British researchers blame swine flu vaccine for a sudden increase in cases of narcolepsy among schoolchildren in Finland, reports The Independent.

Narcolepsy is characterised by periods of extreme drowsiness, sudden naps, and paralysis attacks. Increase in rates of this sleeping disorder rates was reported among Finnish children early in 2010.

On comparing the narcolepsy rates between 2002 and 2009, and 2010, researchers found that the rate of narcolepsy in children under the age of 17 was 0.31 per 100,000 between 2002 and 2009, before the swine flu pandemic struck.

Vaccination and childhood narcolepsy data for children born between January 1991 and December 2005 was collected by Markku Partinen of the Helsinki Sleep Clinic and Hanna Nohynek of the National Institute for Health and Welfare in Finland.

The data collected by Markku Partinen and Hanna Nohynek showed that those who were vaccinated the rate of narcolepsy was nine per 100,000 compared to 0.7 per 100,000 unvaccinated children, or 13 times lower.

Researchers, whose study was published in the journal Public Library of Science ONE, concluded by saying, "We consider it likely that Pandemrix vaccination contributed, perhaps together with other environmental factors, to this increase in genetically susceptible children."

Study authors suspect that the Pandemrix vaccine may have contributed to an auto-immune effect linked to narcolepsy.