spicpussy
2009-11-28 17:33:17 UTC
Uh, but we don't wish to put a crimp in your mobility ... just a few
thoughts ...
------------------------
"Is there a history lesson from the swine flu of '76?"
"Scientists look closely for side effects of vaccine after earlier
version caused outbreak of rare form of paralysis"
By David Brown
Saturday, November 28, 2009
AS MORE AND MORE PEOPLE receive the H1N1 shot, an earlier vaccine is
casting a mysterious shadow over the attempt to immunize 200 million
people in the next few months.
A vaccine made in 1976 in response to a different strain of H1N1
influenza led to an outbreak of a rare form of paralysis. Of the 43
million people who were vaccinated, about 400 developed Guillain-Barré
syndrome (GBS), and 25 died.
Whether an equally unexpected surprise might be lurking in this year's
swine flu shot is a big -- although not publicly acknowledged --
question hanging over the current immunization effort. That
possibility is why the Centers for Disease Control and Prevention
routinely reports, as it did Wednesday, on whether any notable side
effects to the new vaccine have been discovered. (None have.)
Unlike today's bug, the 1976 virus never took off from where it
originated at an army base in New Jersey. With nothing to be gained
from vaccination, the widespread campaign was halted after less than
three months.
For the 15 years after the "swine flu affair," scientists sought to
nail down whether and how much the 1976 vaccine increased a person's
risk of GBS. Almost nothing, however, was done to figure out how and
why the flu shot had that effect. It's an oversight some public health
officials are coming to regret.
"We should have made an exhaustive attempt to understand what happened
from a biological standpoint," said Michael T. Osterholm, a physician
who heads the Center for Infectious Disease Research and Policy.
Both the 1976 strain and the new H1N1 strain are closely related to
viruses carried by pigs, making some wonder whether that "swinishness"
makes their vaccines more likely to cause unusual effects.
"That is the right question to ask," said Peter Palese, an influenza
virologist at Mount Sinai School of Medicine in New York. "And I would
like to say that no one really knows."
Researchers stopped looking back at 1976, Osterholm said, when there
were no subsequent problems with flu vaccines. "After we had a couple
of seasons under our belt when there was no unusual risk to regular
flu vaccines, we just let it go," he said.
Today's H1N1 vaccine is made, tested and administered the same way the
seasonal flu vaccine is. There's no reason to think it's any more
dangerous than the regular flu shot, whose risk of serious side
effects is essentially zero.
But that was true of the 1976 vaccine, too.
A spike in cases?
Named after two French physicians who described it in 1916, Guillain-
Barré [GEE-yan bah-RAY] syndrome causes weakness and tingling that
starts in the legs, but over weeks can affect most of the body's
muscles. The symptoms occur because the insulation on the outside of
nerve fibers breaks down, damaging the normal conduction of impulses.
In normal times, GBS occurs at a rate of roughly 2 cases per 100,000
people per year. Although only about 5 percent die, up to a third
spend time in an intensive care unit on a ventilator before they get
better. Nearly a third still have some weakness three years later.
After the 1976 vaccination campaign was halted on Dec. 16 of that
year, much work went into figuring out whether the increase in GBS
cases was real, or just a random upward blip.
Careful counting in defined populations -- most important, the entire
states of Minnesota and Michigan -- proved beyond doubt that it was
real: The risk of developing the condition rose four- to seven-fold in
the six weeks after getting the swine flu shot. The number of cases
attributable to the vaccine ranged from 5 to 12 per million people
vaccinated.
Studies of vaccines before they go on the market have too few people
in them to uncover adverse events occurring at such very low
frequency. That's why the GBS risk was not detected in the testing of
the 1976 vaccine -- and why it would not be caught in this year's
testing, either.
Researchers looked for spikes in GBS among people vaccinated for flu
in subsequent seasons and did not find any. The only exceptions were
1992-93 and 1993-94. When those two seasons were combined, people
getting flu shots had a slightly higher risk of GBS -- about 1 extra
case per million. The conclusion was that 1976 was a fluke, unlikely
to happen again.
Comparing the vaccines
There's some evidence that the 1976 vaccine may have triggered GBS
through a mechanism known as molecular mimicry.
About two-thirds of cases of GBS arise after an intestinal or
respiratory infection (including flu). The biggest cause is a
bacterium responsible for food-borne illness, Campylobacter jejuni.
Campylobacter can stimulate the immune system to make antibodies
against a nerve-sheath substance called ganglioside, and that
presumably leads to the condition.
However, not all people with the syndrome have nerve-attacking
antibodies, and millions of people get Campylobacter infections
without getting GBS. So clearly there are unknown factors -- some
almost certainly genetic -- involved in the disease. The 1976 vaccine
may have triggered GBS in much the way that Campylobater does. The
evidence comes from experiments done by Irving Nachamkin, a
microbiologist at the University of Pennsylvania, and published last
year.
