Scientists find new
evidence on GSK vaccine link to narcolepsy
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[July 02, 2015]
By Kate Kelland
LONDON, (Reuters) - Scientists
investigating why a GlaxoSmithKline flu vaccine triggered narcolepsy in
some people say they have the first solid evidence the rare sleep
disorder may be a so-called "hit-and-run" autoimmune disease.
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The researchers were trying to find out why, of two different flu
vaccines widely deployed during the 2009/2010 swine flu pandemic,
only one -- GSK's Pandemrix -- was linked with a spike in cases of
narcolepsy.
In a study published in the journal Science Translational Medicine,
they said the answer could lie in a protein in the H1N1 flu strain
found in high amounts in the GSK shot but at much lower levels in
the other vaccine, Novartis' Focetria.
"It was a really exciting moment," Lawrence Steinman, a professor of
neurology and neurological sciences who led the work at Stanford
University, said of the finding.
A spokeswoman for GSK, whose Pandemrix vaccine was withdrawn from
the market after the 2009/2010 pandemic, said the company was aware
of the study and would "review it carefully".
"We are actively conducting research into the observed association
between Pandemrix and narcolepsy and the interaction this vaccine
might have had with other risk factors in those affected," she said
in an emailed comment.
Narcolepsy is an incurable, lifelong brain disorder that disrupts
normal sleep-wake cycles and causes severe nightmares and daytime
sleep attacks that can strike at any time.
Scientists are not sure exactly what causes it, but the latest
research suggests it is a type of auto-immune disease, where the
immune system misfires and mistakenly attacks the body's own
functions and organs.
Studies in countries where GSK's Pandemrix vaccine was used in the
2009/2010 flu pandemic -- including Britain, Finland, Sweden and
Ireland -- have found a significant rise in cases of narcolepsy in
children.
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Narcolepsy patients have been shown to have a loss of function in
"wakefulness" cells called hypocretin cells in one of the brain's
sleep centres.
In their study, Steinman's team found that H1N1 pandemic flu
contains a protein whose structure partly mimics a portion of a
hypocretin receptor in the brain. This H1N1 protein was contained in
both vaccines studied, but at much higher levels in GSK's Pandemrix
than in Novartis' Focetria.
The scientists said they now believe the narcolepsy in people
vaccinated with Pandemrix was caused by a so-called "hit and run"
mechanism, in which high levels of the H1N1 protein stimulated the
production of large amounts of antibodies to both the virus and the
hypocretin receptor.
(Editing by Larry King)
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