Before there was long covid there was Encephalitis lethargica or the sleeping sickness, vanishing around 1927 as mysteriously as it appeared alongside Spanish flu epidemic. Many individuals afterwards suffered from severe parkinsonism, prisoners in their own body and barely able to move for years until the drug L-dopa was found to “unlock” them many years later in the 1960s. Made famous of course in Oliver Sack’s book “Awakenings.” Also featured prominently in the Sandman comics. The exact cause of the illness still uncertain to this day, though evidence exists for multiple theories.