Nachamkin had access to a few unopened vials of the 1976 vaccine,
which he tested for the presence of Campylobacter bacteria. He found
none, putting to rest the theory that the 1976 GBS cases were the
consequence of contaminated vaccine. He then injected the vaccine into
mice. All developed antibodies against GM1, a form of ganglioside.
"We were just as surprised as anyone when we found this," Nachamkin
said. "The real question is: Is it relevant to Guillain-Barré
syndrome?"
What's confusing is that animals injected with flu vaccines from 1991
and 2004 also developed the anti-GM1 antibodies ( as did some animals
infected with the even more distantly related H5N1 bird flu strain).
Furthermore, none developed muscle weakness. Researchers at CDC are
hunting down blood samples from people who got the 1976 vaccine to see
if they contain antibodies to ganglioside, or hold any other hints as
to what might have made that flu shot have that rare side effect.
Today, both the federal government's epidemiologists and pretty much
every neurologist in America have eyes wide open for cases of GBS.
As of last week, six cases of GBS in people who had gotten the H1N1
vaccine had been reported to the federal government's Vaccine Adverse
Event Reporting System. (Four more are under investigation.) The six
people with confirmed cases live in Maryland, Virginia, New York,
Connecticut, Florida and Illinois. In each case, the person came down
with neurological symptoms within two days being vaccinated -- almost
certainly too soon to be a consequence of the vaccine.
"At this point, we are not seeing any evidence there is an increase in
Guillain-Barre syndrome," said James J. Sejvar, the physician leading
CDC's surveillance for it.
A survey by the Harvard School of Public Health earlier in the fall
found that about half of American adults have no plans to get the
pandemic flu vaccine. Only one-third said they thought it was "very
safe" for most people.
Even if there were to be a slight increase in GBS, some public health
officials believe it would still be worth getting vaccinated.
"I think the numbers of people who would be saved from serious illness
or death would be far greater," said Palese.
The emerging picture of the 2009 pandemic seems to bear out that
hunch.
For every 100,000 people vaccinated, the 1976 vaccine was responsible
for just under 1 case of GBS. A CDC analysis this month revealed that
out of every 100,000 people who come down with the pandemic flu, 18
die from it.
http://www.washingtonpost.com/wp-dyn/content/article/2009/11/27/AR2009112703248.html
thoughts ...
------------------------
"Is there a history lesson from the swine flu of '76?"
"Scientists look closely for side effects of vaccine after earlier
version caused outbreak of rare form of paralysis"
By David Brown
Saturday, November 28, 2009
AS MORE AND MORE PEOPLE receive the H1N1 shot, an earlier vaccine is
casting a mysterious shadow over the attempt to immunize 200 million
people in the next few months.
A vaccine made in 1976 in response to a different strain of H1N1
influenza led to an outbreak of a rare form of paralysis. Of the 43
million people who were vaccinated, about 400 developed Guillain-Barré
syndrome (GBS), and 25 died.
Whether an equally unexpected surprise might be lurking in this year's
swine flu shot is a big -- although not publicly acknowledged --
question hanging over the current immunization effort. That
possibility is why the Centers for Disease Control and Prevention
routinely reports, as it did Wednesday, on whether any notable side
effects to the new vaccine have been discovered. (None have.)
Unlike today's bug, the 1976 virus never took off from where it
originated at an army base in New Jersey. With nothing to be gained
from vaccination, the widespread campaign was halted after less than
three months.
For the 15 years after the "swine flu affair," scientists sought to
nail down whether and how much the 1976 vaccine increased a person's
risk of GBS. Almost nothing, however, was done to figure out how and
why the flu shot had that effect. It's an oversight some public health
officials are coming to regret.
"We should have made an exhaustive attempt to understand what happened
from a biological standpoint," said Michael T. Osterholm, a physician
who heads the Center for Infectious Disease Research and Policy.
Both the 1976 strain and the new H1N1 strain are closely related to
viruses carried by pigs, making some wonder whether that "swinishness"
makes their vaccines more likely to cause unusual effects.
"That is the right question to ask," said Peter Palese, an influenza
virologist at Mount Sinai School of Medicine in New York. "And I would
like to say that no one really knows."
Researchers stopped looking back at 1976, Osterholm said, when there
were no subsequent problems with flu vaccines. "After we had a couple
of seasons under our belt when there was no unusual risk to regular
flu vaccines, we just let it go," he said.
Today's H1N1 vaccine is made, tested and administered the same way the
seasonal flu vaccine is. There's no reason to think it's any more
dangerous than the regular flu shot, whose risk of serious side
effects is essentially zero.
