Narcolepsy Associated With the Swine Flu Vaccination?


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Pandemrix vaccine was given during the 2009 swine flu pandemic. Photo by: Alcibiades

Pandemrix vaccine was given during the 2009 swine flu pandemic. Photo by: Alcibiades

H1N1 Vaccine Side Effects: Current Research

In England, a team of researchers evaluated the risk of narcolepsy associated with the Pandemrix vaccine.

To do this, researchers reviewed case notes from 245 children ages four to 18 years of age from sleep centers and neurology centers across England from August 2011 to February 2012. Of these 245 cases, 75 of them had narcolepsy with onset after January 1, 2008. Eleven of them had been vaccinated before the onset of symptoms and seven of them within six months of getting symptoms.

The results of the England study found that vaccination at any time was associated with a 14-fold increase risk of narcolepsy, and vaccination within six months before onset was associated with a 16-fold increased risk. This means that one in 52,000 to 57,500 doses of flu vaccine are associated with the development of narcolepsy.

Swine Flu Vaccine Caused Narcolepsy in Kids

The researchers concluded that there is a causal relationship between narcolepsy and the swine flu vaccination. What does this mean? A causal relationship exists when you have two variables and a change in one variable, results in a change in the other variable. In this case, the swine flu vaccine changed the number of children diagnosed with narcolepsy. The results of this study were also consistent with those results from the Finland study. However, according to the study, the results may be overestimated due to the rapid referral of vaccinated children.

Interview with Elizabeth Miller, MBBS

To understand more about this study and the implications of these results, Decoded Science had the opportunity to interview Elizabeth Miller, MBBS, who was the consulting epidemiologist for this study. Decoded Science asked Dr. Miller if there was something in the ingredients of the vaccine that was causing narcolepsy, and Dr. Miller explained that, “Further research would need to be carried out in order to understand which component of the vaccine was responsible for the increased risk of developing narcolepsy following vaccination.”

I also asked her if she though that the vaccine, Pandemrix was tested thoroughly enough, considering the rapid turn-around between vaccine development and vaccination of large populations of people. Dr. Miller replied, “Decisions on implementing new vaccination programs are based on advice from the Government’s independent group of experts – the Joint Committee on Vaccination and Immunisation (JCVI) which takes all safety evidence into account before making its recommendations.”

I also asked Dr. Miller if she thought that there could be other vaccines that could also cause narcolepsy and she explained, “The Medicines and Healthcare products Regulatory Agency (MHRA) continuously monitors the safety of all vaccines. No other vaccines have been associated with narcolepsy and this issue has no implications for the safety of the seasonal influenza vaccination program. Influenza can cause severe illness and it is important that people at risk are vaccinated with current seasonal flu vaccines as recommended.”

Vaccine Safety: Hindsight is 20/20

Although some parents may have concerns over the ingredients in the flu vaccines and the possible side effects that ingredients like mercury can cause, Elizabeth Miller says, “vaccination remains the most effective way of reducing the risk of serious infection associated with novel viruses.” Unfortunately, in cases such as this, the attendant risks and unusual side effects associated with a novel flu vaccine may take years to fully identify, so weighing the benefits and dangers is a difficult proposition for parents.


Miller, E., Andrews, N., Stelliitano, L., et al. Risk of Narcolepsy in children and young people receiving the AS03 adjuvanted pandemic A/H1N1 2009 influenza vaccine: retrospective analysis. (2013). British Medical Journal 2013, 346. Accessed March 1, 2013.

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