Recognized since the early 1800s, Guillain-BarrÃ© syndrome is a rare, paralyzing and potentially catastrophic disorder of the peripheral nerves. It involves a sudden attack on the nerves that control movement - both voluntary, like walking, and involuntary, like breathing. People may spend months in hospital, not knowing if or when they will recover. Some face long-term disability. The disease is of variable severity; in mild cases the victim can still walk, while in the most severe sufferers are reduced to a state of near-paralysis. Four out of five victims eventually recover fully but it takes several years for the injured nerves to completely repair themselves. Younger people recover more quickly. There is around a five percent mortality rate, usually from respiratory complications or heart problems.
The cause of the disease is unknown, but about two-thirds of cases are preceded by a respiratory or gastrointestinal infection. A significant minority of cases follow infection by two herpes viruses, cytomegalovirus or Epstein-Barr virus, the cause of infectious mononucleosis. Some cases have been triggered by immunizations against infections such as influenza.