But that was true of the 1976 vaccine, too.
A spike in cases?
Named after two French physicians who described it in 1916, Guillain-
Barré [GEE-yan bah-RAY] syndrome causes weakness and tingling that
starts in the legs, but over weeks can affect most of the body's
muscles. The symptoms occur because the insulation on the outside of
nerve fibers breaks down, damaging the normal conduction of impulses.
In normal times, GBS occurs at a rate of roughly 2 cases per 100,000
people per year. Although only about 5 percent die, up to a third
spend time in an intensive care unit on a ventilator before they get
better. Nearly a third still have some weakness three years later.
After the 1976 vaccination campaign was halted on Dec. 16 of that
year, much work went into figuring out whether the increase in GBS
cases was real, or just a random upward blip.
Careful counting in defined populations -- most important, the entire
states of Minnesota and Michigan -- proved beyond doubt that it was
real: The risk of developing the condition rose four- to seven-fold in
the six weeks after getting the swine flu shot. The number of cases
attributable to the vaccine ranged from 5 to 12 per million people
vaccinated.
Studies of vaccines before they go on the market have too few people
in them to uncover adverse events occurring at such very low
frequency. That's why the GBS risk was not detected in the testing of
the 1976 vaccine -- and why it would not be caught in this year's
testing, either.
Researchers looked for spikes in GBS among people vaccinated for flu
in subsequent seasons and did not find any. The only exceptions were
1992-93 and 1993-94. When those two seasons were combined, people
getting flu shots had a slightly higher risk of GBS -- about 1 extra
case per million. The conclusion was that 1976 was a fluke, unlikely
to happen again.
Comparing the vaccines
There's some evidence that the 1976 vaccine may have triggered GBS
through a mechanism known as molecular mimicry.
About two-thirds of cases of GBS arise after an intestinal or
respiratory infection (including flu). The biggest cause is a
bacterium responsible for food-borne illness, Campylobacter jejuni.
Campylobacter can stimulate the immune system to make antibodies
against a nerve-sheath substance called ganglioside, and that
presumably leads to the condition.
However, not all people with the syndrome have nerve-attacking
antibodies, and millions of people get Campylobacter infections
without getting GBS. So clearly there are unknown factors -- some
almost certainly genetic -- involved in the disease. The 1976 vaccine
may have triggered GBS in much the way that Campylobater does. The
evidence comes from experiments done by Irving Nachamkin, a
microbiologist at the University of Pennsylvania, and published last
year.
Nachamkin had access to a few unopened vials of the 1976 vaccine,
which he tested for the presence of Campylobacter bacteria. He found
none, putting to rest the theory that the 1976 GBS cases were the
consequence of contaminated vaccine. He then injected the vaccine into
mice. All developed antibodies against GM1, a form of ganglioside.
"We were just as surprised as anyone when we found this," Nachamkin
said. "The real question is: Is it relevant to Guillain-Barré
syndrome?"
What's confusing is that animals injected with flu vaccines from 1991
and 2004 also developed the anti-GM1 antibodies ( as did some animals
infected with the even more distantly related H5N1 bird flu strain).
Furthermore, none developed muscle weakness. Researchers at CDC are
hunting down blood samples from people who got the 1976 vaccine to see
if they contain antibodies to ganglioside, or hold any other hints as
to what might have made that flu shot have that rare side effect.
Today, both the federal government's epidemiologists and pretty much
every neurologist in America have eyes wide open for cases of GBS.
As of last week, six cases of GBS in people who had gotten the H1N1
vaccine had been reported to the federal government's Vaccine Adverse
Event Reporting System. (Four more are under investigation.) The six
people with confirmed cases live in Maryland, Virginia, New York,
Connecticut, Florida and Illinois. In each case, the person came down
with neurological symptoms within two days being vaccinated -- almost
certainly too soon to be a consequence of the vaccine.
"At this point, we are not seeing any evidence there is an increase in
Guillain-Barre syndrome," said James J. Sejvar, the physician leading
CDC's surveillance for it.
A survey by the Harvard School of Public Health earlier in the fall
found that about half of American adults have no plans to get the
pandemic flu vaccine. Only one-third said they thought it was "very
safe" for most people.
Even if there were to be a slight increase in GBS, some public health
officials believe it would still be worth getting vaccinated.
"I think the numbers of people who would be saved from serious illness
or death would be far greater," said Palese.
The emerging picture of the 2009 pandemic seems to bear out that
hunch.
For every 100,000 people vaccinated, the 1976 vaccine was responsible
for just under 1 case of GBS. A CDC analysis this month revealed that
out of every 100,000 people who come down with the pandemic flu, 18
die from it.
http://www.washingtonpost.com/wp-dyn/content/article/2009/11/27/AR2009112703248.html