In addition, another major subgroup has become apparent; that of Long-COVID patients displaying Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) related symptoms [2] [3]. It is estimated that around half of individuals with Long-COVID meet the criteria for ME/CFS 2 . This would equate to around 5-10 million additional (LongCOVID related) ME/CFS patients in the USA, alone. However, no mention of any of these major subgroups (or possible subsets within) is provided by the WHO in their clinical case definition [1]. Consequently, contrasting definitions for Long-COVID have appeared in the literature. Some reviewers perceive it as pertaining only to the subgroup related to long-term ME/CFS-like symptoms3 , whereas others perceive Long-COVID as pertaining to all subgroups and long-term pathophysiological outcomes, some including those with ME/CFS-like symptoms and some without4 .