CDC statement on narcolepsy following Pandemrix influenza vaccination in Europe

An increased risk of narcolepsy was found following vaccination with Pandemrix, a monovalent 2009 H1N1 influenza vaccine that was used in several European countries during the H1N1 influenza pandemic. Narcolepsy is a chronic neurological disorder caused by the brain’s inability to regulate sleep-wake cycles normally. This risk was initially found in Finland, and then some other European countries also detected an association. Most recently, scientists at the United Kingdom’s (UK) Health Protection Agency (HPA) have found evidence of an association between Pandemrix and narcolepsy in children in England. The findings are consistent with studies from Finland and other countries.

Pandemrix is manufactured by GlaxoSmithKline in Europe and was specifically produced for pandemic 2009 H1N1 influenza. It was not used before 2009, and has not been used since the influenza pandemic season (2009-2010). It contains an oil-in-water emulsion adjuvant called ASO3. Adjuvants are substances added to a vaccine to increase the body’s immune response to that vaccine.

Pandemrix was not licensed for use in the United States. In fact, no adjuvanted influenza vaccines are licensed in the United States, and no adjuvanted influenza vaccines were used in the United States during the influenza pandemic or in any other influenza season.

In response to the events in Europe, CDC reviewed data from the U.S. Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink (VSD) and to date have found no indication of any association between U.S.-licensed H1N1 or seasonal influenza vaccine and narcolepsy.

CDC is currently sponsoring an international study on the associations between adjuvanted monovalent 2009 H1N1 influenza vaccines and narcolepsy. That study is expected to be completed in 2014.

CDC recommends influenza vaccination as the best way to protect from influenza disease and its complications. CDC recommendations for influenza vaccine during the 2012-2013 season can be found at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6132a3.htm.

For more information, please visit the following websites:

• National Institutes of Health (NIH) Narcolepsy Fact Sheet: http://www.ninds.nih.gov/disorders/narcolepsy/detail_narcolepsy.htm
• National Vaccine Advisory Committee (NVAC) H1N1 Reports: http://www.hhs.gov/nvpo/nvac/reports/index.html
• 2012-2013 U.S.-licensed influenza vaccines: Food and Drug Administration (FDA)
  http://www.fda.gov/BiologicsBloodVaccines/Vaccines/ApprovedProducts/UCM093833

Scientific articles on this subject can be found at:

• Miller et al. Risk of narcolepsy in children receiving an AS03 adjuvanted AH1N1 (2009) influenza vaccine in England. (2013). British Medical Journal. http://www.bmj.com/cgi/doi/10.1136/bmj.f794
• Partinen et al. Increased incidence and clinical picture of childhood narcolepsy following the 2009 H1N1 pandemic vaccination campaign in Finland. PLoS One. 2012;7(3):e33723.
  Available online: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0033723
• Nohynek et al. AS03 adjuvanted AH1N1 vaccine associated with an abrupt increase in the incidence of childhood narcolepsy in Finland. PLoS One. 2012;7(3):e33536.
  Available online: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033536
• Eurosurveillance editorial team. Swedish Medical Products Agency publishes report from a case inventory study on Pandemrix vaccination and development of narcolepsy with cataplexy. Euro Surveill. 2011;16(26):pii=19904.
  Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19904
• ECDC Technical Report: Narcolepsy in association with pandemic influenza vaccination, a multi-country European epidemiological investigation  [PDF - 8 MB]

http://www.cdc.gov/vaccinesafety/Concerns/h1n1_narcolepsy_pandemrix.html