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    Home > Adult Immunisation > Flu Vaccination > FAQ

Narcolepsy Information

April 2012



What is narcolepsy?

Narcolepsy is a disease which causes a disturbance in the ability to regulate sleep. There is about one new case per 100,000 of the population every year. It can lead to broken sleep at night and feeling very sleepy during the day. Other symptoms people can get include;

  • Being unable to move when they start to fall asleep or when they first wake up.
  • Vivid sometimes frightening dreams when they are waking up.
  • Sudden weakness in their muscles when they are awake. This can vary from mild weakness in the face to the knees giving way.

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What causes narcolepsy?

Experts believe that in most people, narcolepsy is due to a reduction in a protein (hypocretin) made in the brain but they do not know what causes this reduction. The exact cause of narcolepsy is currently unknown. It is generally considered to be triggered by genetic and environmental factors including infections  

Anyone with concerns about narcolepsy should speak to their GP.

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What is Pandemrix?

Pandemrix is a vaccine against the H1N1 (2009) influenza (swine flu) virus. It was used during the H1N1 influenza pandemic to protect people from infection and complications due to the H1N1 influenza virus. Over 900,000 doses were used in Ireland.

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Is Pandemrix still being used? 

Pandemrix has not been recommended in Ireland since January 2011. Doctors were requested to return all stocks of Pandemrix for disposal.

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Is there an association between Pandemrix and narcolepsy?

All medication, including vaccines, can potentially lead to adverse effects in a small number of individuals. It is not always easy to be certain of potential rare adverse effects even after a medicine has been used in very large numbers of people. 

In August 2010 the European Medicines Agency began to investigate a suggested link in Finland and Sweden between the use of Pandemrix and the development of narcolepsy in young people.  

Finland and Sweden have carried out studies and the results indicate a 6 to 13-fold increased risk of narcolepsy in vaccinated as compared with unvaccinated children and adolescents.The increased risk was not seen in adults (older than 20 years). 

In Ireland experts are carrying out an investigation into cases of narcolepsy that developed following the use of Pandemrix in the winter of 2009/2010. So far 25 cases have been confirmed.

Worldwide as of 3rd August 2011

  • over 31 million doses of Pandemrix have been administered worldwide in 47 countries
  • 335 cases of narcolepsy have been reported in people vaccinated with Pandemrix
  • 2/3rd of these cases originated from Finland and Sweden

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Is there a difference between seasonal flu vaccine and Pandemrix?

Yes. The seasonal flu vaccine and Pandemrix are two different vaccines. They are manufactured in completely different ways.  

Seasonal flu vaccines have been given for more than 60 years to millions of people across the world. Reactions are generally mild and serious side effects are very rare.

Narcolepsy has not been reported following seasonal influenza vaccination.

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Should young people with at risk medical conditions get seasonal flu vaccine?

Young people with at risk medical conditions should get the seasonal flu vaccine. Seasonal flu is a highly infectious viral illness of the respiratory tract that can be life threatening. The flu virus changes each year and this is why people at risk need to be vaccinated every year.

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Health Protection Surveillance Centre The Department of Health and Children Irish College Of General Practitioner