Keywords: PASC, ME/CFS, Classification system


This study aimed to contribute to the development of a research case definition for post-acute sequelae of SARS CoV-2 infection (PASC) using a PASC data set and experiences from case definitions developed for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).  Our database included patients with PASC who provided self-report symptomology during the onset of infection and the time of survey completion (post-infection).  We found that we could distinguish between those with mild, moderate, and severe PASC.  Regarding the proportion meeting an ME/CFS case definition, we found 0% in the mildly impaired group, 30.6% to 62.6% in the moderately impaired group, and 74.3% to 89.0% in the severely impaired group. Based on these preliminary data, we propose a 5-part classification system for PASC.  Axis 1 involves the variant of the COVID infection and the type of documentation of the infection. Axis 2 involves the time elapsed since infection. Axis 3 involves the type of medical collateral damage to different organs. Axis 4 involves functional impairment classified into three categories: mild, moderate, or severe.  Finally, Axis 5 is the identified symptoms. Finally, if the patient has been sick for 6 or more months, it is important to determine whether the person has met the ME/CFS criteria.  This proposed 5-part classification system for PASC might bring considerable clarity to diagnosing PASC.   


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