Influenza A (including H1N1 infection) May Trigger Narcolepsy

by julie on August 22, 2011

What causes narcolepsy? I wasn’t born with narcolepsy but developed it in my late teens to early 20’s.

Evidence continues to suggest that influenza A (including H1N1) and other winter airway infections play a significant role in narcolepsy onset. However, the role of H1N1 vaccination is a different story, suggests a recent study led by Dr. Emmanuel Mignot.

About 3 million people worldwide have narcolepsy today.  Dr. Mignot’s latest study explores the connection between influenza and narcolepsy in China.

 
The study examined the time of year that patients developed cataplexy and sleepiness, finding that the symptoms usually occurred about 5 to 7 months after the peak flu/cold or H1N1 infection season. The least number of cases developed in November and the most in April.  Researchers believe the seasonal onset pattern is significant. 

“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,” reports the study published today August 22 in Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society.

In  2009, Mignot and colleagues confirmed that narcolepsy is an autoimmune disease, caused when patients’ immune systems kill the neurons that produce the protein hypocretin.

Why does this happen to some people but not others? Scientists believe that  an individual may have a “genetic predisposition to the disease, and some environmental factor kicks his or her immune system into action leading to narcolepsy.” In Caucasians, Streptococcus pyogenes infections, such as strep throat, have been shown to precede narcolepsy onset, similarly indicating that upper airway infections play a role.

“Last year, several European countries reported new cases of narcolepsy in children who had been vaccinated for the H1N1 strain of influenza; children who received the Pandemrix H1N1 vaccine in Finland, for example, faced a ninefold increased risk of narcolepsy,” describes Stanford University’s School of Medicine’s news articletoday.  “The World Health Organization led an investigation and determined that something about this particular vaccine acted in a ‘joint effort’ with ‘some other, still unknown factor’ to increase risk in those already genetically predisposed. (Pandemrix contains two adjuvants to invoke a stronger immune response; these additives are not included in the H1N1 vaccines used in the United States and China.)”

Importantly, this paper suggests a connection between the onset of narcolepsy and H1N1 infection, as opposed to H1N1 vaccination.  In the patients interviewed, very few (about 5.6%) remembered receiving the H1N1 vaccine.  
 
Dr. Mignot believes that there may be a significant difference between the Pandemrix vaccine used in Europe and those used in the United States and China.  More research is underway to determine if and why Pandemrix causes a strong autoimmune reaction and increases the risk of narcolepsy. 
 
However, Dr. Mignot still believes that receiving a H1N1 vaccination (not Pandemrix) is important for personal safety and public health, explaining, “It’s very possible that being vaccinated with a mild vaccine, one without the adjuvants in question, blocks you from getting a big infection that could increase your risk of narcolepsy.”
 
Certainly no one wants to see an increase in narcolepsy cases worldwide as we’ve seen these past few years.  However, the wizard of narcolepsy is hopeful that we are narrowing in on why this is happening, stating, “We’re much closer to understanding what’s happening in the autoimmune destruction of hypocretin cells.” 
 
For more information, please read the news report: “Stanford study draws connection between narcolepsy and influenza,” Stanford University School of Medicine, August 22, 2011.

See also: Donald McNeil Jr., A Surge in Sleepiness in China Appears to Have Been Caused by Flu. New York Times, August 22, 2011.
Martin Beckford, Swine Flu infections trigger narcolepsy, not vaccine, says study. The Telegraph, August 22, 2011.

{ 3 comments… read them below or add one }

Anonymous August 31, 2011 at 7:18 pm

Reading this post reminded me that my senior year of highschool was when I first started yawning at weird times like just before an orchestra performance. I was so excited about performing and couldn't figure out why I was yawning. Is it some weird quirk of mine that I yawn when I'm excited about something? I kept this in the back of my head and found myself yawning on a date, and I liked the guy! He asked about it and I told him that I have this weird quirk…looking back, a lot of guys asked me that and I always just told them it was my weird quirk! Every time I'd ask myself what I was excited about/looking forward to and every time I'd have an answer! I guess there could have been worse things to think about when I yawned, so I guess I preferred my positive way of keeping myself in the dark for as long as I could. Ah, the joys of being young and not taking a yawn seriously…is dangerous bliss.
Angie

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Anonymous January 27, 2012 at 1:35 am

I find this very interesting. I'm a 3rd year pharmacy student and narcoleptic. I was skeptical of a direct link between the influenza vaccine and narcolepsy. I feel like many environmental/bacterial/viral triggers lead to turning on of narcolepsy genes. I feel narcoleptics want a solid 'why' so they take vaccines and run with it. Thanks for the reputable study info.

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Rebecca February 17, 2014 at 8:17 pm

My symptoms actually started the year I first received the H1N1 vaccination. I got the vaccine at a clinic at my school, and that same year I started experiencing microsleeps during class.

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