Figure 1.

Long COVID subtypes, including Non-Syndromic Long COVID, Syndromic Long COVID, and ‘Red herrings’.

Patients with Non-Syndromic Long COVID may have had a severe acute infection that resulted in hospitalization and caused significant organ damage and dysfunction. This subtype may respond well to traditional interventional approaches, such as pulmonary rehabilitation. By contrast, patients with Syndromic Long COVID might have had a mild acute infection that did not require hospitalization, but develop extreme fatigue, shortness of breath, chest pain, and exertional intolerance. This subtype tends to not respond well to conventional treatments. Within this subtype, certain pre-existing chronic illnesses, such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), may be worsened by the acute COVID. Furthermore, ‘Red herrings’ is the long tail recovery from acute COVID, where symptoms gradually resolve within a few months without any intervention. Abbreviation: PESE: Post-Exertional Symptom Exacerbation.