Long COVID

Nature   surveys the state of knowledge 

More than 200 symptoms have been identified with impacts on multiple organ systems. At least 65 million individuals worldwide are estimated to have long COVID, with cases increasing daily. Biomedical research has made substantial progress in identifying various pathophysiological changes and risk factors and in characterizing the illness; further, similarities with other viral-onset illnesses such as myalgic encephalomyelitis/chronic fatigue syndrome and postural orthostatic tachycardia syndrome have laid the groundwork for research in the field. In this Review, we explore the current literature and highlight key findings, the overlap with other conditions, the variable onset of symptoms, long COVID in children and the impact of vaccinations. 

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There are likely multiple, potentially overlapping, causes of long COVID. Several hypotheses for its pathogenesis have been suggested, including persisting reservoirs of SARS-CoV-2 in tissues16,17; immune dysregulation17–20 with or without reactivation of underlying patho- gens, including herpesviruses such as Epstein–Barr virus (EBV) and human herpesvirus 6 (HHV-6) among others17,18,21,22; impacts of SARS- CoV-2 on the microbiota, including the virome17,23–25; autoimmun- ity17,26–28andprimingoftheimmunesystemfrommolecularmimicry17; microvascular blood clotting with endothelial dysfunction17,29–31; and dysfunctional signalling in the brainstem and/or vagus nerve17,32 (Fig. 3). Mechanistic studies are generally at an early stage, and although work that builds on existing research from postviral illnesses such as ME/CFS has advanced some theories, many questions remain and are a priority to address. 

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Early research shows an increasing risk of long COVID sequelae after the second and third infection, even in double-vaccinated and triple-vaccinated people182. Existing literature suggests multiple infec- tions may cause additional harm or susceptibility to the ME/CFS-type presentation33,183.
There is also early evidence that certain immune responses in people with long COVID, including low levels of protective antibod- ies and elevated levels of autoantibodies, may suggest an increased susceptibility to reinfection27.
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Conclusions
Long COVID is a multisystemic illness encompassing ME/CFS, dysauto- nomia, impacts on multiple organ systems, and vascular and clotting abnormalities. It has already debilitated millions of individuals world- wide, and that number is continuing to grow. On the basis of more than 2 years of research on long COVID and decades of research on condi- tions such as ME/CFS, a significant proportion of individuals with long COVID may have lifelong disabilities if no action is taken. Diagnostic and treatment options are currently insufficient, and many clinical trials are urgently needed to rigorously test treatments that address hypoth- esized underlying biological mechanisms, including viral persistence, neuroinflammation, excessive blood clotting and autoimmunity.

Monbiot   has a nice article (includes links to primary sources)

We are all playing Covid roulette. Without clean air, the next infection could permanently disable you