To understand why long Covid represents a looming catastrophe, we need look no further than the historical antecedents: similar postinfection syndromes. Experience with conditions such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), fibromyalgia, post-treatment Lyme disease syndrome, chronic Epstein–Barr virus, and even the 19th-century diagnosis of neurasthenia could foreshadow the suffering of patients with long Covid in the months and years after infection.