Researchers dream up a new cause for narcolepsy

Doctors administering the H1N1 vaccine recently got a strange wake-up call. Their patients were mysteriously falling asleep. It got so bad that it was suspected that a certain batch of the H1N1 vaccine caused narcolepsy--a neurological disease characterized by frequent daytime sleep attacks. Emmanuel Mignot, a narcolepsy expert at Stanford, studied H1N1 patients in China. Surprisingly, he found it was the H1N1 virus, and not the vaccine, that was causing the narcolepsy. Mignot published the findings on Aug. 22 issue in Annals of Neurology.

Mignot's research showed that narcolepsy cases peaked 5 to 7 months after H1N1 or flu/cold infections peaked. "Together with recent findings, these results strongly suggest that winter airway infections such as influenza A (including H1N1), and/or Streptococcus pyogenes are triggers for narcolepsy," Mignot, a professor of psychiatry and behavioral sciences, and his colleagues wrote in the paper. "The new finding of an association with infection, and not vaccination, is important as it suggests that limiting vaccination because of a fear of narcolepsy could actually increase overall risk."

Researchers believe narcolepsy sufferers have a genetic predisposition to the disease, but that environmental factors kick in that force the immune system to kill the neurons that produce the protein hypocretin, which promotes wakefulness. Past studies have shown upper airway infections could trigger the disease, Mignot said in the release. It is also possible that vaccination could also decrease your risk of narcolepsy.

- read the Stanford University Medical Center release