(New Scientist) An unusual increase in narcolepsy cases in Europe was linked to a new flu vaccine used there, and now researchers may have figured out why: A protein in the vaccine appears to mimic one in the brain that plays a role in the sleep disorder.
People with narcolepsy experience severe daytime sleepiness and "sleep attacks," in which they suddenly fall asleep for a short time. The vaccine that was linked to the disorder was used in 2009 and 2010 to protect against the H1N1 strain of flu, which is sometimes called the swine flu.
The new findings also suggest that the immune system may play a role in the disorder, and that in rare cases vaccines or infections can trigger narcolepsy in people with a certain genetic mutation.
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