Swine Flu Shot Linked to Narcolepsy

After an aggressive H1N1 vaccination campaign in Finland in 2009, the country's National Institute for Health and Welfare, THL, recommended discontinuing use of the swine flu shot due to a suspected link between the vaccine and narcolepsy in young people. THL observes what it calls a "manifold increased risk of falling ill with narcolepsy" among children and youth who received H1N1 vaccines. The agency is set to investigate other factors that may have jointly contributed to the increase. Their final report is expected by August 31, 2011.

A preliminary study shows an increase in new childhood cases of narcolepsy, from 7 cases in Finland in 2007 to 60 in 2009-2010. Of those reported in 2009-2010, 90 percent had received GlaxoSmithKline's Pandemrix H1N1 influenza vaccine. Symptoms began in most of these cases within two to 10 weeks of vaccination. Children under age four and adults over age 19 were not affected by the increase in narcolepsy.

Narcolepsy-Swine Flu Shot Link Uncertain

While THL claims the link between the vaccine and narcolepsy is "so evident that it is unlikely that other so-called confounding factors could fully explain the phenomenon," the UK's Medicines and Healthcare products Regulatory Agency (MHRA) notes there was an increase in narcolepsy in both Sweden and Iceland affecting people who had not been vaccinated. No increase in narcolepsy incidence has been observed outside of Scandinavia, despite the fact that millions of doses of the vaccine were administered worldwide. An MHRA spokesperson calls the vaccine-narcolepsy link "far from clear cut."

Correlation or Cause?

Correlation - two things happening together - does not mean one caused the other. Because many countries offered free swine flu shots to children and aggressively promoted H1N1 vaccination, it is not surprising that most of the young people affected were vaccinated.

A similar leap of logic resulted in multiple outbreaks of measles, after a link between autism and the measles, mumps and rubella (MMR) vaccine was observed. There is correlation between MMR vaccination and onset of observed autism symptoms in many children, but this has more to do with the fact that the vaccine is usually given around 18 months, a time when parents and doctors begin to note signs of a developmental delay. A large number of scientific studies have been conducted, and none has ever proved MMR vaccines cause autism. Many parents choose not to vaccinate their children, even after the paper that originally suggested the autism-vaccine link was withdrawn, and the main author's license to practise medicine removed.

Narcolepsy is a rare sleep disorder marked by frequent periods of excessive drowsiness, and by falling asleep during the daytime. This can result in disruption of work and social activities. Physical injuries can occur, if the person falls asleep during an activity.

Sources:

Eurosurveillance editorial team, "European Medicines Agency updates on the review of Pandemrix and reports of narcolepsy." Eurosurveillance

"Narcolepsy." US National Library of Medicine / National Institutes of Health

"Swine flu-narcolepsy link dismissed." UK Press Agency

"Swine flu vaccine likely causes child narcolepsy: study." Agence France-Presse