sleep episodes can occur at any time. People may unwillingly fall asleep while at work or at school, when having a conversation, playing a game, eating a meal, or, most dangerously, when driving an automobile or operating other types of machinery.
It was suspected that vacine adjuvants may have been causing the problem. Adjuvants are compounds that have been added to a vaccine to increase an immune response to the pathogen the vaccine is targeting. Examples of adjuvants are such things as aluminum hydroxide, or more specifically in this case, squalene (a protein found in shark liver oil, or plant oils).
However, researchers investigating an outbreak of the Swine Flu in China are seeing narcolepsy associated with infection in individuals who did not receive the vaccine or had the vaccine without an adjuvant. Hmmm. It appears that now the narcolepsy associated with the vaccine, may actually be attributable to the actual infection.
One hypothesis that has been generated by the Stanford Center for Narcolepsy is that a severe respiratory infection may actually induce the body to go to sleep. This has been supported in another report they site where some Strep infections also induce narcolepsy.
So it could be an immune response to an infection telling your body to rest while it fights? What is also interesting is that there is a genetic tie for a specific HLA molecule (DQB1*0602) in individuals who have narcolepsy, indicating another immunological link with the disease. So this means that you are genetically predisposed to sudden and irresistible bouts of sleep? Also from the NIH:
Other factors such as infection, immune-system dysfunction, trauma, hormonal changes, and stress may also be present before the disease develops.
As Alice would say “Curiouser and curiouser.”