlikely," he said.
Meanwhile, doctors continue to urge people to get vaccinated, even
though supplies are running short, because the vaccine may help make
the flu less severe, even if it fails to give complete protection. It
also protects against two other flu strains that could appear later
in the season.
Dr. Sandra Kemmerly, associate head of infectious diseases at the
Oschner Clinic in New Orleans, said there is already anecdotal
evidence that the shots are helping people escape the worst of the
flu.
"Of the people we are seeing who were vaccinated and have flu-like
symptoms, it is much milder than if they had not been vaccinated at
all," she said.
Dr. Theodore Eickhoff of the University of Colorado, a member of the
FDA advisory committee that chose this year's vaccine, estimated it
will be less than 50 percent effective at preventing the flu. "It's a
guess based on prior years' experience with variant strains," he said.
Dr. William Schaffner, head of preventive medicine at Vanderbilt
University, noted that even a vaccine that is 50 percent effective
may turn a serious illness into a milder one and help protect those
who are especially vulnerable, such as the elderly, against pneumonia
and death.
"There is no doubt that all of us are concerned," Schaffner said.
Doctors said there is circumstantial evidence suggesting that the
FluMist nasal spray vaccine, which uses a weakened live virus, may do
a better job of protecting against a mismatched virus.
Dr. Robert Belshe of St. Louis University said FluMist was tested in
children during the season when A-Sydney emerged, and it still
appeared to be 86 percent protective. More than 90 percent of
children given FluMist that year made antibodies against the new
strain, compared with less than a third who received standard flu
shots.
This year, manufacturers made 83 million doses of flu vaccine.
Supplies ran short in some parts of the country as the early and
intense outbreak in Western states increased demand. The CDC said
Tuesday it is working to redistribute remaining U.S. supplies and may
buy fewer than 500,000 more doses from a British maker.
EDITOR'S NOTE: Medical Editor Daniel Q. Haney is a special
correspondent for The Associated Press.
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