Pandremrix is a influenza vaccine that was developed by Glaxo SmithKline, initially as a H5N1 (Bird Flu) mockup pandemic vaccine. In 2009 it was rapidly redeveloped to combat the H1N1 (Swine Flu) outbreak, going though a limited testing cycle. It differs from other H1N1 vaccines (e.g. Celvapan, Focetria) in that instead of using an inactivated whole cell virus, it used a part of the H1N1 virus and a strong immunologic adjuvant (AS03) to boost the immune system response.
At the end of the H1N1 pandemic in 2010, as reports of Narcolepsy-like symptoms started to emerge from Scandinavia and other European countries, Pandemrix was withdrawn from use in most countries.
Studies have since observed a significantly raised likelihood of developing Narcolepsy following use of the Pandemrix vaccine. It has also been discovered that Narcolepsy is caused by an auto-immune response to a part of the H1N1 virus (also used in Pandemrix), whereby the immune system mistakes the sleep/awakeness regulating neuropeptide Hypocretin (aka Orexin) for the virus, attacking and destroying the cells in the brain that create it.