Abstract Long COVID can sometimes be attributed to organ damage and well-characterized pathophysiology, but more often there is no evidence of organ damage or abnormal biomarkers. This is most evident in patients with mild to moderate initial SARS-CoV-2 infection who were not hospitalized. Their persistent symptoms are strikingly similar to those of fibromyalgia (FM) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), including fatigue, post exertional malaise, myalgias/arthralgias, sleep and cognitive disturbances in 50-100% of cases. Analogous pathophysiologic pathways in FM, ME/CFS and long COVID include host-microbial interactions in the absence of direct tissue invasion, an absence of systemic autoimmunity, but evidence for immune dysregulation, as well as autonomic, peripheral, and central nervous system dysfunction. Current treatment of long COVID has been based on multidisciplinary management recommended for FM and ME/CFS but has been formalized and widely available by funding for nation-wide long COVID clinics. Long COVID and its treatment should be distinguished by the presence or absence of organ damage. The acknowledged role of patient engagement in research and open dialogue regarding work and disability noted in long COVID may have meaningful impact on patients with FM and ME/CFS. Hopefully, advances in long COVID basic research will aid in understanding FM and ME/CFS and rheumatologists should be involved in such research and patient care. https://onlinelibrary.wiley.com/doi/abs/10.1002/acr.25210
