Scientists start to unpick narcolepsy link to GSK flu vaccine

By Kate Kelland LONDON (Reuters) – Scientists have found that the sleep disorder narcolepsy can sometimes be triggered by a scientific phenomenon known as “molecular mimicry”, offering a possible explanation for its link to a GlaxoSmithKline H1N1 pandemic flu vaccine. Results from U.S. researchers showed the debilitating disorder, characterized by sudden sleepiness and muscle weakness, can be set off by an immune response to a portion of a protein from the H1N1 virus that is very similar to a region of a protein called hypocretin, which is key to narcolepsy. Previous studies in countries where GSK’s Pandemrix vaccine was used in the 2009/2010 flu pandemic have found its use was linked to a significant rise in cases of narcolepsy in children. Studies in Britain, Finland, Sweden and Ireland found such a link, and GSK says at least 900 narcolepsy cases associated with the vaccine have so far been reported in Europe.