Improving the nosology of Long COVID: it is not so simple.

Long COVID is a diagnostic label currently given to those suffering from a poorly understood state of incomplete recovery or who have development of a myriad of medically unexplained symptoms occurring in the wake of infection with SARS CoV-2 that is both poorly understood and controversial. Many of the features of one of the most common clinical endotypes of Long COVID are shared by a condition well familiar to all rheumatologists and one with a large body of epidemiologic, clinical and basic research accrued over many decades namely the syndrome of fibromyalgia. Some have recently suggested that Long COVID may merely be a new name for fibromyalgia and that this diagnosis is indeed the condition that many or most may be suffering from as a post infectious sequela. In this Viewpoint we argue that while the parallels between the clinical syndrome experienced by many of those currently labeled as Long COVID and fibromyalgia are strong we should be not too quick to rename the disorder. We further argue that relabeling Long COVID as fibromyalgia is clinically reductionistic and any such relabeling may be attended by harm in both the design and execution of a future research agenda as well to patients who may be inadvertently and unfortunately pejoritised by such labeling. We further explore the parallels and differences between Long COVID and fibromyalgia and outline areas of needed future research and care.