Monday, August 22, 2011

Stanford Study Finds Influenza – Narcolepsy Connection





Photo Credit CDCSleep and Sleep Disorders

# 5772


Over the past year we’ve seen numerous reports linking GSK’s Pandemrix vaccine to an increased incidence of narcolepsy in children and adolescents. This recently led the EMA to recommend that the vaccine not be given to anyone under the age of 20.


Somewhat mysteriously, epidemiological investigations have confirmed elevated levels of childhood narcolepsy among Pandemrix vaccine recipients in some countries, but not in others.


And last year Iceland reported a similar surge in narcolepsy among children who had not received the vaccine.


Leaving many to question exactly what is going on here.


Today, in a study that appears in the Annals of Neurology, we’ve a new study that now suggests a link between contracting an upper respiratory infection and developing narcolepsy.


I’ve listed the full citation below, but as of this posting the link is not live.


"Narcolepsy Onset is Seasonal and Increased Following the H1N1 Pandemic in China." Fang Han, Ling Lin, Simon C Warby, Juliette Faraco, Jing Li , Song X. Dong, Pei. An, Long Zhao, Ling H. Wang, Qian Y. Li, Han Yan, Zhan C. Gao, Yuan Yuan, Kingman P. Strohl and Emmanuel Mignot, Annals of Neurology; Published Online: August 22, 2011 (DOI:10.1002/ana.22587).


We do have a pair of press releases, however, that provide a fair amount of background on this intriguing finding.


And what these researchers found was: that in China, among a largely unvaccinated population, the incidence of Narcolepsy increased dramatically in the Spring, after the winter flu season. And that this increase was most pronounced following the emergence of the H1N1 swine flu virus in 2009.


Study finds narcolepsy cases in China peak in early spring

Significant spike following H1N1 pandemic not linked to vaccines

New research shows that the occurrence of narcolepsy in China is highly correlated to a seasonal pattern, with onset most frequent in April. A significant increase in narcolepsy cases was also observed following the 2009-2010 H1N1 pandemic, but the findings now available in Annals of Neurology, a journal of the American Neurological Association and the Child Neurology Society, report flu vaccination was unlikely the cause of the increase.

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Stanford study draws connection between narcolepsy and influenza

STANFORD, Calif. — The onset of narcolepsy appears to follow seasonal patterns of H1N1 and other upper airway infections, according to a new study of patients in China that was led by Stanford University School of Medicine narcolepsy expert Emmanuel Mignot, MD.


The findings, which will be published online Aug. 22 in Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society, show that a peak in narcolepsy cases occurred five to seven months after a peak in flu/cold or H1N1 infections in the country.


"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 study follows recent reports that a particular H1N1 vaccine, not one used in the United States or China, seemed to lead to narcolepsy. This new paper, however, found no correlation between vaccination and narcolepsy among the patients studied in China. "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," the authors wrote.


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The results of today’s study is reminiscent to one we saw last year (see Lancet: The Influenza - Guillain Barré Syndrome Connection) that suggested the risks of developing GBS – another type of autoimmune disease - were far greater following a bout of the flu, than from receiving the flu vaccine.


And two years ago, Helen Branswell reported on a study that suggested that some influenza infections may set up some people to develop Parkinson's disease later in life (see More On The Influenza-Parkinson’s Link.)


One of the authors of today’s study, Dr. Emmanuel Mignot with the Stanford Center for Sleep Sciences and Medicine in Palo Alto, California, is quoted as saying:


"These findings are reminiscent of the encephalitis lethargica epidemic that followed the great Spanish influenza pandemic of 1917-1918. Not only narcolepsy, but also psychosis and Parkinson's disease may follow winter infections, and further research is needed in the area of autoimmune diseases of the brain.”


The epidemic of Encephalitis lethargica that swept the world between 1915 and 1926 remains one of the great medical mysteries of the last century, although a link to the Pandemic virus of 1918 has often been suggested.


As the press release states: The paper doesn't show cause and effect, but it does show a strong correlation between narcolepsy onset and this seasonal pattern.

More research is obviously needed, but this is more evidence that the real danger lies with contracting the flu, not with taking the vaccine to prevent it.