The swine flu (H1N1) in general is linked to narcolepsy and encephalitis.
There was a large outbreak of narcolepsy following the 1918 swine flu pandemic, and researching it gave rise to the modern field of neurology.
http://www.mollycrosby.com/book_asleep.html
In this extraordinary book, the author of The American Plague tells the story of a sleeping sickness epidemic that has been largely forgotten in the shadow of the Spanish Flu that accompanied it. Set in fascinating 1920s and 30s New York, it follows a group of physicians through hospitals and insane asylums as they try to solve a worldwide pandemic. With symptoms ranging from Parkinson’s to violent insanity, it would also become a catalyst for the advancement of an entire field of medical study: neurology.
To this day, doctors do not know what caused the pandemic of encephalitis lethargica—literally, “the encephalitis that makes you sleepy.” They do know, however, that cases still occur today, and an epidemic is likely to re-emerge in the wake of the next flu pandemic. Asleep takes the reader into the frightening history of this mysterious disease—and the fight to conquer it before it strikes again